Merge pull request #88 from batmat/gclogs

[FIX JENKINS-39607] GC logs should be collected
jenkinsci · Nov 9, 2016 · c4cea8d · c4cea8d
2 parents ab6ef42 + 41fcbfd
commit c4cea8d
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diff --git a/pom.xml b/pom.xml
@@ -104,6 +104,12 @@
       <version>1.7.8</version>
       <optional>true</optional>
     </dependency>
+      <dependency>
+          <groupId>org.mockito</groupId>
+          <artifactId>mockito-core</artifactId>
+          <version>2.2.15</version>
+          <scope>test</scope>
+      </dependency>
   </dependencies>
 
 </project>
diff --git a/src/main/java/com/cloudbees/jenkins/support/impl/GCLogs.java b/src/main/java/com/cloudbees/jenkins/support/impl/GCLogs.java
@@ -0,0 +1,166 @@
+package com.cloudbees.jenkins.support.impl;
+
+import com.cloudbees.jenkins.support.api.Component;
+import com.cloudbees.jenkins.support.api.Container;
+import com.cloudbees.jenkins.support.api.FileContent;
+import edu.umd.cs.findbugs.annotations.NonNull;
+import hudson.Extension;
+import hudson.security.Permission;
+import jenkins.model.Jenkins;
+
+import javax.annotation.CheckForNull;
+import javax.annotation.Nonnull;
+import java.io.File;
+import java.io.FilenameFilter;
+import java.lang.management.ManagementFactory;
+import java.util.Collections;
+import java.util.Set;
+import java.util.logging.Logger;
+import java.util.regex.Pattern;
+
+/**
+ * GC Logs Retriever.
+ * <p>
+ * <p>Introspects the running VM for <code>-Xloggc:blah.log</code> option and so on to propose including those if
+ * found</p>
+ * <p>
+ * NOTE: currently only tested on OpenJDK / HotSpot.
+ * </p>
+ */
+@Extension(ordinal = 90.0) // probably big too, see JenkinsLogs
+public class GCLogs extends Component {
+
+    static final String GCLOGS_JRE_SWITCH = "-Xloggc:";
+
+    static final String GCLOGS_ROTATION_SWITCH = "-XX:+UseGCLogFileRotation";
+
+    private static final String GCLOGS_BUNDLE_ROOT = "/nodes/master/logs/gc/";
+
+    private static final Logger LOGGER = Logger.getLogger(GCLogs.class.getName());
+
+    private final VmArgumentFinder vmArgumentFinder;
+
+    public GCLogs() {
+        this(new VmArgumentFinder());
+    }
+
+    /**
+     * Designed for testing use only.
+     *
+     * @param vmArgumentFinder pass the impl you want to override the default one.
+     */
+    GCLogs(VmArgumentFinder vmArgumentFinder) {
+        this.vmArgumentFinder = vmArgumentFinder;
+    }
+
+    @NonNull
+    @Override
+    public Set<Permission> getRequiredPermissions() {
+        return Collections.singleton(Jenkins.ADMINISTER);
+    }
+
+    @NonNull
+    @Override
+    public String getDisplayName() {
+        return "Garbage Collection Logs";
+    }
+
+    @Override
+    public boolean isEnabled() {
+        boolean gcLogsConfigured = getGcLogFileLocation() != null;
+        LOGGER.fine("GC logs configured: " + gcLogsConfigured);
+        return super.isEnabled() && gcLogsConfigured;
+    }
+
+    @Override
+    public void addContents(@NonNull Container result) {
+        LOGGER.fine("Trying to gather GC logs for support bundle");
+        String gcLogFileLocation = getGcLogFileLocation();
+        assert gcLogFileLocation != null; // non nullable here 'cause isEnabled() already checks it
+
+        if (isGcLogRotationConfigured()) {
+            handleRotatedLogs(gcLogFileLocation, result);
+        } else {
+            File file = new File(gcLogFileLocation);
+            if (!file.exists()) {
+                LOGGER.warning("[Support Bundle] GC Logging apparently configured, " +
+                        "but file '" + gcLogFileLocation + "' not found");
+                return;
+            }
+            result.add(new FileContent(GCLOGS_BUNDLE_ROOT + "gc.log", file));
+        }
+    }
+
+    /**
+     * Two cases:
+     * <ul>
+     * <li>The file name contains <code>%t</code> or <code>%p</code> somewhere in the middle:
+     * then we are simply going to replace those by <code>.*</code> to find associated logs and match files by regex.
+     * This will match GC logs from the current JVM execution, or possibly previous ones.</li>
+     * <li>or that feature is not used, then we simply match by "starts with"</li>
+     * </ul>
+     *
+     * @param gcLogFileLocation the specified value after <code>-Xloggc:</code>
+     * @param result            the container where to add the found logs, if any.
+     * @see https://bugs.openjdk.java.net/browse/JDK-7164841
+     */
+    private void handleRotatedLogs(@Nonnull final String gcLogFileLocation, Container result) {
+        // always add .* in the end because this is where the numbering is going to happen
+        String regex = gcLogFileLocation.replaceAll("%[pt]", ".*") + ".*";
+        final Pattern gcLogFilesPattern = Pattern.compile(regex);
+
+        File parentDirectory = new File(gcLogFileLocation).getParentFile();
+
+        if (parentDirectory == null || !parentDirectory.exists()) {
+            LOGGER.warning("[Support Bundle] " + parentDirectory + " does not exist, cannot collect gc logging files.");
+            return;
+        }
+
+        File[] gcLogs = parentDirectory.listFiles(new FilenameFilter() {
+            @Override
+            public boolean accept(File dir, String name) {
+                return gcLogFilesPattern.matcher(dir + "/" + name).matches();
+            }
+        });
+        if (gcLogs == null || gcLogs.length == 0) {
+            LOGGER.warning("No GC logging files found, although the VM argument was found. This is probably a bug.");
+            return;
+        }
+
+        LOGGER.finest("Found " + gcLogs.length + " matching files in " + parentDirectory.getAbsolutePath());
+        for (File gcLog : gcLogs) {
+            LOGGER.finest("Adding '" + gcLog.getName() + "' file");
+            result.add(new FileContent(GCLOGS_BUNDLE_ROOT + gcLog.getName(), gcLog));
+        }
+    }
+
+    @CheckForNull
+    private String getGcLogFileLocation() {
+
+        String gcLogSwitch = vmArgumentFinder.findVmArgument(GCLOGS_JRE_SWITCH);
+        if (gcLogSwitch == null) {
+            LOGGER.fine("No GC Logging switch found, cannot collect gc logging files.");
+            return null;
+        }
+        return gcLogSwitch.substring(GCLOGS_JRE_SWITCH.length());
+    }
+
+    private boolean isGcLogRotationConfigured() {
+        return vmArgumentFinder.findVmArgument(GCLOGS_ROTATION_SWITCH) != null;
+    }
+
+    /**
+     * Isolated code to make it testable
+     */
+    static class VmArgumentFinder {
+        @CheckForNull
+        public String findVmArgument(String argName) {
+            for (String argument : ManagementFactory.getRuntimeMXBean().getInputArguments()) {
+                if (argument.startsWith(argName)) {
+                    return argument;
+                }
+            }
+            return null;
+        }
+    }
+}
diff --git a/src/test/java/com/cloudbees/jenkins/support/impl/GCLogsTest.java b/src/test/java/com/cloudbees/jenkins/support/impl/GCLogsTest.java
@@ -0,0 +1,67 @@
+package com.cloudbees.jenkins.support.impl;
+
+import com.cloudbees.jenkins.support.api.Container;
+import com.cloudbees.jenkins.support.api.Content;
+import com.google.common.io.Files;
+import edu.umd.cs.findbugs.annotations.CheckForNull;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class GCLogsTest {
+
+    @Test
+    public void simpleFile() throws Exception {
+        File tmpFile = File.createTempFile("gclogs", "");
+        Files.touch(tmpFile);
+
+        GCLogs.VmArgumentFinder finder = mock(GCLogs.VmArgumentFinder.class);
+        when(finder.findVmArgument(GCLogs.GCLOGS_JRE_SWITCH)).thenReturn(GCLogs.GCLOGS_JRE_SWITCH + tmpFile.getAbsolutePath());
+
+        TestContainer container = new TestContainer();
+
+        new GCLogs(finder).addContents(container);
+
+        assertEquals(1, container.getContents().size());
+    }
+
+    @Test
+    public void rotatedFiles() throws Exception {
+        File tempDir = Files.createTempDir();
+        for (int count = 0; count < 10; count++) {
+            Files.touch(new File(tempDir, "gc5625.log" + count));
+        }
+        for (int count = 0; count < 5; count++) {
+            Files.touch(new File(tempDir, "gc3421.log" + count));
+        }
+
+        GCLogs.VmArgumentFinder finder = mock(GCLogs.VmArgumentFinder.class);
+        when(finder.findVmArgument(GCLogs.GCLOGS_JRE_SWITCH)).thenReturn(GCLogs.GCLOGS_JRE_SWITCH + new File(tempDir, "gc%p.log").getAbsolutePath());
+        when(finder.findVmArgument(GCLogs.GCLOGS_ROTATION_SWITCH)).thenReturn(GCLogs.GCLOGS_ROTATION_SWITCH);
+
+        TestContainer container = new TestContainer();
+
+        new GCLogs(finder).addContents(container);
+
+        assertEquals(15, container.getContents().size());
+    }
+
+    private static class TestContainer extends Container {
+        List<Content> contents = new ArrayList<Content>();
+
+        public List<Content> getContents() {
+            return contents;
+        }
+
+        @Override
+        public void add(@CheckForNull Content content) {
+            contents.add(content);
+        }
+    }
+}