workers: When a WorkerFactory is instantiated, first remove old worker logs that belong to a prior running Bazel server.

--
MOS_MIGRATED_REVID=123092141

2 files changed, 38 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/worker/WorkerModule.java b/src/main/java/com/google/devtools/build/lib/worker/WorkerModule.java
index e16bd383c2..ef429461a3 100644
--- a/src/main/java/com/google/devtools/build/lib/worker/WorkerModule.java
+++ b/src/main/java/com/google/devtools/build/lib/worker/WorkerModule.java
@@ -59,7 +59,16 @@ public class WorkerModule extends BlazeModule {
     if (workerFactory == null) {
       Path logDir = env.getOutputBase().getRelative("worker-logs");
       try {
-        logDir.createDirectory();
+        if (!logDir.createDirectory()) {
+          // Clean out old log files.
+          for (Path logFile : logDir.getDirectoryEntries()) {
+            try {
+              logFile.delete();
+            } catch (IOException e) {
+              env.getReporter().handle(Event.error("Could not delete old worker log: " + logFile));
+            }
+          }
+        }
       } catch (IOException e) {
         env
             .getReporter()
diff --git a/src/test/shell/bazel/bazel_worker_test.sh b/src/test/shell/bazel/bazel_worker_test.sh
index 38f768d3e9..36ff8dfead 100755
--- a/src/test/shell/bazel/bazel_worker_test.sh
+++ b/src/test/shell/bazel/bazel_worker_test.sh
@@ -394,4 +394,32 @@ EOF
   expect_log "Build completed, shutting down worker pool..."
 }
 
+function test_logs_are_deleted_on_server_restart() {
+  prepare_example_worker
+  cat >>BUILD <<'EOF'
+[work(
+  name = "hello_world_%s" % idx,
+  worker = ":worker",
+  args = ["--write_uuid", "--write_counter"],
+) for idx in range(10)]
+EOF
+
+  bazel build -s --worker_verbose --strategy=Work=worker --worker_max_instances=1 --worker_quit_after_build :hello_world_1 &> $TEST_log \
+    || fail "build failed"
+
+  expect_log "Created new Work worker (id [0-9]\+)"
+
+  worker_log=$(egrep -o -- 'logging to .*/worker-logs/.*' "$TEST_log" | sed 's/^logging to //')
+
+  [ -e "$worker_log" ] \
+    || fail "Worker log was not found"
+
+  # Running a build after a server shutdown should trigger the removal of old worker log files.
+  bazel shutdown &> $TEST_log
+  bazel build &> $TEST_log
+
+  [ ! -e "$worker_log" ] \
+    || fail "Worker log was not deleted"
+}
+
 run_suite "Worker integration tests"