Merge pull request #77 from EMResearch/reservations-api-busy-waiting

busy waiting for mongoDB

Author: arcuri82

jdk_11_gradle/em/embedded/rest/reservations-api/src/main/java/em/embedded/reservationsapi/EmbeddedEvoMasterController.java

@@ -96,9 +96,38 @@ public String startSut() {
                         "--app.jwt.secret=abcdef012345678901234567890123456789abcdef012345678901234567890123456789"
                 });
 
+        try {
+            Thread.sleep(3_000);
+        } catch (InterruptedException e) {
+            // do nothing
+        }
+
+        while (!isMongoClientReady()) {
+            try {
+                Thread.sleep(1_000);
+            } catch (InterruptedException e) {
+                // do nothing
+            }
+        }
+
         return "http://localhost:" + getSutPort();
     }
 
+    /**
+     * Checks if the mongo database is ready to receive commands using a ping command
+     * @return
+     */
+    private boolean isMongoClientReady() {
+        try {
+            MongoDatabase db = mongoClient.getDatabase(MONGODB_DATABASE_NAME);
+            Document pingResult = db.runCommand(new Document("ping", 1));
+            return pingResult.getDouble("ok") == 1.0;
+        } catch (Exception ex) {
+            // Connection error
+            return false;
+        }
+    }
+
     protected int getSutPort() {
         return (Integer) ((Map) ctx.getEnvironment()
                 .getPropertySources().get("server.ports").getSource())

jdk_11_gradle/em/external/rest/reservations-api/src/main/java/em/external/reservationsapi/ExternalEvoMasterController.java

@@ -153,6 +153,34 @@ public void preStart() {
 
     @Override
     public void postStart() {
+        try {
+            Thread.sleep(3_000);
+        } catch (InterruptedException e) {
+            // do nothing
+        }
+
+        while (!isMongoClientReady()) {
+            try {
+                Thread.sleep(1_000);
+            } catch (InterruptedException e) {
+                // do nothing
+            }
+        }
+    }
+
+    /**
+     * Checks if the mongo database is ready to receive commands using a ping command
+     * @return
+     */
+    private boolean isMongoClientReady() {
+        try {
+            MongoDatabase db = mongoClient.getDatabase(MONGODB_DATABASE_NAME);
+            Document pingResult = db.runCommand(new Document("ping", 1));
+            return pingResult.getDouble("ok") == 1.0;
+        } catch (Exception ex) {
+            // Connection error
+            return false;
+        }
     }
 
     @Override
@@ -270,4 +298,6 @@ public List<DbSpecification> getDbSpecifications() {
     public Object getMongoConnection() {
         return mongoClient;
     }
+
+
 }