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

1 files changed, 108 insertions, 0 deletions

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));
+    }
+}