[GitHub] [hadoop] amahussein commented on a change in pull request #2521: HDFS-15711. Add Metrics to HttpFS Server.

[GitBox <gi...@apache.org>]

amahussein commented on a change in pull request #2521:
URL: https://github.com/apache/hadoop/pull/2521#discussion_r538905542



##########
File path: hadoop-hdfs-project/hadoop-hdfs-httpfs/src/test/java/org/apache/hadoop/fs/http/server/TestHttpFSServer.java
##########
@@ -120,6 +122,25 @@
  */
 public class TestHttpFSServer extends HFSTestCase {
 
+  /**
+   * define metric getters for unit tests.
+   */
+  private static Callable<Long> defaultEntryMetricGetter = () -> 0L;
+  private static Callable<Long> defaultExitMetricGetter = () -> 1L;
+  private static HashMap<String, Callable<Long>> metricsGetter =
+      new HashMap<String, Callable<Long>>() {
+        {
+          put("LISTSTATUS",
+              () -> HttpFSServerWebApp.get().getMetrics().getOpsListing());
+          put("MKDIRS",
+              () -> HttpFSServerWebApp.get().getMetrics().getOpsMkdir());
+          put("GETFILESTATUS",
+              () -> HttpFSServerWebApp.get().getMetrics().getOpsStat());
+        }
+      };
+

Review comment:
       I found that the best way to check the metrics is to inject code in `getStatus`. This reduced the diff significantly. getStatus() accepts the cmd as a string, so adding if-then-else for each cmd will be more difficult to maintain. Finally, it is easier to add a command to the metricsGetter to extend the set of tests.
   Also, the default callable saves NPE in case the command is not mapped to a metricGetter.

##########
File path: hadoop-hdfs-project/hadoop-hdfs-httpfs/src/test/java/org/apache/hadoop/fs/http/server/TestHttpFSServer.java
##########
@@ -542,8 +572,12 @@ private void createDirWithHttp(String dirname, String perms,
     conn.setRequestMethod("PUT");
     conn.connect();
     Assert.assertEquals(HttpURLConnection.HTTP_OK, conn.getResponseCode());
+    Assert.assertEquals(1 + oldOpsMkdir,
+        HttpFSServerWebApp.get().getMetrics().getOpsMkdir());
   }
 
+
+

Review comment:
       done




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