fix: check Compute Engine environment for DirectPath (#1250)

Author: mohanli-ml

gax-grpc/src/main/java/com/google/api/gax/grpc/InstantiatingGrpcChannelProvider.java

@@ -44,10 +44,12 @@
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.io.CharStreams;
 import io.grpc.ManagedChannel;
 import io.grpc.ManagedChannelBuilder;
 import io.grpc.alts.ComputeEngineChannelBuilder;
 import java.io.IOException;
+import java.io.InputStreamReader;
 import java.util.Map;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
@@ -74,6 +76,8 @@ public final class InstantiatingGrpcChannelProvider implements TransportChannelP
  static final long DIRECT_PATH_KEEP_ALIVE_TIMEOUT_SECONDS = 20;
  // reduce the thundering herd problem of too many channels trying to (re)connect at the same time
  static final int MAX_POOL_SIZE = 1000;
+ static final String GCE_PRODUCTION_NAME_PRIOR_2016 = "Google";
+ static final String GCE_PRODUCTION_NAME_AFTER_2016 = "Google Compute Engine";
 
  private final int processorCount;
  private final Executor executor;
@@ -234,6 +238,26 @@ private boolean isDirectPathEnabled(String serviceAddress) {
  return false;
  }
 
+ // DirectPath should only be used on Compute Engine.
+ // Notice Windows is supported for now.
+ static boolean isOnComputeEngine() {
+ String osName = System.getProperty("os.name");
+ if ("Linux".equals(osName)) {
+ String cmd = "cat /sys/class/dmi/id/product_name";
+ try {
+ Process process = Runtime.getRuntime().exec(new String[] {"/bin/sh", "-c", cmd});
+ process.waitFor();
+ String result =
+ CharStreams.toString(new InputStreamReader(process.getInputStream(), "UTF-8"));
+ return result.contains(GCE_PRODUCTION_NAME_PRIOR_2016)
+ || result.contains(GCE_PRODUCTION_NAME_AFTER_2016);
+ } catch (IOException | InterruptedException e) {
+ return false;
+ }
+ }
+ return false;
+ }
+
  private ManagedChannel createSingleChannel() throws IOException {
  GrpcHeaderInterceptor headerInterceptor =
  new GrpcHeaderInterceptor(headerProvider.getHeaders());
@@ -250,7 +274,9 @@ private ManagedChannel createSingleChannel() throws IOException {
  ManagedChannelBuilder builder;
 
  // TODO(weiranf): Add API in ComputeEngineCredentials to check default service account.
- if (isDirectPathEnabled(serviceAddress) && credentials instanceof ComputeEngineCredentials) {
+ if (isDirectPathEnabled(serviceAddress)
+ && credentials instanceof ComputeEngineCredentials
+ && isOnComputeEngine()) {
  builder = ComputeEngineChannelBuilder.forAddress(serviceAddress, port);
  // Set default keepAliveTime and keepAliveTimeout when directpath environment is enabled.
  // Will be overridden by user defined values if any.

gax-grpc/src/test/java/com/google/api/gax/grpc/InstantiatingGrpcChannelProviderTest.java

@@ -219,7 +219,11 @@ public void testWithGCECredentials() throws IOException {
  ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder> channelConfigurator =
  new ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder>() {
  public ManagedChannelBuilder apply(ManagedChannelBuilder channelBuilder) {
- assertThat(channelBuilder instanceof ComputeEngineChannelBuilder).isTrue();
+ if (InstantiatingGrpcChannelProvider.isOnComputeEngine()) {
+ assertThat(channelBuilder instanceof ComputeEngineChannelBuilder).isTrue();
+ } else {
+ assertThat(channelBuilder instanceof ComputeEngineChannelBuilder).isFalse();
+ }
  return channelBuilder;
  }
  };
@@ -234,7 +238,11 @@ public ManagedChannelBuilder apply(ManagedChannelBuilder channelBuilder) {
  .withEndpoint("localhost:8080");
 
  assertThat(provider.needsCredentials()).isTrue();
- provider = provider.withCredentials(ComputeEngineCredentials.create());
+ if (InstantiatingGrpcChannelProvider.isOnComputeEngine()) {
+ provider = provider.withCredentials(ComputeEngineCredentials.create());
+ } else {
+ provider = provider.withCredentials(CloudShellCredentials.create(3000));
+ }
  assertThat(provider.needsCredentials()).isFalse();
 
  provider.getTransportChannel().shutdownNow();