Merge pull request #1902 from newrelic/1750_HttpUrlConnection_memleak

Make sure we clean up the dtTracer and externalTracer when we get an …

Author: jbedell-newrelic

instrumentation/httpurlconnection/src/main/java/com/nr/agent/instrumentation/httpurlconnection/MetricState.java

@@ -11,12 +11,14 @@
 import com.newrelic.agent.bridge.TracedMethod;
 import com.newrelic.agent.bridge.Transaction;
 import com.newrelic.agent.bridge.external.URISupport;
+import com.newrelic.api.agent.GenericParameters;
 import com.newrelic.api.agent.HeaderType;
 import com.newrelic.api.agent.HttpParameters;
 import com.newrelic.api.agent.OutboundHeaders;
 
 import java.net.HttpURLConnection;
 import java.net.URI;
+import java.net.UnknownHostException;
 
 /**
  * <p>
@@ -42,6 +44,7 @@
  */
 public class MetricState {
     private static final String LIBRARY = "HttpURLConnection";
+    private static final URI UNKNOWN_HOST = URI.create("UnknownHost");
 
     // the guids for these tracers are swapped so the DT is attached to the tracer that
     // has the external
@@ -108,6 +111,24 @@ public void inboundPostamble(HttpURLConnection connection, int responseCode, Str
         }
     }
 
+    public void handleException(TracedMethod tracer, Exception e) {
+        if (externalTracer != tracer) {
+            return;
+        }
+
+        if (!externalReported && e instanceof UnknownHostException) {
+            externalTracer.reportAsExternal(GenericParameters
+                    .library(LIBRARY)
+                    .uri(UNKNOWN_HOST)
+                    .procedure("failed")
+                    .build());
+            externalReported = true;
+        }
+
+        dtTracer = null;
+        externalTracer = null;
+    }
+
     /**
      * Calls the reportAsExternal API. This results in a Span being created for the current TracedMethod/Segment and the Span
      * category being set to http which represents a Span that made an external http request. This is required for external

instrumentation/httpurlconnection/src/main/java/java/net/HttpURLConnection.java

@@ -78,10 +78,7 @@ public synchronized InputStream getInputStream() throws IOException {
             // This does a network request (if getResponseCode() wasn't called first)
             inputStream = Weaver.callOriginal();
         } catch (Exception e) {
-            // This is the default legacy behavior of the AbstractExternalComponentTracer
-            if (e instanceof UnknownHostException) {
-                method.setMetricName("External", "UnknownHost", "HttpURLConnection");
-            }
+            metricState.handleException(method, e);
             throw e;
         }
 
@@ -103,10 +100,7 @@ public int getResponseCode() throws Exception {
             // This does a network request (if getInputStream() wasn't called first)
             responseCodeValue = Weaver.callOriginal();
         } catch (Exception e) {
-            // This is the default legacy behavior of the AbstractExternalComponentTracer
-            if (e instanceof UnknownHostException) {
-                method.setMetricName("External", "UnknownHost", "HttpURLConnection");
-            }
+            metricState.handleException(method, e);
             throw e;
         }
 
@@ -123,9 +117,7 @@ public String getResponseMessage()  throws IOException {
         try {
             responseMessageValue = Weaver.callOriginal();
         } catch (Exception e) {
-            if (e instanceof UnknownHostException) {
-                method.setMetricName("External", "UnknownHost", "HttpURLConnection");
-            }
+            metricState.handleException(method, e);
             throw e;
         }
         metricState.inboundPostamble(this, responseCode, responseMessageValue, GET_RESPONSE_MSG, method);