Only fork jps when required (reduces overhead as well as risk of port collisions)

Author: mcculls

dd-java-agent/agent-crashtracking/src/main/java/com/datadog/crashtracking/OOMENotifierScriptInitializer.java

@@ -116,7 +116,7 @@ private static boolean copyOOMEscript(Path scriptPath) {
   private static class ScriptCleanupVisitor implements FileVisitor<Path> {
     private static final Pattern PID_PATTERN = Pattern.compile(".*?" + PID_PREFIX + "(\\d+)");
 
-    private final Set<String> pidSet = PidHelper.getJavaPids();
+    private Set<String> pidSet;
 
     static void run(Path dir) {
       try {
@@ -145,9 +145,14 @@ public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IO
       Matcher matcher = PID_PATTERN.matcher(fileName);
       if (matcher.find()) {
         String pid = matcher.group(1);
-        if (pid != null && !pid.equals(PidHelper.getPid()) && !this.pidSet.contains(pid)) {
-          LOG.debug("Cleaning process specific file {}", file);
-          Files.delete(file);
+        if (pid != null && !pid.equals(PidHelper.getPid())) {
+          if (this.pidSet == null) {
+            this.pidSet = PidHelper.getJavaPids(); // only fork jps when required
+          }
+          if (!this.pidSet.contains(pid)) {
+            LOG.debug("Cleaning process specific file {}", file);
+            Files.delete(file);
+          }
         }
       }
       return CONTINUE;

dd-java-agent/agent-profiling/profiling-controller/src/main/java/com/datadog/profiling/controller/TempLocationManager.java

@@ -73,7 +73,7 @@ default void onCleanupStart(boolean selfCleanup, long timeout, TimeUnit unit) {}
   private final class CleanupVisitor implements FileVisitor<Path> {
     private boolean shouldClean;
 
-    private final Set<String> pidSet = PidHelper.getJavaPids();
+    private Set<String> pidSet;
 
     private final boolean cleanSelf;
     private final Instant cutoff;
@@ -120,7 +120,14 @@ public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
       // the JFR repository directories are under <basedir>/pid_<pid>
       String pid = fileName.startsWith(TEMPDIR_PREFIX) ? fileName.substring(4) : null;
       boolean isSelfPid = pid != null && pid.equals(PidHelper.getPid());
-      shouldClean |= cleanSelf ? isSelfPid : !isSelfPid && !pidSet.contains(pid);
+      if (cleanSelf) {
+        shouldClean |= isSelfPid;
+      } else {
+        if (pidSet == null) {
+          pidSet = PidHelper.getJavaPids(); // only fork jps when required
+        }
+        shouldClean |= !isSelfPid && !pidSet.contains(pid);
+      }
       if (shouldClean) {
         log.debug("Cleaning temporary location {}", dir);
       }