Added logging

To enable it in component add following in properties:
logging.level.eu.h2020.symbiote.security.communication=DEBUG

src/main/java/eu/h2020/symbiote/security/communication/AAMClient.java

@@ -7,6 +7,7 @@
 import eu.h2020.symbiote.security.commons.exceptions.custom.*;
 import eu.h2020.symbiote.security.communication.interfaces.IFeignAAMClient;
 import eu.h2020.symbiote.security.communication.payloads.*;
+import eu.h2020.symbiote.security.handler.SecurityHandler;
 import feign.Feign;
 import feign.FeignException;
 import feign.Logger;
@@ -17,12 +18,16 @@
 
 import java.util.Optional;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 /**
  * Crude RMI-like client's implementation to the AAM module that communicates with it over REST.
  *
  * @author Dariusz Krajewski (PSNC)
  */
 public class AAMClient implements IAAMClient {
+    private static final Log logger = LogFactory.getLog(AAMClient.class);
 
     private static final String AAM_COMMS_ERROR_MESSAGE = "Failed to communicate with the AAM: ";
     private String serverAddress;
@@ -32,7 +37,7 @@ public class AAMClient implements IAAMClient {
      * @param serverAddress of the AAM server the client wants to interact with.
      */
     public AAMClient(String serverAddress) {
-    		this(serverAddress, new Logger.NoOpLogger());
+    		this(serverAddress, new ApacheCommonsLogger4Feign(logger));
     }
 
     /**

src/main/java/eu/h2020/symbiote/security/communication/ApacheCommonsLogger4Feign.java

@@ -0,0 +1,39 @@
+package eu.h2020.symbiote.security.communication;
+
+import java.io.IOException;
+
+import org.apache.commons.logging.Log;
+
+import feign.Request;
+import feign.Response;
+
+public class ApacheCommonsLogger4Feign extends feign.Logger {
+    private Log logger;
+
+    public ApacheCommonsLogger4Feign(Log logger) {
+        this.logger = logger;
+    }
+
+    @Override
+    protected void logRequest(String configKey, Level logLevel, Request request) {
+      if (logger.isDebugEnabled()) {
+        super.logRequest(configKey, logLevel, request);
+      }
+    }
+
+    @Override
+    protected Response logAndRebufferResponse(String configKey, Level logLevel, Response response,
+                                              long elapsedTime) throws IOException {
+      if (logger.isDebugEnabled()) {
+        return super.logAndRebufferResponse(configKey, logLevel, response, elapsedTime);
+      }
+      return response;
+    }
+
+    @Override
+    protected void log(String configKey, String format, Object... args) {
+      if (logger.isDebugEnabled()) {
+        logger.debug(String.format(methodTag(configKey) + format, args));
+      }
+    }
+}