Enhancement of AAI-traversal healthcheck

- enhance the EchoResponse endpoint to check for db connectivity when the myAction parameter is provided

Issue-ID: AAI-3547

Signed-off-by: Fiete Ostkamp <Fiete.Ostkamp@telekom.de>
Change-Id: I4d5686b63efd139b942cee0c222305a17d2a2497

2 files changed, 189 insertions, 75 deletions

diff --git a/aai-traversal/src/main/java/org/onap/aai/rest/util/AaiGraphChecker.java b/aai-traversal/src/main/java/org/onap/aai/rest/util/AaiGraphChecker.java
new file mode 100644
index 0000000..11b412d
--- /dev/null
+++ b/aai-traversal/src/main/java/org/onap/aai/rest/util/AaiGraphChecker.java
@@ -0,0 +1,103 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022 Bell Canada
+ * Modification Copyright (C) 2022 Deutsche Telekom SA
+ * ================================================================================
+ * 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.aai.rest.util;
+
+import java.util.Iterator;
+
+import org.janusgraph.core.JanusGraphException;
+import org.janusgraph.core.JanusGraphTransaction;
+import org.onap.aai.dbmap.AAIGraph;
+import org.onap.aai.logging.ErrorLogHelper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.config.ConfigurableBeanFactory;
+import org.springframework.context.annotation.Scope;
+import org.springframework.stereotype.Component;
+
+import com.google.common.collect.Iterators;
+
+/**
+ * Singleton class responsible to check that AAI service is able to connect to its back-end
+ * database.
+ */
+@Component
+@Scope(ConfigurableBeanFactory.SCOPE_SINGLETON)
+public class AaiGraphChecker {
+    private static final Logger LOGGER = LoggerFactory.getLogger(AaiGraphChecker.class);
+
+    private AaiGraphChecker() {
+    }
+
+    /**
+     * Checks whether a connection to the graph database can be made.
+     * 
+     * @return
+     *         <li>true, if database is available</li>
+     *         <li>false, if database is NOT available</li>
+     */
+    public Boolean isAaiGraphDbAvailable() {
+        Boolean dbAvailable;
+        JanusGraphTransaction transaction = null;
+        try {
+            transaction = AAIGraph.getInstance().getGraph().newTransaction();
+            final Iterator<?> vertexIterator = transaction.query().limit(1).vertices().iterator();
+            if (LOGGER.isDebugEnabled()) {
+                LOGGER.debug("Number of vertices retrieved while checking db: {}",
+                    Iterators.size(vertexIterator));
+            }
+            vertexIterator.hasNext();
+            LOGGER.debug("Database is available");
+            dbAvailable = Boolean.TRUE;
+        } catch (JanusGraphException e) {
+            String message = "Database is not available (after JanusGraph exception)";
+            ErrorLogHelper.logError("500", message + ": " + e.getMessage());
+            LOGGER.error(message, e);
+            dbAvailable = Boolean.FALSE;
+        } catch (Error e) {
+            // Following error occurs when aai resources is starting:
+            // - UnsatisfiedLinkError (for org.onap.aai.dbmap.AAIGraph$Helper instantiation)
+            // Following errors are raised when aai resources is starting and cassandra is not
+            // running:
+            // - ExceptionInInitializerError
+            // - NoClassDefFoundError (definition for org.onap.aai.dbmap.AAIGraph$Helper is not
+            // found)
+            String message = "Database is not available (after error)";
+            ErrorLogHelper.logError("500", message + ": " + e.getMessage());
+            LOGGER.error(message, e);
+            dbAvailable = Boolean.FALSE;
+        } catch (Exception e) {
+            String message = "Database availability can not be determined";
+            ErrorLogHelper.logError("500", message + ": " + e.getMessage());
+            LOGGER.error(message, e);
+            dbAvailable = null;
+        } finally {
+            if (transaction != null && !transaction.isClosed()) {
+                // check if transaction is open then closed instead of flag
+                try {
+                    transaction.rollback();
+                } catch (Exception e) {
+                    String message = "Exception occurred while closing transaction";
+                    LOGGER.error(message, e);
+                    ErrorLogHelper.logError("500", message + ": " + e.getMessage());
+                }
+            }
+        }
+        return dbAvailable;
+    }
+}
diff --git a/aai-traversal/src/main/java/org/onap/aai/rest/util/EchoResponse.java b/aai-traversal/src/main/java/org/onap/aai/rest/util/EchoResponse.java
index d0ba708..2e42e4c 100644
--- a/aai-traversal/src/main/java/org/onap/aai/rest/util/EchoResponse.java
+++ b/aai-traversal/src/main/java/org/onap/aai/rest/util/EchoResponse.java
@@ -8,7 +8,7 @@
  * 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
+ *    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,
@@ -36,85 +36,96 @@ import javax.ws.rs.core.Response.Status;
 import org.onap.aai.exceptions.AAIException;
 import org.onap.aai.logging.ErrorLogHelper;
 import org.onap.aai.restcore.RESTAPI;
+import org.springframework.stereotype.Component;
 
 /**
  * The Class EchoResponse.
  */
 @Path("/util")
+@Component
 public class EchoResponse extends RESTAPI {
 
-    protected static String authPolicyFunctionName = "util";
-
-    public static final String ECHO_PATH = "/echo";
-
-    /**
-     * Simple health-check API that echos back the X-FromAppId and X-TransactionId to clients.
-     * If there is a query string, a transaction gets logged into hbase, proving the application is
-     * connected to the data store.
-     * If there is no query string, no transacction logging is done to hbase.
-     *
-     * @param headers the headers
-     * @param req the req
-     * @param myAction if exists will cause transaction to be logged to hbase
-     * @return the response
-     */
-    @GET
-    @Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
-    @Path(ECHO_PATH)
-    public Response echoResult(@Context HttpHeaders headers, @Context HttpServletRequest req,
-        @QueryParam("action") String myAction) {
-        AAIException ex = null;
-        Response response;
-        String fromAppId;
-        String transId;
-
-        try {
-            fromAppId = getFromAppId(headers);
-            transId = getTransId(headers);
-        } catch (AAIException e) {
-            ArrayList<String> templateVars = new ArrayList<>();
-            templateVars.add("PUT uebProvider");
-            templateVars.add("addTopic");
-            return Response
-                .status(e.getErrorObject().getHTTPResponseCode()).entity(ErrorLogHelper
-                    .getRESTAPIErrorResponse(headers.getAcceptableMediaTypes(), e, templateVars))
-                .build();
-        }
-
-        try {
-
-            HashMap<AAIException, ArrayList<String>> exceptionList = new HashMap<>();
-
-            ArrayList<String> templateVars = new ArrayList<>();
-            templateVars.add(fromAppId);
-            templateVars.add(transId);
-
-            exceptionList.put(new AAIException("AAI_0002", "OK"), templateVars);
-
-            response = Response
-                .status(Status.OK).entity(ErrorLogHelper
-                    .getRESTAPIInfoResponse(headers.getAcceptableMediaTypes(), exceptionList))
-                .build();
-
-        } catch (Exception e) {
-            ex = new AAIException("AAI_4000", e);
-            ArrayList<String> templateVars = new ArrayList<>();
-            templateVars.add(Action.GET.name());
-            templateVars.add(fromAppId + " " + transId);
-
-            response = Response
-                .status(Status.INTERNAL_SERVER_ERROR).entity(ErrorLogHelper
-                    .getRESTAPIErrorResponse(headers.getAcceptableMediaTypes(), ex, templateVars))
-                .build();
-
-        } finally {
-            if (ex != null) {
-                ErrorLogHelper.logException(ex);
-            }
-
-        }
-
-        return response;
-    }
-
+	protected static String authPolicyFunctionName = "util";
+
+	public static final String ECHO_PATH = "/echo";
+
+	private AaiGraphChecker aaiGraphChecker;
+
+	public EchoResponse(AaiGraphChecker aaiGraphChecker) {
+		this.aaiGraphChecker = aaiGraphChecker;
+	}
+
+	/**
+	 * Simple health-check API that echos back the X-FromAppId and X-TransactionId
+	 * to clients.
+	 * If there is a query string, the healthcheck will also check for database connectivity.
+	 *
+	 * @param headers  the headers
+	 * @param req      the request
+	 * @param myAction if exists will cause database connectivity check
+	 * @return the response
+	 */
+	@GET
+	@Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON })
+	@Path(ECHO_PATH)
+	public Response echoResult(@Context HttpHeaders headers, @Context HttpServletRequest req,
+			@QueryParam("action") String myAction) {
+
+		String fromAppId;
+		String transId;
+		ArrayList<String> templateVars = new ArrayList<>();
+
+		try {
+			fromAppId = getFromAppId(headers);
+			transId = getTransId(headers);
+		} catch (AAIException aaiException) {
+			templateVars.add("PUT uebProvider");
+			templateVars.add("addTopic");
+			ErrorLogHelper.logException(aaiException);
+			return generateFailureResponse(headers, templateVars, aaiException);
+		}
+
+		templateVars.add(fromAppId);
+		templateVars.add(transId);
+		if (myAction != null) {
+			try {
+				if (!aaiGraphChecker.isAaiGraphDbAvailable()) {
+					throw new AAIException("AAI_5105", "Error establishing a database connection");
+				}
+				return generateSuccessResponse(headers, templateVars);
+			} catch (AAIException aaiException) {
+				ErrorLogHelper.logException(aaiException);
+				return generateFailureResponse(headers, templateVars, aaiException);
+			} catch (Exception e) {
+				AAIException aaiException = new AAIException("AAI_4000", e);
+				ErrorLogHelper.logException(aaiException);
+				return generateFailureResponse(headers, templateVars, aaiException);
+			}
+		}
+		return generateSuccessResponse(headers, templateVars);
+	}
+
+	private Response generateSuccessResponse(HttpHeaders headers, ArrayList<String> templateVariables) {
+		HashMap<AAIException, ArrayList<String>> exceptionList = new HashMap<>();
+		exceptionList.put(new AAIException("AAI_0002", "OK"), templateVariables);
+		try {
+			return Response.status(Status.OK)
+					.entity(
+							ErrorLogHelper.getRESTAPIInfoResponse(headers.getAcceptableMediaTypes(), exceptionList))
+					.build();
+		} catch (Exception e) {
+			AAIException aaiException = new AAIException("AAI_4000", e);
+			ErrorLogHelper.logException(aaiException);
+			return generateFailureResponse(headers, templateVariables, aaiException);
+		}
+	}
+
+	private Response generateFailureResponse(HttpHeaders headers, ArrayList<String> templateVariables,
+			AAIException aaiException) {
+		return Response.status(aaiException.getErrorObject().getHTTPResponseCode())
+				.entity(
+						ErrorLogHelper.getRESTAPIErrorResponseWithLogging(
+								headers.getAcceptableMediaTypes(), aaiException, templateVariables))
+				.build();
+	}
 }