Move pid file watcher to its own class
Declutters GrpcServerImpl, makes it easier to test in isolation, and makes the
pid more readily available for other things that may want it.
The @VisibleForTesting arrangement is slightly awkward, but I think it's worth
it to have the test coverage given the number of times I messed up this
refactoring.
PiperOrigin-RevId: 328986378
diff --git a/src/test/java/com/google/devtools/build/lib/server/PidFileWatcherTest.java b/src/test/java/com/google/devtools/build/lib/server/PidFileWatcherTest.java
new file mode 100644
index 0000000..5d43f9e
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/server/PidFileWatcherTest.java
@@ -0,0 +1,103 @@
+// Copyright 2020 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.server;
+
+import static com.google.common.truth.Truth.assertThat;
+import static java.nio.charset.StandardCharsets.US_ASCII;
+import static org.junit.Assert.assertThrows;
+
+import com.google.devtools.build.lib.vfs.FileSystem;
+import com.google.devtools.build.lib.vfs.FileSystemUtils;
+import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
+import java.io.IOException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link PidFileWatcher}. */
+@RunWith(JUnit4.class)
+public class PidFileWatcherTest {
+
+ private static final int EXPECTED_PID = 42;
+ private static final IllegalStateException THROWN_ON_HALT = new IllegalStateException("crash!");
+
+ private Path pidFile;
+ private PidFileWatcher underTest;
+
+ @Before
+ public void setUp() {
+ FileSystem fileSystem = new InMemoryFileSystem();
+ pidFile = fileSystem.getPath("/pid");
+ underTest =
+ new PidFileWatcher(
+ pidFile,
+ EXPECTED_PID,
+ () -> {
+ throw THROWN_ON_HALT;
+ });
+ }
+
+ @Test
+ public void testMissingPidFileHaltsProgram() throws IOException {
+ // Delete just in case.
+ pidFile.delete();
+
+ assertPidCheckHaltsProgram();
+ }
+
+ @Test
+ public void testEmptyPidFileCountsAsChanged() throws IOException {
+ FileSystemUtils.writeContent(pidFile, new byte[0]);
+
+ assertPidCheckHaltsProgram();
+ }
+
+ @Test
+ public void testGarbagePidFileCountsAsChanged() throws IOException {
+ FileSystemUtils.writeContent(pidFile, "junk".getBytes(US_ASCII));
+
+ assertPidCheckHaltsProgram();
+ }
+
+ @Test
+ public void testPidFileContinuesExecution() throws IOException {
+ FileSystemUtils.writeContent(pidFile, "42".getBytes(US_ASCII));
+
+ assertThat(underTest.runPidFileChecks()).isTrue();
+ }
+
+ @Test
+ public void testPidFileTrailingWhitespaceNotTolerated() throws IOException {
+ FileSystemUtils.writeContent(pidFile, "42\n".getBytes(US_ASCII));
+
+ assertPidCheckHaltsProgram();
+ }
+
+ @Test
+ public void testPidFileChangeAfterShutdownNotificationStopsWatcher() throws IOException {
+ FileSystemUtils.writeContent(pidFile, "42\n".getBytes(US_ASCII));
+
+ underTest.signalShutdown();
+ assertThat(underTest.runPidFileChecks()).isFalse();
+ }
+
+ private void assertPidCheckHaltsProgram() {
+ IllegalStateException expected =
+ assertThrows(IllegalStateException.class, underTest::runPidFileChecks);
+ assertThat(expected).isSameInstanceAs(THROWN_ON_HALT);
+ }
+}
