[JENKINS-22791] Added heap histogram generation component

jenkinsci · Oct 6, 2017 · 6e0769a · 6e0769a
1 parent b33c145
commit 6e0769a
Showing 1 changed file with 104 additions and 0 deletions.
diff --git a/src/main/java/com/cloudbees/jenkins/support/impl/HeapHisto.java b/src/main/java/com/cloudbees/jenkins/support/impl/HeapHisto.java
@@ -0,0 +1,104 @@
+package com.cloudbees.jenkins.support.impl;
+
+import com.cloudbees.jenkins.support.AsyncResultCache;
+import com.cloudbees.jenkins.support.api.Component;
+import com.cloudbees.jenkins.support.api.Container;
+import com.cloudbees.jenkins.support.api.Content;
+import edu.umd.cs.findbugs.annotations.NonNull;
+import hudson.Extension;
+import hudson.model.Node;
+import hudson.remoting.Callable;
+import hudson.security.Permission;
+import jenkins.model.Jenkins;
+import org.jenkinsci.remoting.RoleChecker;
+
+import javax.management.InstanceNotFoundException;
+import javax.management.MBeanException;
+import javax.management.MalformedObjectNameException;
+import javax.management.ObjectName;
+import javax.management.ReflectionException;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.lang.management.ManagementFactory;
+import java.util.Collections;
+import java.util.Set;
+import java.util.WeakHashMap;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+@Extension
+public class HeapHisto extends Component {
+    private static final int OFFSET = 3;
+    private static final int MAX = 500 + OFFSET;
+
+    private static final Logger logger = Logger.getLogger(HeapHisto.class.getName());
+    private final WeakHashMap<Node, String> heapHistoCache = new WeakHashMap<Node, String>();
+
+    @NonNull
+    @Override
+    public Set<Permission> getRequiredPermissions() {
+        return Collections.singleton(Jenkins.ADMINISTER);
+    }
+
+    @NonNull
+    @Override
+    public String getDisplayName() {
+        return "Master Heap Histogram -histo:live";
+    }
+
+    @Override
+    public void addContents(@NonNull Container result) {
+        result.add(
+            new Content("nodes/master/heap-histogram.txt") {
+                @Override
+                public void writeTo(OutputStream os) throws IOException {
+                    os.write(getLiveHistogram(Jenkins.getInstance()).getBytes("UTF-8"));
+                }
+            }
+        );
+    }
+
+    private String getLiveHistogram(Node node) throws IOException {
+        return AsyncResultCache.get(node,
+                heapHistoCache,
+                new GetLiveHeapHistogram(),
+                "heap histogram",
+                "N/A: No connection to node, or no cache.");
+    }
+
+    private static final class GetLiveHeapHistogram implements Callable<String, RuntimeException> {
+        public String call() {
+            final String raw = getRawLiveHistogram();
+            final String[] lines = raw.split("\n");
+            final int limit = MAX <= lines.length ? MAX : lines.length;
+
+            final StringBuilder bos = new StringBuilder();
+
+            bos.append("Master Heap Histogram -histo:live");
+            for (int i=1; i<limit; i++) {
+                bos.append(lines[i]).append('\n');
+            }
+
+            return bos.toString();
+        }
+
+        /** {@inheritDoc} */
+        @Override
+        public void checkRoles(RoleChecker checker) throws SecurityException {
+            // TODO: do we have to verify some role?
+        }
+
+        private String getRawLiveHistogram() {
+            String result;
+            try {
+                ObjectName objName = new ObjectName("com.sun.management:type=DiagnosticCommand");;
+                result = (String) ManagementFactory.getPlatformMBeanServer().invoke(objName, "gcClassHistogram", new Object[] {null}, new String[]{String[].class.getName()});
+            }
+            catch (InstanceNotFoundException | ReflectionException | MBeanException | MalformedObjectNameException e) {
+                logger.log(Level.WARNING,"Could not record heap live histogram.", e);
+                result = "NA";
+            }
+            return result;
+        }
+    }
+}