Handle the case the info response does not contains endpoints / empty

Author: amarziali

communication/src/main/java/datadog/communication/ddagent/DDAgentFeaturesDiscovery.java

@@ -231,9 +231,14 @@ private void processInfoResponseHeaders(Response response) {
   private boolean processInfoResponse(State newState, String response) {
     try {
       Map<String, Object> map = RESPONSE_ADAPTER.fromJson(response);
+      final Object endpointObj = map.get("endpoints");
+      if (endpointObj == null) {
+        log.debug("Bad response received from the agent. Ignoring it.");
+        return false;
+      }
       discoverStatsDPort(map);
       newState.version = (String) map.get("version");
-      Set<String> endpoints = new HashSet<>((List<String>) map.get("endpoints"));
+      Set<String> endpoints = new HashSet<>((List<String>) endpointObj);
 
       String foundMetricsEndpoint = null;
       if (metricsEnabled) {

communication/src/test/groovy/datadog/communication/ddagent/DDAgentFeaturesDiscoveryTest.groovy

@@ -187,6 +187,28 @@ class DDAgentFeaturesDiscoveryTest extends DDSpecification {
     0 * _
   }
 
+  def "test fallback when /info empty"() {
+    setup:
+    OkHttpClient client = Mock(OkHttpClient)
+    DDAgentFeaturesDiscovery features = new DDAgentFeaturesDiscovery(client, monitoring, agentUrl, false, true)
+
+    when: "/info is empty"
+    features.discover()
+
+    then:
+    1 * client.newCall({ Request request -> request.url().toString() == "http://localhost:8125/info" }) >> { Request request -> infoResponse(request, "{}") }
+    0 * client.newCall({ Request request -> request.url().toString() == "http://localhost:8125/v0.6/stats" }) >> { Request request -> clientError(request) }
+    0 * client.newCall({ Request request -> request.url().toString() == "http://localhost:8125/v0.5/traces" }) >> { Request request -> success(request) }
+    1 * client.newCall({ Request request -> request.url().toString() == "http://localhost:8125/v0.4/traces" }) >> { Request request -> success(request) }
+    0 * client.newCall({ Request request -> request.url().toString() == "http://localhost:8125/v0.3/traces" }) >> { Request request -> success(request) }
+    features.getMetricsEndpoint() == null
+    !features.supportsMetrics()
+    features.getTraceEndpoint() == V04_ENDPOINT
+    !features.supportsLongRunning()
+    features.state() == PROBE_STATE
+    0 * _
+  }
+
   def "test fallback when /info not found"() {
     setup:
     OkHttpClient client = Mock(OkHttpClient)