Add a new CachedLocalSpawnRunner to implement remote caching + local …

…exec

The new class wraps an existing SpawnRunner and adds remote caching. Ideally,
the wrapped runner should be local and sandboxed, but this is not currently
enforced. The new class is not hooked up to anything yet.

The added test indicates that the RemoteActionCache interface is still more
complex than necessary - in particular, we should merge downloadAllResults and
downloadBlobs (for stdout/stderr) into a single method, and also change the
upload to a single combined method in a similar way instead of two calls. Doing
so allows the RemoteActionCache implementation more leeway in how it wants to
implement these, potentially improving parallelism and performance.

One step towards #1413.

PiperOrigin-RevId: 152245644

src/main/java/com/google/devtools/build/lib/remote/CachedLocalSpawnRunner.java

@@ -0,0 +1,187 @@
+// Copyright 2017 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.remote;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.actions.ActionInput;
+import com.google.devtools.build.lib.actions.ExecException;
+import com.google.devtools.build.lib.actions.Spawn;
+import com.google.devtools.build.lib.actions.UserExecException;
+import com.google.devtools.build.lib.exec.SpawnResult;
+import com.google.devtools.build.lib.exec.SpawnRunner;
+import com.google.devtools.build.lib.remote.ContentDigests.ActionKey;
+import com.google.devtools.build.lib.remote.RemoteProtocol.Action;
+import com.google.devtools.build.lib.remote.RemoteProtocol.ActionResult;
+import com.google.devtools.build.lib.remote.RemoteProtocol.Command;
+import com.google.devtools.build.lib.remote.RemoteProtocol.ContentDigest;
+import com.google.devtools.build.lib.remote.RemoteProtocol.Platform;
+import com.google.devtools.build.lib.remote.TreeNodeRepository.TreeNode;
+import com.google.devtools.build.lib.util.io.FileOutErr;
+import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.PathFragment;
+import com.google.protobuf.TextFormat;
+import com.google.protobuf.TextFormat.ParseException;
+import io.grpc.StatusRuntimeException;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.SortedMap;
+import java.util.TreeSet;
+
+/**
+ * A {@link SpawnRunner} implementation that adds a remote cache on top of an underlying local
+ * {@link SpawnRunner} implementation.
+ */
+final class CachedLocalSpawnRunner implements SpawnRunner {
+ private final Path execRoot;
+ private final RemoteOptions options;
+ // TODO(olaola): This will be set on a per-action basis instead.
+ private final Platform platform;
+
+ private final RemoteActionCache actionCache;
+ private final SpawnRunner delegate;
+
+ CachedLocalSpawnRunner(
+ Path execRoot,
+ RemoteOptions options,
+ RemoteActionCache actionCache,
+ SpawnRunner delegate) {
+ this.execRoot = execRoot;
+ this.options = options;
+ if (options.experimentalRemotePlatformOverride != null) {
+ Platform.Builder platformBuilder = Platform.newBuilder();
+ try {
+ TextFormat.getParser().merge(options.experimentalRemotePlatformOverride, platformBuilder);
+ } catch (ParseException e) {
+ throw new RuntimeException("Failed to parse --experimental_remote_platform_override", e);
+ }
+ platform = platformBuilder.build();
+ } else {
+ platform = null;
+ }
+ this.actionCache = actionCache;
+ this.delegate = delegate;
+ }
+
+ @Override
+ public SpawnResult exec(
+ Spawn spawn,
+ SpawnExecutionPolicy policy)
+ throws InterruptedException, IOException, ExecException {
+ ActionKey actionKey = null;
+ String mnemonic = spawn.getMnemonic();
+
+ try {
+ // Temporary hack: the TreeNodeRepository should be created and maintained upstream!
+ TreeNodeRepository repository =
+ new TreeNodeRepository(execRoot, policy.getActionInputFileCache());
+ SortedMap<PathFragment, ActionInput> inputMap = policy.getInputMapping();
+ TreeNode inputRoot = repository.buildFromActionInputs(inputMap);
+ repository.computeMerkleDigests(inputRoot);
+ Command command = buildCommand(spawn.getArguments(), spawn.getEnvironment());
+ Action action =
+ buildAction(
+ spawn.getOutputFiles(),
+ ContentDigests.computeDigest(command),
+ repository.getMerkleDigest(inputRoot));
+
+ // Look up action cache, and reuse the action output if it is found.
+ actionKey = ContentDigests.computeActionKey(action);
+ ActionResult result =
+ this.options.remoteAcceptCached ? actionCache.getCachedActionResult(actionKey) : null;
+ if (result != null) {
+ // We don't cache failed actions, so we know the outputs exist.
+ // For now, download all outputs locally; in the future, we can reuse the digests to
+ // just update the TreeNodeRepository and continue the build.
+ try {
+ // TODO(ulfjack): Download stdout, stderr, and the output files in a single call.
+ actionCache.downloadAllResults(result, execRoot);
+ passRemoteOutErr(result, policy.getFileOutErr());
+ return new SpawnResult.Builder()
+ .setSetupSuccess(true)
+ .setExitCode(result.getReturnCode())
+ .build();
+ } catch (CacheNotFoundException e) {
+ // TODO(ulfjack): Track down who throws this exception in what cases and double-check that
+ // ignoring the exception here is acceptable. Possible change it so that we throw in some
+ // cases - we don't want to hide failures in the remote cache from the user.
+ }
+ }
+ SpawnResult spawnResult = delegate.exec(spawn, policy);
+ if (options.remoteLocalExecUploadResults && spawnResult.setupSuccess()) {
+ writeCacheEntry(spawn, actionKey);
+ }
+ return spawnResult;
+ } catch (StatusRuntimeException e) {
+ throw new UserExecException(mnemonic + " remote work failed (" + e + ")", e);
+ }
+ }
+
+ private Action buildAction(
+ Collection<? extends ActionInput> outputs, ContentDigest command, ContentDigest inputRoot) {
+ Action.Builder action = Action.newBuilder();
+ action.setCommandDigest(command);
+ action.setInputRootDigest(inputRoot);
+ // Somewhat ugly: we rely on the stable order of outputs here for remote action caching.
+ for (ActionInput output : outputs) {
+ action.addOutputPath(output.getExecPathString());
+ }
+ if (platform != null) {
+ action.setPlatform(platform);
+ }
+ return action.build();
+ }
+
+ private static Command buildCommand(
+ List<String> arguments, ImmutableMap<String, String> environment) {
+ Command.Builder command = Command.newBuilder();
+ command.addAllArgv(arguments);
+ // Sorting the environment pairs by variable name.
+ TreeSet<String> variables = new TreeSet<>(environment.keySet());
+ for (String var : variables) {
+ command.addEnvironmentBuilder().setVariable(var).setValue(environment.get(var));
+ }
+ return command.build();
+ }
+
+ private void passRemoteOutErr(
+ ActionResult result, FileOutErr outErr)
+ throws CacheNotFoundException {
+ ImmutableList<byte[]> streams =
+ actionCache.downloadBlobs(
+ ImmutableList.of(result.getStdoutDigest(), result.getStderrDigest()));
+ outErr.printOut(new String(streams.get(0), UTF_8));
+ outErr.printErr(new String(streams.get(1), UTF_8));
+ }
+
+ private void writeCacheEntry(Spawn spawn, ActionKey actionKey)
+ throws IOException, InterruptedException {
+ ArrayList<Path> outputFiles = new ArrayList<>();
+ for (ActionInput output : spawn.getOutputFiles()) {
+ Path outputPath = execRoot.getRelative(output.getExecPathString());
+ // TODO(ulfjack): Store the actual list of output files in SpawnResult and use that instead
+ // of statting the files here again.
+ if (outputPath.exists()) {
+ outputFiles.add(outputPath);
+ }
+ }
+ ActionResult.Builder result = ActionResult.newBuilder();
+ actionCache.uploadAllResults(execRoot, outputFiles, result);
+ actionCache.setCachedActionResult(actionKey, result.build());
+ }
+}