blob: 9edc6702aa1ad1b91ef71ae8047ee8ddc0bc5e9a [file] [log] [blame]
// Copyright 2016 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 org.junit.Assert.assertThrows;
import com.google.devtools.build.lib.clock.JavaClock;
import com.google.devtools.build.lib.runtime.BlazeCommandResult;
import com.google.devtools.build.lib.runtime.CommandDispatcher;
import com.google.devtools.build.lib.runtime.CommandDispatcher.LockingMode;
import com.google.devtools.build.lib.runtime.proto.InvocationPolicyOuterClass.InvocationPolicy;
import com.google.devtools.build.lib.server.CommandProtos.CancelRequest;
import com.google.devtools.build.lib.server.CommandProtos.CancelResponse;
import com.google.devtools.build.lib.server.CommandProtos.RunRequest;
import com.google.devtools.build.lib.server.CommandProtos.RunResponse;
import com.google.devtools.build.lib.server.CommandServerGrpc.CommandServerStub;
import com.google.devtools.build.lib.server.FailureDetails.Command;
import com.google.devtools.build.lib.server.FailureDetails.FailureDetail;
import com.google.devtools.build.lib.server.FailureDetails.GrpcServer;
import com.google.devtools.build.lib.server.FailureDetails.Interrupted;
import com.google.devtools.build.lib.server.FailureDetails.Interrupted.Code;
import com.google.devtools.build.lib.server.GrpcServerImpl.BlockingStreamObserver;
import com.google.devtools.build.lib.testutil.Suite;
import com.google.devtools.build.lib.testutil.TestSpec;
import com.google.devtools.build.lib.util.Pair;
import com.google.devtools.build.lib.util.io.OutErr;
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 com.google.protobuf.ByteString;
import io.grpc.ManagedChannel;
import io.grpc.Server;
import io.grpc.inprocess.InProcessChannelBuilder;
import io.grpc.inprocess.InProcessServerBuilder;
import io.grpc.stub.ServerCallStreamObserver;
import io.grpc.stub.StreamObserver;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.stream.Collectors;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
/** Unit tests for the gRPC server. */
@TestSpec(size = Suite.SMALL_TESTS)
@RunWith(JUnit4.class)
public class GrpcServerTest {
private static final String REQUEST_COOKIE = "request-cookie";
private final FileSystem fileSystem = new InMemoryFileSystem();
private Path serverDirectory;
private GrpcServerImpl serverImpl;
private Server server;
private ManagedChannel channel;
private void createServer(CommandDispatcher dispatcher) throws Exception {
serverDirectory = fileSystem.getPath("/bazel_server_directory");
serverDirectory.createDirectoryAndParents();
FileSystemUtils.writeContentAsLatin1(serverDirectory.getChild("server.pid.txt"), "12345");
serverImpl =
new GrpcServerImpl(
dispatcher,
new JavaClock(),
/* port= */ -1,
REQUEST_COOKIE,
"response-cookie",
serverDirectory,
1000,
false,
false);
String uniqueName = InProcessServerBuilder.generateName();
server =
InProcessServerBuilder.forName(uniqueName)
.directExecutor()
.addService(serverImpl)
.build()
.start();
channel = InProcessChannelBuilder.forName(uniqueName).directExecutor().build();
}
private RunRequest createRequest(String... args) {
return RunRequest.newBuilder()
.setCookie(REQUEST_COOKIE)
.setClientDescription("client-description")
.addAllArg(Arrays.stream(args).map(ByteString::copyFromUtf8).collect(Collectors.toList()))
.build();
}
@Test
public void testSendingSimpleMessage() throws Exception {
AtomicReference<List<String>> argsReceived = new AtomicReference<>();
CommandDispatcher dispatcher =
new CommandDispatcher() {
@Override
public BlazeCommandResult exec(
InvocationPolicy invocationPolicy,
List<String> args,
OutErr outErr,
LockingMode lockingMode,
String clientDescription,
long firstContactTimeMillis,
Optional<List<Pair<String, String>>> startupOptionsTaggedWithBazelRc) {
argsReceived.set(args);
return BlazeCommandResult.success();
}
};
createServer(dispatcher);
CountDownLatch done = new CountDownLatch(1);
CommandServerStub stub = CommandServerGrpc.newStub(channel);
List<RunResponse> responses = new ArrayList<>();
stub.run(createRequest("Foo"), createResponseObserver(responses, done));
done.await();
server.shutdown();
server.awaitTermination();
assertThat(argsReceived.get()).isNotNull();
assertThat(argsReceived.get()).containsExactly("Foo");
assertThat(responses).hasSize(2);
assertThat(responses.get(0).getFinished()).isFalse();
assertThat(responses.get(0).getCookie()).isNotEmpty();
assertThat(responses.get(1).getFinished()).isTrue();
assertThat(responses.get(1).getExitCode()).isEqualTo(0);
assertThat(responses.get(1).hasFailureDetail()).isFalse();
}
@Test
public void testClosingClientShouldInterrupt() throws Exception {
CountDownLatch done = new CountDownLatch(1);
CommandDispatcher dispatcher =
new CommandDispatcher() {
@Override
public BlazeCommandResult exec(
InvocationPolicy invocationPolicy,
List<String> args,
OutErr outErr,
LockingMode lockingMode,
String clientDescription,
long firstContactTimeMillis,
Optional<List<Pair<String, String>>> startupOptionsTaggedWithBazelRc) {
synchronized (this) {
assertThrows(InterruptedException.class, this::wait);
}
// The only way this can happen is if the current thread is interrupted.
done.countDown();
return BlazeCommandResult.failureDetail(
FailureDetail.newBuilder()
.setInterrupted(Interrupted.newBuilder().setCode(Code.INTERRUPTED_UNKNOWN))
.build());
}
};
createServer(dispatcher);
CommandServerStub stub = CommandServerGrpc.newStub(channel);
stub.run(
createRequest("Foo"),
new StreamObserver<RunResponse>() {
@Override
public void onNext(RunResponse value) {
server.shutdownNow();
done.countDown();
}
@Override
public void onError(Throwable t) {}
@Override
public void onCompleted() {}
});
server.awaitTermination();
done.await();
}
@Test
public void testStream() throws Exception {
CommandDispatcher dispatcher =
new CommandDispatcher() {
@Override
public BlazeCommandResult exec(
InvocationPolicy invocationPolicy,
List<String> args,
OutErr outErr,
LockingMode lockingMode,
String clientDescription,
long firstContactTimeMillis,
Optional<List<Pair<String, String>>> startupOptionsTaggedWithBazelRc) {
OutputStream out = outErr.getOutputStream();
try {
for (int i = 0; i < 10; i++) {
out.write(new byte[1024]);
}
} catch (IOException e) {
throw new IllegalStateException(e);
}
return BlazeCommandResult.success();
}
};
createServer(dispatcher);
CountDownLatch done = new CountDownLatch(1);
CommandServerStub stub = CommandServerGrpc.newStub(channel);
List<RunResponse> responses = new ArrayList<>();
stub.run(createRequest("Foo"), createResponseObserver(responses, done));
done.await();
server.shutdown();
server.awaitTermination();
assertThat(responses).hasSize(12);
assertThat(responses.get(0).getFinished()).isFalse();
assertThat(responses.get(0).getCookie()).isNotEmpty();
for (int i = 1; i < 11; i++) {
assertThat(responses.get(i).getFinished()).isFalse();
assertThat(responses.get(i).getStandardOutput().toByteArray()).isEqualTo(new byte[1024]);
}
assertThat(responses.get(11).getFinished()).isTrue();
assertThat(responses.get(11).getExitCode()).isEqualTo(0);
assertThat(responses.get(11).hasFailureDetail()).isFalse();
}
@Test
public void badCookie() throws Exception {
runBadCommandTest(
RunRequest.newBuilder().setCookie("bad-cookie").setClientDescription("client-description"),
FailureDetail.newBuilder()
.setMessage("Invalid RunRequest: bad cookie")
.setGrpcServer(GrpcServer.newBuilder().setCode(GrpcServer.Code.BAD_COOKIE))
.build());
}
@Test
public void emptyClientDescription() throws Exception {
runBadCommandTest(
RunRequest.newBuilder().setCookie(REQUEST_COOKIE).setClientDescription(""),
FailureDetail.newBuilder()
.setMessage("Invalid RunRequest: no client description")
.setGrpcServer(GrpcServer.newBuilder().setCode(GrpcServer.Code.NO_CLIENT_DESCRIPTION))
.build());
}
private void runBadCommandTest(RunRequest.Builder runRequestBuilder, FailureDetail failureDetail)
throws Exception {
createServer(GrpcServerTest::unexpectedCommandExec);
CountDownLatch done = new CountDownLatch(1);
CommandServerStub stub = CommandServerGrpc.newStub(channel);
List<RunResponse> responses = new ArrayList<>();
stub.run(
runRequestBuilder.addArg(ByteString.copyFromUtf8("Foo")).build(),
createResponseObserver(responses, done));
done.await();
server.shutdown();
server.awaitTermination();
assertThat(responses).hasSize(1);
assertThat(responses.get(0).getFinished()).isTrue();
assertThat(responses.get(0).getExitCode()).isEqualTo(36);
assertThat(responses.get(0).hasFailureDetail()).isTrue();
assertThat(responses.get(0).getFailureDetail()).isEqualTo(failureDetail);
}
@Test
public void unparseableInvocationPolicy() throws Exception {
createServer(GrpcServerTest::unexpectedCommandExec);
CountDownLatch done = new CountDownLatch(1);
CommandServerStub stub = CommandServerGrpc.newStub(channel);
List<RunResponse> responses = new ArrayList<>();
stub.run(
RunRequest.newBuilder()
.setCookie(REQUEST_COOKIE)
.setClientDescription("client-description")
.setInvocationPolicy("invalid-invocation-policy")
.addArg(ByteString.copyFromUtf8("Foo"))
.build(),
createResponseObserver(responses, done));
done.await();
server.shutdown();
server.awaitTermination();
assertThat(responses).hasSize(3);
assertThat(responses.get(2).getFinished()).isTrue();
assertThat(responses.get(2).getExitCode()).isEqualTo(2);
assertThat(responses.get(2).hasFailureDetail()).isTrue();
assertThat(responses.get(2).getFailureDetail())
.isEqualTo(
FailureDetail.newBuilder()
.setMessage(
"Invocation policy parsing failed: Malformed value of --invocation_policy: "
+ "invalid-invocation-policy")
.setCommand(
Command.newBuilder().setCode(Command.Code.INVOCATION_POLICY_PARSE_FAILURE))
.build());
}
@Test
public void testInterruptStream() throws Exception {
CountDownLatch done = new CountDownLatch(1);
CommandDispatcher dispatcher =
new CommandDispatcher() {
@Override
public BlazeCommandResult exec(
InvocationPolicy invocationPolicy,
List<String> args,
OutErr outErr,
LockingMode lockingMode,
String clientDescription,
long firstContactTimeMillis,
Optional<List<Pair<String, String>>> startupOptionsTaggedWithBazelRc) {
OutputStream out = outErr.getOutputStream();
try {
while (true) {
if (Thread.interrupted()) {
return BlazeCommandResult.failureDetail(
FailureDetail.newBuilder()
.setInterrupted(
Interrupted.newBuilder().setCode(Code.INTERRUPTED_UNKNOWN))
.build());
}
out.write(new byte[1024]);
}
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
};
createServer(dispatcher);
CommandServerStub stub = CommandServerGrpc.newStub(channel);
List<RunResponse> responses = new ArrayList<>();
stub.run(
createRequest("Foo"),
new StreamObserver<RunResponse>() {
@Override
public void onNext(RunResponse value) {
responses.add(value);
if (responses.size() == 10) {
server.shutdownNow();
}
}
@Override
public void onError(Throwable t) {
done.countDown();
}
@Override
public void onCompleted() {
done.countDown();
}
});
server.awaitTermination();
done.await();
}
@Test
public void testCancel() throws Exception {
CommandDispatcher dispatcher =
new CommandDispatcher() {
@Override
public BlazeCommandResult exec(
InvocationPolicy invocationPolicy,
List<String> args,
OutErr outErr,
LockingMode lockingMode,
String clientDescription,
long firstContactTimeMillis,
Optional<List<Pair<String, String>>> startupOptionsTaggedWithBazelRc)
throws InterruptedException {
synchronized (this) {
this.wait();
}
// Interruption expected before this is reached.
throw new IllegalStateException();
}
};
createServer(dispatcher);
AtomicReference<String> commandId = new AtomicReference<>();
CountDownLatch gotCommandId = new CountDownLatch(1);
AtomicReference<RunResponse> secondResponse = new AtomicReference<>();
CountDownLatch gotSecondResponse = new CountDownLatch(1);
CommandServerStub stub = CommandServerGrpc.newStub(channel);
stub.run(
createRequest("Foo"),
new StreamObserver<RunResponse>() {
@Override
public void onNext(RunResponse value) {
String previousCommandId = commandId.getAndSet(value.getCommandId());
if (previousCommandId == null) {
gotCommandId.countDown();
} else {
secondResponse.set(value);
gotSecondResponse.countDown();
}
}
@Override
public void onError(Throwable t) {}
@Override
public void onCompleted() {}
});
// Wait until we've got the command id.
gotCommandId.await();
CountDownLatch cancelRequestComplete = new CountDownLatch(1);
CancelRequest cancelRequest =
CancelRequest.newBuilder().setCookie(REQUEST_COOKIE).setCommandId(commandId.get()).build();
stub.cancel(
cancelRequest,
new StreamObserver<CancelResponse>() {
@Override
public void onNext(CancelResponse value) {}
@Override
public void onError(Throwable t) {}
@Override
public void onCompleted() {
cancelRequestComplete.countDown();
}
});
cancelRequestComplete.await();
gotSecondResponse.await();
server.shutdown();
server.awaitTermination();
assertThat(secondResponse.get().getFinished()).isTrue();
assertThat(secondResponse.get().getExitCode()).isEqualTo(8);
assertThat(secondResponse.get().hasFailureDetail()).isTrue();
assertThat(secondResponse.get().getFailureDetail().hasInterrupted()).isTrue();
assertThat(secondResponse.get().getFailureDetail().getInterrupted().getCode())
.isEqualTo(Code.COMMAND_DISPATCH);
}
@Test
public void testFlowControl() throws Exception {
// This test attempts to verify that FlowControl successfully blocks after some number of onNext
// calls (however long it takes to fill up gRPCs internal buffers). In order to trigger this
// behavior, we intentionally block the client after a few successful calls, then wait a bit,
// and then check that the server has stopped prematurely. Unfortunately, we cannot
// deterministically verify that the onNext call is blocking. A faulty implementation of
// FlowControl could pass this test if the sleep is too short. However, a correct implementation
// should never fail this test.
// This test could start failing if gRPCs internal buffer size is increased. If it fails after
// an upgrade of gRPC, you might want to check that.
CountDownLatch serverDone = new CountDownLatch(1);
CountDownLatch clientBlocks = new CountDownLatch(1);
CountDownLatch clientUnblocks = new CountDownLatch(1);
CountDownLatch clientDone = new CountDownLatch(1);
AtomicInteger sentCount = new AtomicInteger();
AtomicInteger receiveCount = new AtomicInteger();
CommandServerGrpc.CommandServerImplBase serverImpl =
new CommandServerGrpc.CommandServerImplBase() {
@Override
public void run(RunRequest request, StreamObserver<RunResponse> observer) {
ServerCallStreamObserver<RunResponse> serverCallStreamObserver =
(ServerCallStreamObserver<RunResponse>) observer;
BlockingStreamObserver<RunResponse> blockingStreamObserver =
new BlockingStreamObserver<>(serverCallStreamObserver);
Thread t =
new Thread(
() -> {
RunResponse response =
RunResponse.newBuilder()
.setStandardOutput(ByteString.copyFrom(new byte[1024]))
.build();
for (int i = 0; i < 100; i++) {
blockingStreamObserver.onNext(response);
sentCount.incrementAndGet();
}
blockingStreamObserver.onCompleted();
serverDone.countDown();
});
t.start();
}
};
String uniqueName = InProcessServerBuilder.generateName();
// Do not use .directExecutor here, as it makes both client and server run in the same thread.
server =
InProcessServerBuilder.forName(uniqueName)
.addService(serverImpl)
.executor(Executors.newFixedThreadPool(4))
.build()
.start();
channel =
InProcessChannelBuilder.forName(uniqueName)
.executor(Executors.newFixedThreadPool(4))
.build();
CommandServerStub stub = CommandServerGrpc.newStub(channel);
stub.run(
RunRequest.getDefaultInstance(),
new StreamObserver<RunResponse>() {
@Override
public void onNext(RunResponse value) {
if (sentCount.get() < 3) {
} else {
clientBlocks.countDown();
try {
clientUnblocks.await();
} catch (InterruptedException e) {
throw new IllegalStateException(e);
}
}
receiveCount.incrementAndGet();
}
@Override
public void onError(Throwable t) {
throw new IllegalStateException(t);
}
@Override
public void onCompleted() {
clientDone.countDown();
}
});
clientBlocks.await();
// Wait a bit for the server to (hopefully) block. If the server does not block, then this may
// be flaky.
Thread.sleep(10);
assertThat(sentCount.get()).isLessThan(5);
clientUnblocks.countDown();
serverDone.await();
clientDone.await();
server.shutdown();
server.awaitTermination();
}
@Test
public void testFlowControlClientCancel() throws Exception {
// This test attempts to verify that FlowControl unblocks if the client prematurely closes the
// connection. In that case, FlowControl should observe the onCancel event and interrupt the
// calling thread. I have observed this test failing with an intentionally introduced bug in
// FlowControl.
CountDownLatch serverDone = new CountDownLatch(1);
CountDownLatch clientDone = new CountDownLatch(1);
AtomicInteger sentCount = new AtomicInteger();
AtomicInteger receiveCount = new AtomicInteger();
CommandServerGrpc.CommandServerImplBase serverImpl =
new CommandServerGrpc.CommandServerImplBase() {
@Override
public void run(RunRequest request, StreamObserver<RunResponse> observer) {
ServerCallStreamObserver<RunResponse> serverCallStreamObserver =
(ServerCallStreamObserver<RunResponse>) observer;
BlockingStreamObserver<RunResponse> blockingStreamObserver =
new BlockingStreamObserver<>(serverCallStreamObserver);
Thread t =
new Thread(
() -> {
RunResponse response =
RunResponse.newBuilder()
.setStandardOutput(ByteString.copyFrom(new byte[1024]))
.build();
for (int i = 0; i < 100; i++) {
blockingStreamObserver.onNext(response);
sentCount.incrementAndGet();
}
// FlowControl should have interrupted the current thread after learning of
// the server
// cancel.
assertThat(Thread.currentThread().isInterrupted()).isTrue();
blockingStreamObserver.onCompleted();
serverDone.countDown();
});
t.start();
}
};
String uniqueName = InProcessServerBuilder.generateName();
// Do not use .directExecutor here, as it makes both client and server run in the same thread.
server =
InProcessServerBuilder.forName(uniqueName)
.addService(serverImpl)
.executor(Executors.newFixedThreadPool(4))
.build()
.start();
channel =
InProcessChannelBuilder.forName(uniqueName)
.executor(Executors.newFixedThreadPool(4))
.build();
CommandServerStub stub = CommandServerGrpc.newStub(channel);
stub.run(
RunRequest.getDefaultInstance(),
new StreamObserver<RunResponse>() {
@Override
public void onNext(RunResponse value) {
if (receiveCount.get() > 3) {
channel.shutdownNow();
}
receiveCount.incrementAndGet();
}
@Override
public void onError(Throwable t) {
clientDone.countDown();
}
@Override
public void onCompleted() {
clientDone.countDown();
}
});
serverDone.await();
clientDone.await();
server.shutdown();
server.awaitTermination();
}
@Test
public void testInterruptFlowControl() throws Exception {
// This test attempts to verify that FlowControl does not hang if the current thread is
// interrupted. The initial implementation of FlowControl (which was never submitted) would go
// into an infinite loop holding the lock on FlowControl. This would prevent any other thread
// from obtaining the lock on FlowControl, and hang the entire process. I have confirmed that
// this test fails with the original faulty implementation of FlowControl.
CountDownLatch serverDone = new CountDownLatch(1);
CountDownLatch clientDone = new CountDownLatch(1);
AtomicInteger sentCount = new AtomicInteger();
AtomicInteger receiveCount = new AtomicInteger();
CommandServerGrpc.CommandServerImplBase serverImpl =
new CommandServerGrpc.CommandServerImplBase() {
@Override
public void run(RunRequest request, StreamObserver<RunResponse> observer) {
ServerCallStreamObserver<RunResponse> serverCallStreamObserver =
(ServerCallStreamObserver<RunResponse>) observer;
BlockingStreamObserver<RunResponse> blockingStreamObserver =
new BlockingStreamObserver<>(serverCallStreamObserver);
Thread t =
new Thread(
() -> {
RunResponse response =
RunResponse.newBuilder()
.setStandardOutput(ByteString.copyFrom(new byte[1024]))
.build();
// We want to trigger isReady() -> false, and we use sentCount to control
// whether to
// sleep on the client side. Therefore, we only set sentCount after isReady()
// changes.
int sent = 0;
while (serverCallStreamObserver.isReady()) {
blockingStreamObserver.onNext(response);
sent++;
}
sentCount.set(sent);
// If the current thread is interrupted, the subsequent onNext calls should
// not
// hang, but complete eventually (they may block on flow control).
Thread.currentThread().interrupt();
for (int i = 0; i < 10; i++) {
blockingStreamObserver.onNext(response);
sentCount.incrementAndGet();
}
blockingStreamObserver.onCompleted();
serverDone.countDown();
});
t.start();
}
};
String uniqueName = InProcessServerBuilder.generateName();
// Do not use .directExecutor here, as it makes both client and server run in the same thread.
server =
InProcessServerBuilder.forName(uniqueName)
.addService(serverImpl)
.executor(Executors.newFixedThreadPool(4))
.build()
.start();
channel =
InProcessChannelBuilder.forName(uniqueName)
.executor(Executors.newFixedThreadPool(4))
.build();
CommandServerStub stub = CommandServerGrpc.newStub(channel);
stub.run(
RunRequest.getDefaultInstance(),
new StreamObserver<RunResponse>() {
@Override
public void onNext(RunResponse value) {
if (sentCount.get() == 0) {
try {
Thread.sleep(1);
} catch (InterruptedException e) {
throw new IllegalStateException(e);
}
}
receiveCount.incrementAndGet();
}
@Override
public void onError(Throwable t) {
throw new IllegalStateException(t);
}
@Override
public void onCompleted() {
clientDone.countDown();
}
});
serverDone.await();
clientDone.await();
assertThat(sentCount.get()).isEqualTo(receiveCount.get());
server.shutdown();
server.awaitTermination();
}
private static StreamObserver<RunResponse> createResponseObserver(
List<RunResponse> responses, CountDownLatch done) {
return new StreamObserver<RunResponse>() {
@Override
public void onNext(RunResponse value) {
responses.add(value);
}
@Override
public void onError(Throwable t) {
done.countDown();
}
@Override
public void onCompleted() {
done.countDown();
}
};
}
private static BlazeCommandResult unexpectedCommandExec(
InvocationPolicy invocationPolicy,
List<String> args,
OutErr outErr,
LockingMode lockingMode,
String clientDescription,
long firstContactTimeMillis,
Optional<List<Pair<String, String>>> startupOptionsTaggedWithBazelRc) {
throw new IllegalStateException("Command exec not expected");
}
}