use request attribute to flag if filterChain throws exception.

if an exception has been thrown, assume failed request with status=500

Author: littleaj

web/src/main/java/com/microsoft/applicationinsights/web/internal/WebRequestTrackingFilter.java

@@ -73,23 +73,28 @@ public final class WebRequestTrackingFilter implements Filter {
     static {
         WebReflectionUtils.initialize();
     }
+
     // region Members
     // Visible for testing
-    final static String FILTER_NAME = "ApplicationInsightsWebFilter";
-    private final static String WEB_INF_FOLDER = "WEB-INF/";
+    static final String FILTER_NAME = "ApplicationInsightsWebFilter";
+    private static final String WEB_INF_FOLDER = "WEB-INF/";
 
     private WebModulesContainer webModulesContainer;
     private TelemetryClient telemetryClient;
     private final List<ThreadLocalCleaner> cleaners = new LinkedList<ThreadLocalCleaner>();
     private String appName;
-    private static final String AGENT_LOCATOR_INTERFACE_NAME = "com.microsoft.applicationinsights."
-        + "agent.internal.coresync.AgentNotificationsHandler";
+    private static final String AGENT_LOCATOR_INTERFACE_NAME = "com.microsoft.applicationinsights.agent.internal.coresync.AgentNotificationsHandler";
     private String filterName = FILTER_NAME;
 
     /**
      * Constant for marking already processed request
      */
-    private final String ALREADY_FILTERED = "AI_FILTER_PROCESSED";
+    private static final String ALREADY_FILTERED = "AI_FILTER_PROCESSED";
+    /**
+     * Request Attribute to flag if exception was thrown from servlet/downstream filter.
+     * Value will be the caught (and rethrown) exception/throwable.
+     */
+    public static final String APPLICATION_INSIGHTS_CAUGHT_EXCEPTION = "AI_CAUGHT_EXCEPTION";
 
     /**
      * Utility handler used to instrument request start and end
@@ -137,13 +142,13 @@ public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
                 httpRequest.setAttribute(ALREADY_FILTERED, Boolean.TRUE);
                 chain.doFilter(httpRequest, httpResponse);
             } catch (ServletException | IOException | RuntimeException e) {
+                httpRequest.setAttribute(APPLICATION_INSIGHTS_CAUGHT_EXCEPTION, e);
                 handler.handleException(e);
                 throw e;
             } finally {
                 if (httpRequest.isAsyncStarted()) {
                     AsyncContext context = httpRequest.getAsyncContext();
-                    AIHttpServletListener aiHttpServletListener =
-                            new AIHttpServletListener(handler, requestTelemetryContext, agentBinding);
+                    AIHttpServletListener aiHttpServletListener = new AIHttpServletListener(handler, requestTelemetryContext, agentBinding);
                     context.addListener(aiHttpServletListener, httpRequest, httpResponse);
                 } else {
                     handler.handleEnd(httpRequest, httpResponse, requestTelemetryContext);

web/src/main/java/com/microsoft/applicationinsights/web/internal/httputils/AIHttpServletListener.java

@@ -9,6 +9,8 @@
 import javax.servlet.AsyncListener;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
+
+import com.microsoft.applicationinsights.web.internal.WebRequestTrackingFilter;
 import org.apache.commons.lang3.Validate;
 
 /**
@@ -71,6 +73,7 @@ public void onError(AsyncEvent event) {
         } else {
             InternalLogger.INSTANCE.warn("Throwable is not instance of exception, cannot be captured: %s", throwable);
         }
+        request.setAttribute(WebRequestTrackingFilter.APPLICATION_INSIGHTS_CAUGHT_EXCEPTION, throwable);
         handler.handleEnd(request, response, context);
         if (agentBinding != null) {
             agentBinding.unbindFromRunawayChildThreads();

web/src/main/java/com/microsoft/applicationinsights/web/internal/httputils/HttpServerHandler.java

@@ -14,6 +14,8 @@
 import java.util.List;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
+
+import com.microsoft.applicationinsights.web.internal.WebRequestTrackingFilter;
 import org.apache.commons.lang3.Validate;
 import org.apache.commons.lang3.exception.ExceptionUtils;
 
@@ -112,6 +114,11 @@ public void handleEnd(ServletRequest request, ServletResponse response,
         int resultCode = extractor.getStatusCode(response);
         requestTelemetry.setSuccess(resultCode < 400);
         requestTelemetry.setResponseCode(Integer.toString(resultCode));
+        if (request.getAttribute(WebRequestTrackingFilter.APPLICATION_INSIGHTS_CAUGHT_EXCEPTION) != null) {
+            requestTelemetry.setSuccess(false);
+            requestTelemetry.setResponseCode("500");
+        }
+
         if (ThreadContext.getRequestTelemetryContext() == null) {
             // e.g. when called from AIHttpServletListener
             ThreadContext.setRequestTelemetryContext(context);