Prepare codebase for dynamic DMaaP configuration

From now on, there is only one single place
where we can create whole app core concerning sending events
and it has a single entry point, based on DMaaP configuration.
It can be used to rebuild part of app that is responsible
for sending events dynamically.
Changes are in scope for the dynamic DMaaP config feature.
+ bumped up code coverage a bit

Change-Id: Iecc8c4e534ae9b781f47e3616409271ba83169c8
Signed-off-by: PawelSzalapski <pawel.szalapski@nokia.com>
Issue-ID: DCAEGEN2-517

14 files changed, 815 insertions, 685 deletions

diff --git a/src/main/java/org/onap/dcae/commonFunction/AnyNode.java b/src/main/java/org/onap/dcae/commonFunction/AnyNode.java
index 267c87a9..97d73ddd 100644
--- a/src/main/java/org/onap/dcae/commonFunction/AnyNode.java
+++ b/src/main/java/org/onap/dcae/commonFunction/AnyNode.java
@@ -19,164 +19,95 @@
  */
 package org.onap.dcae.commonFunction;
 
+import static io.vavr.API.Set;
+
+import io.vavr.collection.List;
+import io.vavr.collection.Set;
+import io.vavr.control.Option;
+import java.util.stream.StreamSupport;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
-import org.json.JSONTokener;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.io.FileNotFoundException;
-import java.io.FileReader;
-import java.io.IOException;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
-import java.util.Set;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
-import java.util.stream.StreamSupport;
 
 /**
- * This class is a wrapper for 2 most used entities of org.json lib: JSONArray and JSONObject and
- * comprises utility methods for fast access of json structures without need to explicitly coerce between them.
- * While using this, bear in mind it does not contain exception handling - it is assumed that when using, the parsed json structure is known.
+ * This class is a wrapper for 2 most used entities of org.json lib: JSONArray and JSONObject and comprises utility
+ * methods for fast access of json structures without need to explicitly coerce between them. While using this, bear in
+ * mind it does not contain exception handling - it is assumed that when using, the parsed json structure is known.
  *
  * @author koblosz
  */
 public class AnyNode {
-    private final Object obj;
-    private static final Logger log = LoggerFactory.getLogger(AnyNode.class);
 
-    public static AnyNode parse(String filePath) throws IOException {
-        try (FileReader fr = new FileReader(filePath)) {
-            return new AnyNode(new JSONObject(new JSONTokener(fr)));
-        } catch (FileNotFoundException | JSONException e1) {
-            log.error("Could not find or parse file under path %s due to: %s", filePath, e1.toString());
-            e1.printStackTrace();
-            throw e1;
-        }
-    }
+    private Object obj;
 
-    /**
-     * Returns key set of underlying object. It is assumed that underlying object is of type org.json.JSONObject.
-     *
-     * @return Set of string keys present in underlying JSONObject
-     */
-    public Set<String> getKeys() {
-        return asJsonObject().keySet();
+    private AnyNode(Object object) {
+        this.obj = object;
     }
 
-    /**
-     * Returns value associated with specified key wrapped with AnyValue object. It is assumed that this is of type org.json.JSONObject.
-     *
-     * @param key A key string
-     * @return The AnyNode object associated with given key.
-     */
-    public AnyNode get(String key) {
-        return new AnyNode(asJsonObject().get(key));
+    public static AnyNode fromString(String content) {
+        return new AnyNode(new JSONObject(content));
     }
 
     /**
-     * Returns value under specified index wrapped with AnyValue object. It is assumed that this is of type org.json.JSONArray.
-     *
-     * @param idx An index of JSONArray
-     * @return The AnyNode object associated with given index.
+     * Returns key set of underlying object. It is assumed that underlying object is of type org.json.JSONObject.
      */
-    public AnyNode get(int idx) {
-        return new AnyNode(asJsonArray().get(idx));
+    public Set<String> keys() {
+        return Set(asJsonObject().keySet().toArray(new String[]{}));
     }
 
     /**
-     * Returns int assuming this can be coerced to int.
+     * Returns value associated with specified key wrapped with AnyValue object. It is assumed that this is of type
+     * org.json.JSONObject.
      */
-    public int asInt() {
-        return (int) this.obj;
+    public AnyNode get(String key) {
+        return new AnyNode(asJsonObject().get(key));
     }
 
     /**
-     * Returns string representation of this. If it happens to have null, the value is treated as org.json.JSONObject.NULL and "null" string is returned then.
-     *
-     * @return A String
+     * Returns string representation of this. If it happens to have null, the value is treated as
+     * org.json.JSONObject.NULL and "null" string is returned then.
      */
-    public String asString() {
-        return this.obj != JSONObject.NULL ? (String) this.obj : JSONObject.NULL.toString();
-    }
-
     public String toString() {
         return this.obj.toString();
     }
 
     /**
-     * Converts underlying object to String-to-Object map. It is assumed that underlying object is of type org.json.JSONObject.
-     *
-     * @return A map.
+     * Returns optional of object under specified key, wrapped with AnyNode object.
+     * If underlying object is not of type org.json.JSONObject
+     * or underlying object has no given key
+     * or given key is null
+     * then Optional.empty will be returned.
      */
-    public Map<String, Object> asRawMap() {
-        return asJsonObject().toMap();
-    }
-
-    /**
-     * Returns optional of object under specified key, wrapped with AnyNode object. If underlying object is not of type org.json.JSONObject, then Optional.empty will be returned.
-     *
-     * @param key A key string
-     */
-    public Optional<AnyNode> getAsOptional(String key) {
-        AnyNode result = null;
+    public Option<AnyNode> getAsOption(String key) {
         try {
-            result = get(key);
-        } catch (JSONException ignored) {
+            AnyNode value = get(key);
+            if (value.toString().equals("null")) {
+                return Option.none();
+            }
+            return Option.some(value);
+        } catch (JSONException ex) {
+            return Option.none();
         }
-        return Optional.ofNullable(result);
-    }
-
-    private JSONObject asJsonObject() {
-        return (JSONObject) this.obj;
-    }
-
-    /**
-     * Converts underlying object to map representation with map values wrapped with AnyNode object. It is assumed that underlying object is of type org.json.JSONObject.
-     */
-    public Map<String, AnyNode> asMap() {
-        Map<String, AnyNode> map = new HashMap<>();
-        getKeys().forEach(key -> map.put(key, get(key)));
-        return map;
-    }
-
-    /**
-     * Converts underlying object to map representation with map values wrapped with AnyNode object. It is assumed that underlying object is of type org.json.JSONObject.
-     */
-    public java.util.List<AnyNode> asList() {
-        return asStream().collect(Collectors.toList());
     }
 
     /**
-     * Converts this object to stream of underlying objects wrapped with AnyNode class. It is assumed that this is of type JSONArray.
+     * Converts underlying object to map representation with map values wrapped with AnyNode object. It is assumed that
+     * underlying object is of type org.json.JSONObject.
      */
-    private Stream<AnyNode> asStream() {
-        return StreamSupport.stream(((JSONArray) this.obj).spliterator(), false).map(AnyNode::new);
+    public List<AnyNode> toList() {
+        return List.ofAll(StreamSupport.stream(((JSONArray) this.obj).spliterator(), false).map(AnyNode::new));
     }
 
     /**
      * Checks if specified key is present in this. It is assumed that this is of type JSONObject.
      */
-    boolean hasKey(String key) {
-        return getAsOptional(key).isPresent();
-    }
-
-    /**
-     * Returns empty AnyNode (with null inside)
-     */
-    public static AnyNode nullValue() {
-        return new AnyNode(JSONObject.NULL.toString());
+    public boolean has(String key) {
+        return !getAsOption(key).isEmpty();
     }
 
-    private JSONArray asJsonArray() {
-        return (JSONArray) this.obj;
+    private JSONObject asJsonObject() {
+        return (JSONObject) this.obj;
     }
 
-    private AnyNode(Object object) {
-        this.obj = object;
-    }
 
 }
diff --git a/src/main/java/org/onap/dcae/commonFunction/CambriaPublisherFactory.java b/src/main/java/org/onap/dcae/commonFunction/CambriaPublisherFactory.java
deleted file mode 100644
index 79109c04..00000000
--- a/src/main/java/org/onap/dcae/commonFunction/CambriaPublisherFactory.java
+++ /dev/null
@@ -1,64 +0,0 @@
-package org.onap.dcae.commonFunction;
-/*-
- * ============LICENSE_START=======================================================
- * org.onap.dcaegen2.collectors.ves
- * ================================================================================
- * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
- * Copyright (C) 2018 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-import com.att.nsa.cambria.client.CambriaBatchingPublisher;
-import com.att.nsa.cambria.client.CambriaClientBuilders;
-import java.net.MalformedURLException;
-import java.security.GeneralSecurityException;
-import java.util.Map;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-class CambriaPublisherFactory {
-
-    private final static Logger log = LoggerFactory.getLogger(CambriaPublisherFactory.class);
-
-    CambriaBatchingPublisher createCambriaPublisher(String streamId)
-            throws MalformedURLException, GeneralSecurityException {
-        String authpwd = null;
-        DmaapPropertyReader reader = DmaapPropertyReader.getInstance(CommonStartup.cambriaConfigFile);
-        Map<String, String> dMaaPProperties  = reader.getDmaapProperties();
-        String ueburl = dMaaPProperties.get(streamId + ".cambria.url");
-
-        if (ueburl == null) {
-            ueburl = dMaaPProperties.get(streamId + ".cambria.hosts");
-        }
-        String topic = reader.getKeyValue(streamId + ".cambria.topic");
-        String authuser = reader.getKeyValue(streamId + ".basicAuthUsername");
-
-        if (authuser != null) {
-            authpwd = dMaaPProperties.get(streamId + ".basicAuthPassword");
-        }
-
-        if ((authuser != null) && (authpwd != null)) {
-            log.debug(String.format("URL:%sTOPIC:%sAuthUser:%sAuthpwd:%s", ueburl, topic, authuser, authpwd));
-            return new CambriaClientBuilders.PublisherBuilder().usingHosts(ueburl).onTopic(topic).usingHttps()
-                    .authenticatedByHttp(authuser, authpwd).logSendFailuresAfter(5)
-                    .build();
-        } else {
-            log.debug(String.format("URL:%sTOPIC:%s", ueburl, topic));
-            return new CambriaClientBuilders.PublisherBuilder().usingHosts(ueburl).onTopic(topic)
-                    .logSendFailuresAfter(5)
-                    .build();
-        }
-    }
-}
diff --git a/src/main/java/org/onap/dcae/commonFunction/CommonStartup.java b/src/main/java/org/onap/dcae/commonFunction/CommonStartup.java
index b60104ea..3469531e 100644
--- a/src/main/java/org/onap/dcae/commonFunction/CommonStartup.java
+++ b/src/main/java/org/onap/dcae/commonFunction/CommonStartup.java
@@ -7,9 +7,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

- * 

+ *

  *      http://www.apache.org/licenses/LICENSE-2.0

- * 

+ *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

@@ -39,15 +39,6 @@ import com.github.fge.jsonschema.core.report.ProcessingMessage;
 import com.github.fge.jsonschema.core.report.ProcessingReport;

 import com.github.fge.jsonschema.main.JsonSchema;

 import com.github.fge.jsonschema.main.JsonSchemaFactory;

-

-import org.apache.catalina.LifecycleException;

-import org.json.JSONArray;

-import org.json.JSONException;

-import org.json.JSONObject;

-import org.onap.dcae.restapi.RestfulCollectorServlet;

-import org.slf4j.Logger;

-import org.slf4j.LoggerFactory;

-

 import java.io.IOException;

 import java.net.URL;

 import java.nio.file.Files;

@@ -58,185 +49,193 @@ import java.util.Map;
 import java.util.concurrent.ExecutorService;

 import java.util.concurrent.Executors;

 import java.util.concurrent.LinkedBlockingQueue;

+import org.apache.catalina.LifecycleException;

+import org.json.JSONArray;

+import org.json.JSONException;

+import org.json.JSONObject;

+import org.onap.dcae.commonFunction.event.publishing.DMaaPConfigurationParser;

+import org.onap.dcae.commonFunction.event.publishing.EventPublisher;

+import org.onap.dcae.restapi.RestfulCollectorServlet;

+import org.slf4j.Logger;

+import org.slf4j.LoggerFactory;

 

 public class CommonStartup extends NsaBaseEndpoint implements Runnable {

 

-	private static final String KCONFIG = "c";

-	private static final String KSETTING_PORT = "collector.service.port";

-	private static final int KDEFAULT_PORT = 8080;

-	private static final String KSETTING_SECUREPORT = "collector.service.secure.port";

-	private static final int KDEFAULT_SECUREPORT = -1;

-	private static final String KSETTING_KEYSTOREPASSFILE = "collector.keystore.passwordfile";

-	private static final String KDEFAULT_KEYSTOREPASSFILE = "../etc/passwordfile";

-	private static final String KSETTING_KEYSTOREFILE = "collector.keystore.file.location";

-	private static final String KDEFAULT_KEYSTOREFILE = "../etc/keystore";

-	private static final String KSETTING_KEYALIAS = "collector.keystore.alias";

-	private static final String KDEFAULT_KEYALIAS = "tomcat";

-	private static final String KSETTING_DMAAPCONFIGS = "collector.dmaapfile";

-	private static final String[] KDEFAULT_DMAAPCONFIGS = new String[] { "/etc/DmaapConfig.json" };

-	private static final String KSETTING_SCHEMAVALIDATOR = "collector.schema.checkflag";

-	private static final int KDEFAULT_SCHEMAVALIDATOR = -1;

-	private static final String KSETTING_SCHEMAFILE = "collector.schema.file";

-	private static final String KDEFAULT_SCHEMAFILE = "{\"v5\":\"./etc/CommonEventFormat_28.3.json\"}";

-	private static final String KSETTING_DMAAPSTREAMID = "collector.dmaap.streamid";

-	private static final String KSETTING_AUTHFLAG = "header.authflag";

-	private static final int KDEFAULT_AUTHFLAG = 0;

-	private static final String KSETTING_EVENTTRANSFORMFLAG = "event.transform.flag";

-	private static final int KDEFAULT_EVENTTRANSFORMFLAG = 1;

-	private static final Logger metriclog = LoggerFactory.getLogger("com.att.ecomp.metrics");

-	public static final Logger inlog = LoggerFactory.getLogger("org.onap.dcae.commonFunction.input");

-	static final Logger oplog = LoggerFactory.getLogger("org.onap.dcae.commonFunction.output");

-	public static final Logger eplog = LoggerFactory.getLogger("org.onap.dcae.commonFunction.error");

-

-	public static final String KSETTING_AUTHLIST = "header.authlist";

-	static final int KDEFAULT_MAXQUEUEDEVENTS = 1024 * 4;

-	public static int schemaValidatorflag = -1;

-	public static int authflag = 1;

-	static int eventTransformFlag = 1;

-	public static JSONObject schemaFileJson;

-	static String cambriaConfigFile;

-	public static String streamID;

-

-	static LinkedBlockingQueue<JSONObject> fProcessingInputQueue;

-	private static ApiServer fTomcatServer = null;

-	private static final Logger log = LoggerFactory.getLogger(CommonStartup.class);

-

-	private CommonStartup(rrNvReadable settings) throws loadException, IOException, rrNvReadable.missingReqdSetting {

-		final List<ApiServerConnector> connectors = new LinkedList<>();

-

-		if (settings.getInt(KSETTING_PORT, KDEFAULT_PORT) > 0) {

-			connectors.add(new ApiServerConnector.Builder(settings.getInt(KSETTING_PORT, KDEFAULT_PORT)).secure(false)

-					.build());

-		}

-

-		final int securePort = settings.getInt(KSETTING_SECUREPORT, KDEFAULT_SECUREPORT);

-		final String keystoreFile = settings.getString(KSETTING_KEYSTOREFILE, KDEFAULT_KEYSTOREFILE);

-		final String keystorePasswordFile = settings.getString(KSETTING_KEYSTOREPASSFILE, KDEFAULT_KEYSTOREPASSFILE);

-		final String keyAlias = settings.getString(KSETTING_KEYALIAS, KDEFAULT_KEYALIAS);

-

-		if (securePort > 0) {

-			String keystorePassword = readFile(keystorePasswordFile);

-			connectors.add(new ApiServerConnector.Builder(securePort).secure(true)

-					.keystorePassword(keystorePassword).keystoreFile(keystoreFile).keyAlias(keyAlias).build());

-

-		}

-

-		schemaValidatorflag = settings.getInt(KSETTING_SCHEMAVALIDATOR, KDEFAULT_SCHEMAVALIDATOR);

-		if (schemaValidatorflag > 0) {

-			String schemaFile = settings.getString(KSETTING_SCHEMAFILE, KDEFAULT_SCHEMAFILE);

-			schemaFileJson = new JSONObject(schemaFile);

-

-		}

-		authflag = settings.getInt(CommonStartup.KSETTING_AUTHFLAG, CommonStartup.KDEFAULT_AUTHFLAG);

-		String[] currentConfigFile = settings.getStrings(KSETTING_DMAAPCONFIGS, KDEFAULT_DMAAPCONFIGS);

-		cambriaConfigFile = currentConfigFile[0];

-		streamID = settings.getString(KSETTING_DMAAPSTREAMID, null);

-		eventTransformFlag = settings.getInt(KSETTING_EVENTTRANSFORMFLAG, KDEFAULT_EVENTTRANSFORMFLAG);

-

-		fTomcatServer = new ApiServer.Builder(connectors, new RestfulCollectorServlet(settings)).encodeSlashes(true)

-				.name("collector").build();

-	}

-

-	public static void main(String[] args) {

-		try {

-			final Map<String, String> argMap = NsaCommandLineUtil.processCmdLine(args, true);

-			final String config = NsaCommandLineUtil.getSetting(argMap, KCONFIG, "collector.properties");

-			final URL settingStream = DrumlinServlet.findStream(config, CommonStartup.class);

-

-			final nvReadableStack settings = new nvReadableStack();

-			settings.push(new nvPropertiesFile(settingStream));

-			settings.push(new nvReadableTable(argMap));

-

-			fProcessingInputQueue = new LinkedBlockingQueue<>(CommonStartup.KDEFAULT_MAXQUEUEDEVENTS);

-

-			VESLogger.setUpEcompLogging();

-

-			CommonStartup cs = new CommonStartup(settings);

-

-			Thread commonStartupThread = new Thread(cs);

-			commonStartupThread.start();

-

-			EventProcessor ep = new EventProcessor();

-			ExecutorService executor = Executors.newFixedThreadPool(20);

-			for (int i = 0; i < 20; ++i) {

-				executor.execute(ep);

-			}

-

-		} catch (loadException | missingReqdSetting | IOException e) {

-			CommonStartup.eplog.error("FATAL_STARTUP_ERROR" + e.getMessage());

-			throw new RuntimeException(e);

-		} catch (Exception e) {

-			System.err.println("Uncaught exception - " + e.getMessage());

-			CommonStartup.eplog.error("FATAL_ERROR" + e.getMessage());

-			e.printStackTrace(System.err);

-		}

-	}

-

-	public void run() {

-		try {

-			fTomcatServer.start();

-			fTomcatServer.await();

-		} catch (LifecycleException | IOException e) {

-			throw new RuntimeException(e);

-		}

-	}

-

-	public static class QueueFullException extends Exception {

-		private static final long serialVersionUID = 1L;

-	}

-

-	public static void handleEvents(JSONArray a) throws QueueFullException, JSONException {

-		CommonStartup.metriclog.info("EVENT_PUBLISH_START");

-		for (int i = 0; i < a.length(); i++) {

-			if (!fProcessingInputQueue.offer(a.getJSONObject(i))) {

-				throw new QueueFullException();

-			}

-		}

-		log.debug("CommonStartup.handleEvents:EVENTS has been published successfully!");

-		CommonStartup.metriclog.info("EVENT_PUBLISH_END");

-	}

-

-	private static String readFile(String path) throws IOException {

-		byte[] encoded = Files.readAllBytes(Paths.get(path));

-		String pwd = new String(encoded);

-		return pwd.substring(0, pwd.length() - 1);

-	}

-

-	public static String validateAgainstSchema(String jsonData, String jsonSchema) {

-		ProcessingReport report;

-		String result = "false";

-

-		try {

-			log.trace("Schema validation for event:" + jsonData);

-			JsonNode schemaNode = JsonLoader.fromString(jsonSchema);

-			JsonNode data = JsonLoader.fromString(jsonData);

-			JsonSchemaFactory factory = JsonSchemaFactory.byDefault();

-			JsonSchema schema = factory.getJsonSchema(schemaNode);

-			report = schema.validate(data);

-		} catch (JsonParseException e) {

-			log.error("validateAgainstSchema:JsonParseException for event:" + jsonData);

-			return e.getMessage();

-		} catch (ProcessingException e) {

-			log.error("validateAgainstSchema:Processing exception for event:" + jsonData);

-			return e.getMessage();

-		} catch (IOException e) {

-			log.error(

-					"validateAgainstSchema:IO exception; something went wrong trying to read json data for event:" + jsonData);

-			return e.getMessage();

-		}

-		if (report != null) {

-			for (ProcessingMessage pm : report) {

-				log.trace("Processing Message: " + pm.getMessage());

-			}

-			result = String.valueOf(report.isSuccess());

-		}

-		try {

-			log.debug("Validation Result:" + result + " Validation report:" + report);

-		} catch (NullPointerException e) {

-			log.error("validateAgainstSchema:NullpointerException on report");

-		}

-		return result;

-	}

+    private static final String KCONFIG = "c";

+    private static final String KSETTING_PORT = "collector.service.port";

+    private static final int KDEFAULT_PORT = 8080;

+    private static final String KSETTING_SECUREPORT = "collector.service.secure.port";

+    private static final int KDEFAULT_SECUREPORT = -1;

+    private static final String KSETTING_KEYSTOREPASSFILE = "collector.keystore.passwordfile";

+    private static final String KDEFAULT_KEYSTOREPASSFILE = "../etc/passwordfile";

+    private static final String KSETTING_KEYSTOREFILE = "collector.keystore.file.location";

+    private static final String KDEFAULT_KEYSTOREFILE = "../etc/keystore";

+    private static final String KSETTING_KEYALIAS = "collector.keystore.alias";

+    private static final String KDEFAULT_KEYALIAS = "tomcat";

+    private static final String KSETTING_DMAAPCONFIGS = "collector.dmaapfile";

+    private static final String[] KDEFAULT_DMAAPCONFIGS = new String[]{"/etc/DmaapConfig.json"};

+    private static final String KSETTING_SCHEMAVALIDATOR = "collector.schema.checkflag";

+    private static final int KDEFAULT_SCHEMAVALIDATOR = -1;

+    private static final String KSETTING_SCHEMAFILE = "collector.schema.file";

+    private static final String KDEFAULT_SCHEMAFILE = "{\"v5\":\"./etc/CommonEventFormat_28.3.json\"}";

+    private static final String KSETTING_DMAAPSTREAMID = "collector.dmaap.streamid";

+    private static final String KSETTING_AUTHFLAG = "header.authflag";

+    private static final int KDEFAULT_AUTHFLAG = 0;

+    private static final String KSETTING_EVENTTRANSFORMFLAG = "event.transform.flag";

+    private static final int KDEFAULT_EVENTTRANSFORMFLAG = 1;

+    private static final Logger metriclog = LoggerFactory.getLogger("com.att.ecomp.metrics");

+    public static final Logger inlog = LoggerFactory.getLogger("org.onap.dcae.commonFunction.input");

+    static final Logger oplog = LoggerFactory.getLogger("org.onap.dcae.commonFunction.output");

+    public static final Logger eplog = LoggerFactory.getLogger("org.onap.dcae.commonFunction.error");

+

+    public static final String KSETTING_AUTHLIST = "header.authlist";

+    static final int KDEFAULT_MAXQUEUEDEVENTS = 1024 * 4;

+    public static int schemaValidatorflag = -1;

+    public static int authflag = 1;

+    static int eventTransformFlag = 1;

+    public static JSONObject schemaFileJson;

+    static String cambriaConfigFile;

+    public static String streamID;

+

+    static LinkedBlockingQueue<JSONObject> fProcessingInputQueue;

+    private static ApiServer fTomcatServer = null;

+    private static final Logger log = LoggerFactory.getLogger(CommonStartup.class);

+

+    private CommonStartup(rrNvReadable settings) throws loadException, IOException, rrNvReadable.missingReqdSetting {

+        final List<ApiServerConnector> connectors = new LinkedList<>();

+

+        if (settings.getInt(KSETTING_PORT, KDEFAULT_PORT) > 0) {

+            connectors.add(new ApiServerConnector.Builder(settings.getInt(KSETTING_PORT, KDEFAULT_PORT)).secure(false)

+                               .build());

+        }

+

+        final int securePort = settings.getInt(KSETTING_SECUREPORT, KDEFAULT_SECUREPORT);

+        final String keystoreFile = settings.getString(KSETTING_KEYSTOREFILE, KDEFAULT_KEYSTOREFILE);

+        final String keystorePasswordFile = settings.getString(KSETTING_KEYSTOREPASSFILE, KDEFAULT_KEYSTOREPASSFILE);

+        final String keyAlias = settings.getString(KSETTING_KEYALIAS, KDEFAULT_KEYALIAS);

+

+        if (securePort > 0) {

+            String keystorePassword = readFile(keystorePasswordFile);

+            connectors.add(new ApiServerConnector.Builder(securePort).secure(true)

+                               .keystorePassword(keystorePassword).keystoreFile(keystoreFile).keyAlias(keyAlias).build());

+

+        }

+

+        schemaValidatorflag = settings.getInt(KSETTING_SCHEMAVALIDATOR, KDEFAULT_SCHEMAVALIDATOR);

+        if (schemaValidatorflag > 0) {

+            String schemaFile = settings.getString(KSETTING_SCHEMAFILE, KDEFAULT_SCHEMAFILE);

+            schemaFileJson = new JSONObject(schemaFile);

+

+        }

+        authflag = settings.getInt(CommonStartup.KSETTING_AUTHFLAG, CommonStartup.KDEFAULT_AUTHFLAG);

+        String[] currentConfigFile = settings.getStrings(KSETTING_DMAAPCONFIGS, KDEFAULT_DMAAPCONFIGS);

+        cambriaConfigFile = currentConfigFile[0];

+        streamID = settings.getString(KSETTING_DMAAPSTREAMID, null);

+        eventTransformFlag = settings.getInt(KSETTING_EVENTTRANSFORMFLAG, KDEFAULT_EVENTTRANSFORMFLAG);

+

+        fTomcatServer = new ApiServer.Builder(connectors, new RestfulCollectorServlet(settings)).encodeSlashes(true)

+            .name("collector").build();

+    }

+

+    public static void main(String[] args) {

+        try {

+            final Map<String, String> argMap = NsaCommandLineUtil.processCmdLine(args, true);

+            final String config = NsaCommandLineUtil.getSetting(argMap, KCONFIG, "collector.properties");

+            final URL settingStream = DrumlinServlet.findStream(config, CommonStartup.class);

+

+            final nvReadableStack settings = new nvReadableStack();

+            settings.push(new nvPropertiesFile(settingStream));

+            settings.push(new nvReadableTable(argMap));

+

+            fProcessingInputQueue = new LinkedBlockingQueue<>(CommonStartup.KDEFAULT_MAXQUEUEDEVENTS);

+

+            VESLogger.setUpEcompLogging();

+

+            CommonStartup cs = new CommonStartup(settings);

+

+            Thread commonStartupThread = new Thread(cs);

+            commonStartupThread.start();

+

+            EventProcessor ep = new EventProcessor(EventPublisher.createPublisher(oplog,

+                                                                                  DMaaPConfigurationParser

+                                                                                      .parseToDomainMapping(Paths.get(cambriaConfigFile))

+                                                                                      .get()));

+            ExecutorService executor = Executors.newFixedThreadPool(20);

+            for (int i = 0; i < 20; ++i) {

+                executor.execute(ep);

+            }

+        } catch (Exception e) {

+            CommonStartup.eplog.error("Fatal error during application startup", e);

+            throw new RuntimeException(e);

+        }

+    }

+

+    public void run() {

+        try {

+            fTomcatServer.start();

+            fTomcatServer.await();

+        } catch (LifecycleException | IOException e) {

+            throw new RuntimeException(e);

+        }

+    }

+

+    public static class QueueFullException extends Exception {

+

+        private static final long serialVersionUID = 1L;

+    }

+

+    public static void handleEvents(JSONArray a) throws QueueFullException, JSONException {

+        CommonStartup.metriclog.info("EVENT_PUBLISH_START");

+        for (int i = 0; i < a.length(); i++) {

+            if (!fProcessingInputQueue.offer(a.getJSONObject(i))) {

+                throw new QueueFullException();

+            }

+        }

+        log.debug("CommonStartup.handleEvents:EVENTS has been published successfully!");

+        CommonStartup.metriclog.info("EVENT_PUBLISH_END");

+    }

+

+    private static String readFile(String path) throws IOException {

+        byte[] encoded = Files.readAllBytes(Paths.get(path));

+        String pwd = new String(encoded);

+        return pwd.substring(0, pwd.length() - 1);

+    }

+

+    public static String validateAgainstSchema(String jsonData, String jsonSchema) {

+        ProcessingReport report;

+        String result = "false";

+

+        try {

+            log.trace("Schema validation for event:" + jsonData);

+            JsonNode schemaNode = JsonLoader.fromString(jsonSchema);

+            JsonNode data = JsonLoader.fromString(jsonData);

+            JsonSchemaFactory factory = JsonSchemaFactory.byDefault();

+            JsonSchema schema = factory.getJsonSchema(schemaNode);

+            report = schema.validate(data);

+        } catch (JsonParseException e) {

+            log.error("validateAgainstSchema:JsonParseException for event:" + jsonData);

+            return e.getMessage();

+        } catch (ProcessingException e) {

+            log.error("validateAgainstSchema:Processing exception for event:" + jsonData);

+            return e.getMessage();

+        } catch (IOException e) {

+            log.error(

+                "validateAgainstSchema:IO exception; something went wrong trying to read json data for event:" + jsonData);

+            return e.getMessage();

+        }

+        if (report != null) {

+            for (ProcessingMessage pm : report) {

+                log.trace("Processing Message: " + pm.getMessage());

+            }

+            result = String.valueOf(report.isSuccess());

+        }

+        try {

+            log.debug("Validation Result:" + result + " Validation report:" + report);

+        } catch (NullPointerException e) {

+            log.error("validateAgainstSchema:NullpointerException on report");

+        }

+        return result;

+    }

 

 

 }

diff --git a/src/main/java/org/onap/dcae/commonFunction/DmaapPropertyReader.java b/src/main/java/org/onap/dcae/commonFunction/DmaapPropertyReader.java
deleted file mode 100644
index 0ee1e434..00000000
--- a/src/main/java/org/onap/dcae/commonFunction/DmaapPropertyReader.java
+++ /dev/null
@@ -1,143 +0,0 @@
-/*-
- * ============LICENSE_START=======================================================
- * PROJECT
- * ================================================================================
- * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.dcae.commonFunction;
-
-import com.google.common.collect.Lists;
-import com.google.common.collect.Maps;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.io.IOException;
-import java.net.MalformedURLException;
-import java.net.URL;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.stream.Collectors;
-
-public class DmaapPropertyReader {
-
-
-    private static final Logger log = LoggerFactory.getLogger(DmaapPropertyReader.class);
-    private static final String CAMBRIA_TOPIC_KEY = "cambria.topic";
-    private static final String CAMBRIA_HOSTS_KEY = "cambria.hosts";
-    private static final String CAMBRIA_URL_KEY = "cambria.url";
-    private static final List<String> LEGACY_CHANNEL_MANDATORY_PARAMS = Lists.newArrayList(CAMBRIA_TOPIC_KEY, CAMBRIA_HOSTS_KEY, CAMBRIA_URL_KEY, "basicAuthPassword", "basicAuthUsername");
-    private static DmaapPropertyReader instance = null;
-    private final Map<String, String> dmaapProperties;
-
-    public DmaapPropertyReader(String cambriaConfigFilePath) {
-        this.dmaapProperties = DmaapPropertyReader.getProcessedDmaapProperties(cambriaConfigFilePath);
-    }
-
-    public Map<String, String> getDmaapProperties() {
-        return dmaapProperties;
-    }
-
-    public static synchronized DmaapPropertyReader getInstance(String channelConfig) {
-        if (instance == null) {
-            instance = new DmaapPropertyReader(channelConfig);
-        }
-        return instance;
-    }
-
-    public String getKeyValue(String hashKey) {
-        return dmaapProperties.get(hashKey);
-    }
-
-    private static Map<String, String> getProcessedDmaapProperties(String configFilePath) {
-        Map<String, String> transformedDmaapProperties = new HashMap<>();
-        try {
-            AnyNode root = AnyNode.parse(configFilePath);
-            if (isInLegacyFormat(root)) {
-                transformedDmaapProperties = getLegacyDmaapPropertiesWithChannels(root.get("channels"));
-            } else {
-                transformedDmaapProperties = getDmaapPropertiesWithInfoData(root);
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-        return transformedDmaapProperties;
-    }
-
-    private static boolean isInLegacyFormat(AnyNode root) {
-        return root.hasKey("channels");
-    }
-
-    private static Map<String, String> getLegacyDmaapPropertiesWithChannels(AnyNode channelsNode) {
-        return channelsNode.asList().stream()
-                .map(DmaapPropertyReader::getTransformedMandatoryChannelProperties)
-                .flatMap(m -> m.entrySet().stream())
-                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
-    }
-
-    private static Map<String, String> getTransformedMandatoryChannelProperties(AnyNode channel) {
-        String prefix = channel.get("name").asString() + ".";
-        return channel.asMap().entrySet().stream().filter(el -> LEGACY_CHANNEL_MANDATORY_PARAMS.contains(el.getKey()) && !Objects.equals(el.getKey(), "name"))
-                .collect(Collectors.toMap(k -> prefix + k.getKey(), v -> v.getValue().asString().replace("\"", "")));
-    }
-
-    private static Map<String, String> getDmaapPropertiesWithInfoData(AnyNode root) {
-        return root.asMap().entrySet().stream()
-                .map(DmaapPropertyReader::getTransformedMandatoryInfoProperties).flatMap(m -> m.entrySet().stream())
-                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
-    }
-
-    private static Map<String, String> getTransformedMandatoryInfoProperties(Map.Entry<String, AnyNode> el) {
-        String prefix = el.getKey() + ".";
-        AnyNode val = el.getValue();
-        Map<String, String> map = Maps.newHashMap();
-        map.put(prefix + "basicAuthUsername", val.getAsOptional("aaf_username").orElse(AnyNode.nullValue()).asString().replace("\"", ""));
-        map.put(prefix + "basicAuthPassword", val.getAsOptional("aaf_password").orElse(AnyNode.nullValue()).asString().replace("\"", ""));
-        map.putAll(getParamsFromDmaapInfoTopicUrl(prefix, val.get("dmaap_info").get("topic_url").asString().replace("\"", "")));
-        return map;
-    }
-
-    /***
-     * Dmaap url structure pub - https://<dmaaphostname>:<port>/events/
-     * <namespace>.<dmaapcluster>.<topic>, sub - https://<dmaaphostname>:
-     * <port>/events/<namespace>.<dmaapcluster>.<topic>/G1/u1";
-     *
-     * Onap url structure pub - http://<dmaaphostname>:<port>/<unauthenticated>.
-     * <topic>,
-     */
-    private static Map<String, String> getParamsFromDmaapInfoTopicUrl(String keyPrefix, String topicUrl) {
-        Map<String, String> topicUrlParts = Maps.newHashMap();
-        try {
-            URL url = new URL(topicUrl);
-            topicUrlParts.put(keyPrefix + CAMBRIA_URL_KEY, url.getAuthority());
-            String[] pathParts = url.getPath().split("/");
-            if (pathParts.length > 2 && "events".equals(pathParts[1])) {
-                // DCAE internal dmaap topic convention
-                topicUrlParts.put(keyPrefix + CAMBRIA_TOPIC_KEY, pathParts[2]);
-            } else {
-                // ONAP dmaap topic convention
-                topicUrlParts.put(keyPrefix + CAMBRIA_TOPIC_KEY, pathParts[2]);
-                topicUrlParts.put(keyPrefix + CAMBRIA_HOSTS_KEY, url.getHost());
-            }
-        } catch (MalformedURLException e) {
-            log.error("Invalid URL found under topic_url key!", e);
-            e.printStackTrace();
-        }
-        return topicUrlParts;
-    }
-}
\ No newline at end of file
diff --git a/src/main/java/org/onap/dcae/commonFunction/DmaapPublishers.java b/src/main/java/org/onap/dcae/commonFunction/DmaapPublishers.java
deleted file mode 100644
index a4c62719..00000000
--- a/src/main/java/org/onap/dcae/commonFunction/DmaapPublishers.java
+++ /dev/null
@@ -1,91 +0,0 @@
-/*-
- * ============LICENSE_START=======================================================
- * org.onap.dcaegen2.collectors.ves
- * ================================================================================
- * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
- * Copyright (C) 2018 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-package org.onap.dcae.commonFunction;
-
-import com.att.nsa.cambria.client.CambriaBatchingPublisher;
-import com.google.common.cache.CacheBuilder;
-import com.google.common.cache.CacheLoader;
-import com.google.common.cache.LoadingCache;
-import com.google.common.cache.RemovalListener;
-import java.io.IOException;
-import java.net.MalformedURLException;
-import java.security.GeneralSecurityException;
-import java.util.List;
-import java.util.concurrent.TimeUnit;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-class DmaapPublishers {
-
-    private static final Logger log = LoggerFactory.getLogger(DmaapPublishers.class);
-    private final LoadingCache<String, CambriaBatchingPublisher> publishers;
-
-    private DmaapPublishers(
-            LoadingCache<String, CambriaBatchingPublisher> publishers) {
-        this.publishers = publishers;
-    }
-
-    static DmaapPublishers create() {
-        return create(new CambriaPublisherFactory());
-    }
-
-    static DmaapPublishers create(final CambriaPublisherFactory publisherFactory) {
-        final LoadingCache<String, CambriaBatchingPublisher> cache = CacheBuilder.<String, CambriaBatchingPublisher>newBuilder()
-                .removalListener((RemovalListener<String, CambriaBatchingPublisher>) notification -> {
-                    if (notification.getValue() != null) {
-                        onCacheItemInvalidated(notification.getValue());
-                    }
-                })
-                .build(new CacheLoader<String, CambriaBatchingPublisher>() {
-                    @Override
-                    public CambriaBatchingPublisher load(String streamId)
-                            throws MalformedURLException, GeneralSecurityException {
-                        try {
-                            return publisherFactory.createCambriaPublisher(streamId);
-                        } catch (MalformedURLException | GeneralSecurityException e) {
-                            log.error("CambriaClientBuilders connection reader exception : streamID - " + streamId + " "
-                                    + e.getMessage());
-                            throw e;
-                        }
-                    }
-                });
-        return new DmaapPublishers(cache);
-    }
-
-    CambriaBatchingPublisher getByStreamId(String streamId) {
-        return publishers.getUnchecked(streamId);
-    }
-
-    void closeByStreamId(String streamId) {
-        publishers.invalidate(streamId);
-    }
-
-    private static void onCacheItemInvalidated(CambriaBatchingPublisher pub) {
-        try {
-            final List<?> stuck = pub.close(20, TimeUnit.SECONDS);
-            if (!stuck.isEmpty()) {
-                log.error(stuck.size() + " messages unsent");
-            }
-        } catch (InterruptedException | IOException e) {
-            log.error("Caught Exception on Close event: {}", e);
-        }
-    }
-}
diff --git a/src/main/java/org/onap/dcae/commonFunction/EventProcessor.java b/src/main/java/org/onap/dcae/commonFunction/EventProcessor.java
index 06a27328..9d6ad360 100644
--- a/src/main/java/org/onap/dcae/commonFunction/EventProcessor.java
+++ b/src/main/java/org/onap/dcae/commonFunction/EventProcessor.java
@@ -27,6 +27,7 @@ import com.google.common.reflect.TypeToken;
 import com.google.gson.Gson;

 import java.util.Map;

 import org.json.JSONObject;

+import org.onap.dcae.commonFunction.event.publishing.EventPublisher;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 

@@ -52,8 +53,10 @@ class EventProcessor implements Runnable {
 

 	static Map<String, String[]> streamidHash = new HashMap<>();

 	public JSONObject event;

+    private EventPublisher eventPublisher;

 

-    EventProcessor() {

+    public EventProcessor(EventPublisher eventPublisher) {

+        this.eventPublisher = eventPublisher;

         streamidHash = parseStreamIdToStreamHashMapping(CommonStartup.streamID);

     }

 

@@ -128,7 +131,7 @@ class EventProcessor implements Runnable {
         for (String aStreamIdList : streamIdList) {

             log.info("Invoking publisher for streamId:" + aStreamIdList);

             this.overrideEvent();

-            EventPublisherHash.getInstance().sendEvent(event, aStreamIdList);

+            eventPublisher.sendEvent(event, aStreamIdList);

 

         }

     }

diff --git a/src/main/java/org/onap/dcae/commonFunction/EventPublisherHash.java b/src/main/java/org/onap/dcae/commonFunction/EventPublisherHash.java
deleted file mode 100644
index f3907126..00000000
--- a/src/main/java/org/onap/dcae/commonFunction/EventPublisherHash.java
+++ /dev/null
@@ -1,85 +0,0 @@
-/*-
- * ============LICENSE_START=======================================================
- * org.onap.dcaegen2.collectors.ves
- * ================================================================================
- * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
- * Copyright (C) 2018 Nokia. All rights reserved.
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.dcae.commonFunction;
-
-import com.att.nsa.cambria.client.CambriaBatchingPublisher;
-import com.att.nsa.clock.SaClock;
-import com.att.nsa.logging.LoggingContext;
-import com.att.nsa.logging.log4j.EcompFields;
-import com.google.common.annotations.VisibleForTesting;
-import java.io.IOException;
-import org.json.JSONObject;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-public class EventPublisherHash {
-
-    private static final String VES_UNIQUE_ID = "VESuniqueId";
-    private static final Logger log = LoggerFactory.getLogger(EventPublisherHash.class);
-    private static volatile EventPublisherHash instance = new EventPublisherHash(DmaapPublishers.create());
-    private final DmaapPublishers dmaapPublishers;
-
-    public static EventPublisherHash getInstance() {
-        return instance;
-    }
-
-    @VisibleForTesting
-    EventPublisherHash(DmaapPublishers dmaapPublishers) {
-        this.dmaapPublishers = dmaapPublishers;
-    }
-
-    void sendEvent(JSONObject event, String streamid) {
-        log.debug("EventPublisher.sendEvent: instance for publish is ready");
-        clearVesUniqueId(event);
-
-        try {
-            sendEventUsingCachedPublisher(streamid, event);
-        } catch (IOException | IllegalArgumentException e) {
-            log.error("Unable to publish event: {} streamID: {}. Exception: {}", event, streamid, e);
-            dmaapPublishers.closeByStreamId(streamid);
-        }
-    }
-
-    private void clearVesUniqueId(JSONObject event) {
-        if (event.has(VES_UNIQUE_ID)) {
-            String uuid = event.get(VES_UNIQUE_ID).toString();
-            LoggingContext localLC = VESLogger.getLoggingContextForThread(uuid);
-            localLC.put(EcompFields.kBeginTimestampMs, SaClock.now());
-            log.debug("Removing VESuniqueid object from event");
-            event.remove(VES_UNIQUE_ID);
-        }
-    }
-
-    private void sendEventUsingCachedPublisher(String streamid, JSONObject event) throws IOException {
-        int pendingMsgs = dmaapPublishers.getByStreamId(streamid).send("MyPartitionKey", event.toString());
-        if (pendingMsgs > 100) {
-            log.info("Pending Message Count=" + pendingMsgs);
-        }
-        log.info("pub.send invoked - no error");
-        CommonStartup.oplog.info(String.format("StreamID:%s Event Published:%s ", streamid, event));
-    }
-
-    @VisibleForTesting
-    CambriaBatchingPublisher getDmaapPublisher(String streamId) {
-        return dmaapPublishers.getByStreamId(streamId);
-    }
-}
diff --git a/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPConfigurationParser.java b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPConfigurationParser.java
new file mode 100644
index 00000000..bef14448
--- /dev/null
+++ b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPConfigurationParser.java
@@ -0,0 +1,108 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2018 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.commonFunction.event.publishing;
+
+import static io.vavr.API.List;
+import static io.vavr.API.Try;
+import static io.vavr.API.Tuple;
+import static io.vavr.API.unchecked;
+import static org.onap.dcae.commonFunction.event.publishing.VavrUtils.enhanceError;
+import static org.onap.dcae.commonFunction.event.publishing.VavrUtils.f;
+
+import io.vavr.collection.List;
+import io.vavr.collection.Map;
+import io.vavr.control.Option;
+import io.vavr.control.Try;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.onap.dcae.commonFunction.AnyNode;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+@SuppressWarnings("mapFailure takes a generic varargs, unchecked because of Javas type system limitation, actually safe to do")
+public final class DMaaPConfigurationParser {
+
+    public static Try<Map<String, PublisherConfig>> parseToDomainMapping(Path configLocation) {
+        return readFromFile(configLocation)
+            .flatMap(DMaaPConfigurationParser::toJSON)
+            .flatMap(DMaaPConfigurationParser::toConfigMap);
+    }
+
+    private static Try<String> readFromFile(Path configLocation) {
+        return Try(() -> new String(Files.readAllBytes(configLocation)))
+            .mapFailure(enhanceError(f("Could not read DMaaP configuration from location: '%s'", configLocation)));
+    }
+
+    private static Try<AnyNode> toJSON(String config) {
+        return Try(() -> AnyNode.fromString(config))
+            .mapFailure(enhanceError(f("DMaaP configuration '%s' is not a valid JSON document", config)));
+    }
+
+    private static Try<Map<String, PublisherConfig>> toConfigMap(AnyNode config) {
+        return Try(() -> usesLegacyFormat(config) ? parseLegacyFormat(config) : parseNewFormat(config))
+            .mapFailure(enhanceError(
+                f("Parsing DMaaP configuration: '%s' failed, probably it is in unexpected format", config)));
+    }
+
+    private static boolean usesLegacyFormat(AnyNode dMaaPConfig) {
+        return dMaaPConfig.has("channels");
+    }
+
+    private static Map<String, PublisherConfig> parseLegacyFormat(AnyNode root) {
+        return root.get("channels").toList().toMap(
+            channel -> channel.get("name").toString(),
+            channel -> {
+                String destinationsStr = channel.getAsOption("cambria.url")
+                    .getOrElse(channel.getAsOption("cambria.hosts").get())
+                    .toString();
+                String topic = channel.get("cambria.topic").toString();
+                Option<String> maybeUser = channel.getAsOption("basicAuthUsername").map(AnyNode::toString);
+                Option<String> maybePassword = channel.getAsOption("basicAuthPassword").map(AnyNode::toString);
+                List<String> destinations = List(destinationsStr.split(","));
+                return buildBasedOnAuth(maybeUser, maybePassword, topic, destinations);
+            });
+    }
+
+    private static Map<String, PublisherConfig> parseNewFormat(AnyNode root) {
+        return root.keys().toMap(
+            channelName -> channelName,
+            channelName -> {
+                AnyNode channelConfig = root.get(channelName);
+                Option<String> maybeUser = channelConfig.getAsOption("aaf_username").map(AnyNode::toString);
+                Option<String> maybePassword = channelConfig.getAsOption("aaf_password").map(AnyNode::toString);
+                URL topicURL = unchecked(
+                    () -> new URL(channelConfig.get("dmaap_info").get("topic_url").toString())).apply();
+                String[] pathSegments = topicURL.getPath().substring(1).split("/");
+                String topic = pathSegments[1];
+                String destination = "events".equals(pathSegments[0]) ? topicURL.getAuthority() : topicURL.getHost();
+                List<String> destinations = List(destination);
+                return buildBasedOnAuth(maybeUser, maybePassword, topic, destinations);
+            });
+    }
+
+    private static PublisherConfig buildBasedOnAuth(Option<String> maybeUser, Option<String> maybePassword,
+                                                    String topic, List<String> destinations) {
+        return maybeUser.flatMap(user -> maybePassword.map(password -> Tuple(user, password)))
+            .map(credentials -> new PublisherConfig(destinations, topic, credentials._1, credentials._2))
+            .getOrElse(new PublisherConfig(destinations, topic));
+    }
+}
diff --git a/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPEventPublisher.java b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPEventPublisher.java
new file mode 100644
index 00000000..fd9b3ae1
--- /dev/null
+++ b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPEventPublisher.java
@@ -0,0 +1,99 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2018 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.dcae.commonFunction.event.publishing;
+
+import static org.onap.dcae.commonFunction.event.publishing.VavrUtils.f;
+
+import com.att.nsa.cambria.client.CambriaBatchingPublisher;
+import com.att.nsa.clock.SaClock;
+import com.att.nsa.logging.LoggingContext;
+import com.att.nsa.logging.log4j.EcompFields;
+import io.vavr.collection.Map;
+import io.vavr.control.Try;
+import java.io.IOException;
+import org.json.JSONObject;
+import org.onap.dcae.commonFunction.VESLogger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+class DMaaPEventPublisher implements EventPublisher {
+    private static final int PENDING_MESSAGE_LOG_THRESHOLD = 100;
+    private static final String VES_UNIQUE_ID = "VESuniqueId";
+    private static final Logger log = LoggerFactory.getLogger(DMaaPEventPublisher.class);
+    private final DMaaPPublishersCache publishersCache;
+    private final Logger outputLogger;
+
+    DMaaPEventPublisher(DMaaPPublishersCache DMaaPPublishersCache,
+                        Logger outputLogger) {
+        this.publishersCache = DMaaPPublishersCache;
+        this.outputLogger = outputLogger;
+    }
+
+    @Override
+    public void sendEvent(JSONObject event, String domain) {
+        clearVesUniqueIdFromEvent(event);
+        publishersCache.getPublisher(domain)
+            .onEmpty(() ->
+                log.warn(f("Could not find event publisher for domain: '%s', dropping message: '%s'", domain, event)))
+            .forEach(publisher -> sendEvent(event, domain, publisher));
+    }
+
+    @Override
+    public void reconfigure(Map<String, PublisherConfig> dMaaPConfig) {
+        publishersCache.reconfigure(dMaaPConfig);
+    }
+
+    private void sendEvent(JSONObject event, String domain, CambriaBatchingPublisher publisher) {
+        Try.run(() -> uncheckedSendEvent(event, domain, publisher))
+            .onFailure(exc -> closePublisher(event, domain, exc));
+    }
+
+    private void uncheckedSendEvent(JSONObject event, String domain, CambriaBatchingPublisher publisher)
+        throws IOException {
+        int pendingMsgs = publisher.send("MyPartitionKey", event.toString());
+        if (pendingMsgs > PENDING_MESSAGE_LOG_THRESHOLD) {
+            log.info("Pending messages count: " + pendingMsgs);
+        }
+        String infoMsg = f("Event: '%s' scheduled to be send asynchronously on domain: '%s'", event, domain);
+        log.info(infoMsg);
+        outputLogger.info(infoMsg);
+    }
+
+    private void closePublisher(JSONObject event, String domain, Throwable e) {
+        log.error(f("Unable to schedule event: '%s' on domain: '%s'. Closing publisher and dropping message.",
+            event, domain), e);
+        publishersCache.closePublisherFor(domain);
+    }
+
+    private void clearVesUniqueIdFromEvent(JSONObject event) {
+        if (event.has(VES_UNIQUE_ID)) {
+            String uuid = event.get(VES_UNIQUE_ID).toString();
+            LoggingContext localLC = VESLogger.getLoggingContextForThread(uuid);
+            localLC.put(EcompFields.kBeginTimestampMs, SaClock.now());
+            log.debug("Removing VESuniqueid object from event");
+            event.remove(VES_UNIQUE_ID);
+        }
+    }
+}
diff --git a/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPPublishersBuilder.java b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPPublishersBuilder.java
new file mode 100644
index 00000000..a7865a45
--- /dev/null
+++ b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPPublishersBuilder.java
@@ -0,0 +1,62 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2018 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.commonFunction.event.publishing;
+
+import static io.vavr.API.Try;
+import static org.onap.dcae.commonFunction.event.publishing.VavrUtils.enhanceError;
+import static org.onap.dcae.commonFunction.event.publishing.VavrUtils.f;
+
+import com.att.nsa.cambria.client.CambriaBatchingPublisher;
+import com.att.nsa.cambria.client.CambriaClientBuilders;
+import com.att.nsa.cambria.client.CambriaClientBuilders.PublisherBuilder;
+import io.vavr.control.Try;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+final class DMaaPPublishersBuilder {
+
+    @SuppressWarnings("mapFailure takes a generic varargs, unchecked because of Javas type system limitation, actually safe to do")
+    static Try<CambriaBatchingPublisher> buildPublisher(PublisherConfig config) {
+        return Try(() -> builder(config).build())
+            .mapFailure(enhanceError(f("DMaaP client builder throws exception for this configuration: '%s'", config)));
+    }
+
+    private static PublisherBuilder builder(PublisherConfig config) {
+        if (config.isSecured()) {
+            return authenticatedBuilder(config);
+        } else {
+            return unAuthenticatedBuilder(config);
+        }
+    }
+
+    private static PublisherBuilder authenticatedBuilder(PublisherConfig config) {
+        return unAuthenticatedBuilder(config)
+            .usingHttps()
+            .authenticatedByHttp(config.userName().get(), config.password().get());
+    }
+
+    private static PublisherBuilder unAuthenticatedBuilder(PublisherConfig config) {
+        return new CambriaClientBuilders.PublisherBuilder()
+            .usingHosts(config.destinations().mkString(","))
+            .onTopic(config.topic())
+            .logSendFailuresAfter(5);
+    }
+}
diff --git a/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPPublishersCache.java b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPPublishersCache.java
new file mode 100644
index 00000000..102d2774
--- /dev/null
+++ b/src/main/java/org/onap/dcae/commonFunction/event/publishing/DMaaPPublishersCache.java
@@ -0,0 +1,124 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2018 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.commonFunction.event.publishing;
+
+import static io.vavr.API.Option;
+import static org.onap.dcae.commonFunction.event.publishing.VavrUtils.f;
+
+import com.att.nsa.cambria.client.CambriaBatchingPublisher;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.cache.RemovalListener;
+import com.google.common.cache.RemovalNotification;
+import io.vavr.collection.Map;
+import io.vavr.control.Option;
+import java.io.IOException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import javax.annotation.Nonnull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+class DMaaPPublishersCache {
+
+    private static final Logger log = LoggerFactory.getLogger(DMaaPPublishersCache.class);
+    private final LoadingCache<String, CambriaBatchingPublisher> publishersCache;
+    private AtomicReference<Map<String, PublisherConfig>> dMaaPConfiguration;
+
+    DMaaPPublishersCache(Map<String, PublisherConfig> dMaaPConfiguration) {
+        this.dMaaPConfiguration = new AtomicReference<>(dMaaPConfiguration);
+        this.publishersCache = CacheBuilder.newBuilder()
+            .removalListener(new OnPublisherRemovalListener())
+            .build(new CambriaPublishersCacheLoader());
+    }
+
+    DMaaPPublishersCache(CambriaPublishersCacheLoader dMaaPPublishersCacheLoader,
+                         OnPublisherRemovalListener onPublisherRemovalListener,
+                         Map<String, PublisherConfig> dMaaPConfiguration) {
+        this.dMaaPConfiguration = new AtomicReference<>(dMaaPConfiguration);
+        this.publishersCache = CacheBuilder.newBuilder()
+            .removalListener(onPublisherRemovalListener)
+            .build(dMaaPPublishersCacheLoader);
+    }
+
+    Option<CambriaBatchingPublisher> getPublisher(String streamID) {
+        try {
+            return Option(publishersCache.getUnchecked(streamID));
+        } catch (Exception e) {
+            log.warn("Could not create / load Cambria Publisher for streamID", e);
+            return Option.none();
+        }
+    }
+
+    void closePublisherFor(String streamId) {
+        publishersCache.invalidate(streamId);
+    }
+
+    synchronized void reconfigure(Map<String, PublisherConfig> newConfig) {
+        Map<String, PublisherConfig> currentConfig = dMaaPConfiguration.get();
+        Map<String, PublisherConfig> removedConfigurations = currentConfig
+            .filterKeys(domain -> !newConfig.containsKey(domain));
+        Map<String, PublisherConfig> changedConfigurations = newConfig
+            .filterKeys(e -> currentConfig.containsKey(e) && !currentConfig.get(e).equals(newConfig.get(e)));
+        dMaaPConfiguration.set(newConfig);
+        removedConfigurations.merge(changedConfigurations).forEach(e -> publishersCache.invalidate(e._1));
+    }
+
+    static class OnPublisherRemovalListener implements RemovalListener<String, CambriaBatchingPublisher> {
+
+        @Override
+        public void onRemoval(@Nonnull RemovalNotification<String, CambriaBatchingPublisher> notification) {
+            CambriaBatchingPublisher publisher = notification.getValue();
+            if (publisher != null) { // The value might get Garbage Collected at this moment, regardless of @Nonnull
+                try {
+                    int timeout = 20;
+                    TimeUnit unit = TimeUnit.SECONDS;
+                    java.util.List<?> stuck = publisher.close(timeout, unit);
+                    if (!stuck.isEmpty()) {
+                        log.error(f("Publisher got stuck and did not manage to close in '%s' '%s', "
+                            + "%s messages were dropped", stuck.size(), timeout, unit));
+                    }
+                } catch (InterruptedException | IOException e) {
+                    log.error("Could not close Cambria publisher, some messages might have been dropped", e);
+                }
+            }
+        }
+    }
+
+    class CambriaPublishersCacheLoader extends CacheLoader<String, CambriaBatchingPublisher> {
+
+        @Override
+        public CambriaBatchingPublisher load(@Nonnull String domain) {
+            return dMaaPConfiguration.get()
+                .get(domain)
+                .toTry(() -> new RuntimeException(
+                    f("DMaaP configuration contains no configuration for domain: '%s'", domain)))
+                .flatMap(DMaaPPublishersBuilder::buildPublisher)
+                .get();
+        }
+    }
+
+}
diff --git a/src/main/java/org/onap/dcae/commonFunction/event/publishing/EventPublisher.java b/src/main/java/org/onap/dcae/commonFunction/event/publishing/EventPublisher.java
new file mode 100644
index 00000000..9cd718f8
--- /dev/null
+++ b/src/main/java/org/onap/dcae/commonFunction/event/publishing/EventPublisher.java
@@ -0,0 +1,38 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2018 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.commonFunction.event.publishing;
+
+import io.vavr.collection.Map;
+import org.json.JSONObject;
+import org.slf4j.Logger;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+public interface EventPublisher {
+
+    static EventPublisher createPublisher(Logger outputLogger, Map<String, PublisherConfig> dMaaPConfig) {
+        return new DMaaPEventPublisher(new DMaaPPublishersCache(dMaaPConfig), outputLogger);
+    }
+
+    void sendEvent(JSONObject event, String domain);
+
+    void reconfigure(Map<String, PublisherConfig> dMaaPConfig);
+}
diff --git a/src/main/java/org/onap/dcae/commonFunction/event/publishing/PublisherConfig.java b/src/main/java/org/onap/dcae/commonFunction/event/publishing/PublisherConfig.java
new file mode 100644
index 00000000..4a056778
--- /dev/null
+++ b/src/main/java/org/onap/dcae/commonFunction/event/publishing/PublisherConfig.java
@@ -0,0 +1,98 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2018 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.commonFunction.event.publishing;
+
+import io.vavr.collection.List;
+import io.vavr.control.Option;
+import java.util.Objects;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+public final class PublisherConfig {
+
+    private final List<String> destinations;
+    private final String topic;
+    private String userName;
+    private String password;
+
+    PublisherConfig(List<String> destinations, String topic) {
+        this.destinations = destinations;
+        this.topic = topic;
+    }
+
+    PublisherConfig(List<String> destinations, String topic, String userName, String password) {
+        this.destinations = destinations;
+        this.topic = topic;
+        this.userName = userName;
+        this.password = password;
+    }
+
+    List<String> destinations() {
+        return destinations;
+    }
+
+    String topic() {
+        return topic;
+    }
+
+    Option<String> userName() {
+        return Option.of(userName);
+    }
+
+    Option<String> password() {
+        return Option.of(password);
+    }
+
+    boolean isSecured() {
+        return userName().isDefined() && password().isDefined();
+    }
+
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        PublisherConfig that = (PublisherConfig) o;
+        return Objects.equals(destinations, that.destinations) &&
+            Objects.equals(topic, that.topic) &&
+            Objects.equals(userName, that.userName) &&
+            Objects.equals(password, that.password);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(destinations, topic, userName, password);
+    }
+
+    @Override
+    public String toString() {
+        return "PublisherConfig{" +
+            "destinations=" + destinations +
+            ", topic='" + topic + '\'' +
+            ", userName='" + userName + '\'' +
+            ", password='" + password + '\'' +
+            '}';
+    }
+}
diff --git a/src/main/java/org/onap/dcae/commonFunction/event/publishing/VavrUtils.java b/src/main/java/org/onap/dcae/commonFunction/event/publishing/VavrUtils.java
new file mode 100644
index 00000000..9bf3ef8c
--- /dev/null
+++ b/src/main/java/org/onap/dcae/commonFunction/event/publishing/VavrUtils.java
@@ -0,0 +1,51 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2018 Nokia. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.commonFunction.event.publishing;
+
+import static io.vavr.API.$;
+
+import io.vavr.API;
+import io.vavr.API.Match.Case;
+
+/**
+ * @author Pawel Szalapski (pawel.szalapski@nokia.com)
+ */
+final class VavrUtils {
+
+    private VavrUtils() {
+        // utils aggregator
+    }
+
+    /**
+     * Shortcut for 'string interpolation'
+     */
+    static String f(String msg, Object... args) {
+        return String.format(msg, args);
+    }
+
+    /**
+     * Wrap failure with a more descriptive message of what has failed and chain original cause. Used to provide a
+     * context for errors instead of raw exception.
+     */
+    static Case<Throwable, Throwable> enhanceError(String msg) {
+        return API.Case($(), e -> new RuntimeException(msg, e));
+    }
+
+}