[FIXED JENKINS-33817] Option to save backup copies of computation log.

Pass -Dcom.cloudbees.hudson.plugins.folder.computed.FolderComputation.BACKUP_LOG_COUNT=5 to save computation.log.1–computation.log.5 as backups.
jenkinsci · Mar 29, 2016 · 355600a · 355600a
1 parent b8a4fd6
commit 355600a
Showing 1 changed file with 14 additions and 1 deletion.
diff --git a/src/main/java/com/cloudbees/hudson/plugins/folder/computed/FolderComputation.java b/src/main/java/com/cloudbees/hudson/plugins/folder/computed/FolderComputation.java
@@ -57,6 +57,7 @@
 
 import hudson.util.AlternativeUiTextProvider;
 import hudson.util.AlternativeUiTextProvider.Message;
+import hudson.util.io.ReopenableRotatingFileOutputStream;
 import org.apache.commons.io.Charsets;
 import org.apache.commons.jelly.XMLOutput;
 
@@ -68,6 +69,10 @@ public class FolderComputation<I extends TopLevelItem> extends Actionable implem
 
     private static final Logger LOGGER = Logger.getLogger(FolderComputation.class.getName());
 
+    /** If defined, a number of backup log files to keep. */
+    @SuppressWarnings("FieldMayBeFinal") // let this be set dynamically by system Groovy script
+    private static @CheckForNull Integer BACKUP_LOG_COUNT = Integer.getInteger(FolderComputation.class.getName() + ".BACKUP_LOG_COUNT");
+
     /** The associated folder. */
     private transient final @Nonnull ComputedFolder<I> folder;
 
@@ -95,7 +100,15 @@ protected FolderComputation(@Nonnull ComputedFolder<I> folder, @CheckForNull Fol
     public void run() {
         StreamBuildListener listener;
         try {
-            listener = new StreamBuildListener(new FileOutputStream(getLogFile()), Charsets.UTF_8);
+            File logFile = getLogFile();
+            OutputStream os;
+            if (BACKUP_LOG_COUNT != null) {
+                os = new ReopenableRotatingFileOutputStream(logFile, BACKUP_LOG_COUNT);
+                ((ReopenableRotatingFileOutputStream) os).rewind();
+            } else {
+                os = new FileOutputStream(logFile);
+            }
+            listener = new StreamBuildListener(os, Charsets.UTF_8);
         } catch (IOException x) {
             LOGGER.log(Level.WARNING, null, x);
             result = Result.FAILURE;