HBASE-22225 Profiler tab on Master/RS UI not working w/o comprehensiv…

…e message
busbey · Apr 29, 2019 · 4b84ab3 · 4b84ab3
1 parent 729072e
commit 4b84ab3
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Showing 2 changed files with 26 additions and 2 deletions.
diff --git a/hbase-http/src/main/java/org/apache/hadoop/hbase/http/HttpServer.java b/hbase-http/src/main/java/org/apache/hadoop/hbase/http/HttpServer.java
@@ -733,6 +733,7 @@ protected void addDefaultServlets(ContextHandlerCollection contexts) throws IOEx
       genCtx.setResourceBase(tmpDir.toAbsolutePath().toString());
       genCtx.setDisplayName("prof-output");
     } else {
+      addServlet("prof", "/prof", ProfileServlet.DisabledServlet.class);
       LOG.info("ASYNC_PROFILER_HOME environment variable and async.profiler.home system property " +
         "not specified. Disabling /prof endpoint.");
     }

diff --git a/hbase-http/src/main/java/org/apache/hadoop/hbase/http/ProfileServlet.java b/hbase-http/src/main/java/org/apache/hadoop/hbase/http/ProfileServlet.java
@@ -85,6 +85,7 @@
  */
 @InterfaceAudience.Private
 public class ProfileServlet extends HttpServlet {
+
   private static final long serialVersionUID = 1L;
   private static final Logger LOG = LoggerFactory.getLogger(ProfileServlet.class);
 
@@ -176,7 +177,10 @@ protected void doGet(final HttpServletRequest req, final HttpServletResponse res
     if (asyncProfilerHome == null || asyncProfilerHome.trim().isEmpty()) {
       resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
       setResponseHeader(resp);
-      resp.getWriter().write("ASYNC_PROFILER_HOME env is not set.");
+      resp.getWriter().write("ASYNC_PROFILER_HOME env is not set.\n\n" +
+        "Please ensure the prerequsites for the Profiler Servlet have been installed and the\n" +
+        "environment is properly configured. For more information please see\n" +
+        "http://hbase.apache.org/book.html#profiler\n");
       return;
     }
 
@@ -357,7 +361,7 @@ private Output getOutput(final HttpServletRequest req) {
     return Output.SVG;
   }
 
-  private void setResponseHeader(final HttpServletResponse response) {
+  private static void setResponseHeader(final HttpServletResponse response) {
     response.setHeader(ACCESS_CONTROL_ALLOW_METHODS, ALLOWED_METHODS);
     response.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN, "*");
     response.setContentType(CONTENT_TYPE_TEXT);
@@ -372,4 +376,23 @@ static String getAsyncProfilerHome() {
 
     return asyncProfilerHome;
   }
+
+  public static class DisabledServlet extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
+        throws IOException {
+      resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+      setResponseHeader(resp);
+      resp.getWriter().write("The profiler servlet was disabled at startup.\n\n" +
+        "Please ensure the prerequsites for the Profiler Servlet have been installed and the\n" +
+        "environment is properly configured. For more information please see\n" +
+        "http://hbase.apache.org/book.html#profiler\n");
+      return;
+    }
+
+  }
+
 }