[ONOS-7683] Add missing toString methods for telemetry configs

Change-Id: Iff17acf7b5698669ae8f753bce5a402bad06fd5c
diff --git a/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/config/DefaultRestTelemetryConfig.java b/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/config/DefaultRestTelemetryConfig.java
index 29e9a2a..df9d6ce 100644
--- a/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/config/DefaultRestTelemetryConfig.java
+++ b/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/config/DefaultRestTelemetryConfig.java
@@ -23,6 +23,7 @@
 import java.util.Map;
 import java.util.Objects;
 
+import static com.google.common.base.MoreObjects.toStringHelper;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
@@ -116,6 +117,19 @@
     }
 
     @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("address", address)
+                .add("port", port)
+                .add("endpoint", endpoint)
+                .add("method", method)
+                .add("requestMediaType", requestMediaType)
+                .add("responseMediaType", responseMediaType)
+                .add("configMap", configMap)
+                .toString();
+    }
+
+    @Override
     public TelemetryConfig.Builder createBuilder() {
         return new DefaultBuilder();
     }