xds: implement cloud-to-prod resolver (#7900)

Implemented CloudToProdNameResolver, which will be used for DirectPath with URI scheme "google-c2p". The resolver is only a wrapper that delegates name resolution either to DNS or xDS resolver depending on the environment. If it is delegating to the xDS resolver, it will send HTTP requests (to a local HTTP server) to fetch metadata that is used to generate a bootstrap config. The self-generated bootstrap will be used for xDS.

alts/build.gradle

@@ -56,7 +56,10 @@ import net.ltgt.gradle.errorprone.CheckSeverity
     it.options.errorprone.check("FutureReturnValueIgnored", CheckSeverity.OFF)
 }
 
-javadoc { exclude 'io/grpc/alts/internal/**' }
+javadoc {
+    exclude 'io/grpc/alts/internal/**'
+    exclude 'io/grpc/alts/Internal*'
+}
 
 jar {
     // Must use a different classifier to avoid conflicting with shadowJar

alts/src/main/java/io/grpc/alts/AltsChannelCredentials.java

@@ -93,7 +93,7 @@ public ChannelCredentials build() {
     }
 
     InternalProtocolNegotiator.ClientFactory buildProtocolNegotiatorFactory() {
-      if (!CheckGcpEnvironment.isOnGcp()) {
+      if (!InternalCheckGcpEnvironment.isOnGcp()) {
         if (enableUntrustedAlts) {
           logger.log(
               Level.WARNING,

alts/src/main/java/io/grpc/alts/AltsServerCredentials.java

@@ -76,7 +76,7 @@ public ServerCredentials build() {
     }
 
     InternalProtocolNegotiator.ProtocolNegotiator buildProtocolNegotiator() {
-      if (!CheckGcpEnvironment.isOnGcp()) {
+      if (!InternalCheckGcpEnvironment.isOnGcp()) {
         if (enableUntrustedAlts) {
           logger.log(
               Level.WARNING,

alts/src/main/java/io/grpc/alts/ComputeEngineChannelCredentials.java

@@ -49,7 +49,7 @@ public static ChannelCredentials create() {
     ChannelCredentials nettyCredentials =
         InternalNettyChannelCredentials.create(createClientFactory());
     CallCredentials callCredentials;
-    if (CheckGcpEnvironment.isOnGcp()) {
+    if (InternalCheckGcpEnvironment.isOnGcp()) {
       callCredentials = MoreCallCredentials.from(ComputeEngineCredentials.create());
     } else {
       callCredentials = new FailingCallCredentials(

alts/src/main/java/io/grpc/alts/CheckGcpEnvironment.java → alts/src/main/java/io/grpc/alts/InternalCheckGcpEnvironment.java

@@ -19,6 +19,7 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.common.annotations.VisibleForTesting;
+import io.grpc.Internal;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
@@ -28,18 +29,27 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-/** Class for checking if the system is running on Google Cloud Platform (GCP). */
-final class CheckGcpEnvironment {
+/**
+ * Class for checking if the system is running on Google Cloud Platform (GCP).
+ * This is intended for usage internal to the gRPC team. If you *really* think you need
+ * to use this, contact the gRPC team first.
+ */
+@Internal
+public final class InternalCheckGcpEnvironment {
 
-  private static final Logger logger = Logger.getLogger(CheckGcpEnvironment.class.getName());
+  private static final Logger logger =
+      Logger.getLogger(InternalCheckGcpEnvironment.class.getName());
   private static final String DMI_PRODUCT_NAME = "/sys/class/dmi/id/product_name";
   private static final String WINDOWS_COMMAND = "powershell.exe";
   private static Boolean cachedResult = null;
 
   // Construct me not!
-  private CheckGcpEnvironment() {}
+  private InternalCheckGcpEnvironment() {}
 
-  static synchronized boolean isOnGcp() {
+  /**
+   * Returns {@code true} if currently running on Google Cloud Platform (GCP).
+   */
+  public static synchronized boolean isOnGcp() {
     if (cachedResult == null) {
       cachedResult = isRunningOnGcp();
     }

alts/src/test/java/io/grpc/alts/CheckGcpEnvironmentTest.java → alts/src/test/java/io/grpc/alts/InternalCheckGcpEnvironmentTest.java

@@ -26,37 +26,37 @@
 import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
-public final class CheckGcpEnvironmentTest {
+public final class InternalCheckGcpEnvironmentTest {
 
   @Test
   public void checkGcpLinuxPlatformData() throws Exception {
     BufferedReader reader;
     reader = new BufferedReader(new StringReader("HP Z440 Workstation"));
-    assertFalse(CheckGcpEnvironment.checkProductNameOnLinux(reader));
+    assertFalse(InternalCheckGcpEnvironment.checkProductNameOnLinux(reader));
     reader = new BufferedReader(new StringReader("Google"));
-    assertTrue(CheckGcpEnvironment.checkProductNameOnLinux(reader));
+    assertTrue(InternalCheckGcpEnvironment.checkProductNameOnLinux(reader));
     reader = new BufferedReader(new StringReader("Google Compute Engine"));
-    assertTrue(CheckGcpEnvironment.checkProductNameOnLinux(reader));
+    assertTrue(InternalCheckGcpEnvironment.checkProductNameOnLinux(reader));
     reader = new BufferedReader(new StringReader("Google Compute Engine    "));
-    assertTrue(CheckGcpEnvironment.checkProductNameOnLinux(reader));
+    assertTrue(InternalCheckGcpEnvironment.checkProductNameOnLinux(reader));
   }
 
   @Test
   public void checkGcpWindowsPlatformData() throws Exception {
     BufferedReader reader;
     reader = new BufferedReader(new StringReader("Product : Google"));
-    assertFalse(CheckGcpEnvironment.checkBiosDataOnWindows(reader));
+    assertFalse(InternalCheckGcpEnvironment.checkBiosDataOnWindows(reader));
     reader = new BufferedReader(new StringReader("Manufacturer : LENOVO"));
-    assertFalse(CheckGcpEnvironment.checkBiosDataOnWindows(reader));
+    assertFalse(InternalCheckGcpEnvironment.checkBiosDataOnWindows(reader));
     reader = new BufferedReader(new StringReader("Manufacturer : Google Compute Engine"));
-    assertFalse(CheckGcpEnvironment.checkBiosDataOnWindows(reader));
+    assertFalse(InternalCheckGcpEnvironment.checkBiosDataOnWindows(reader));
     reader = new BufferedReader(new StringReader("Manufacturer : Google"));
-    assertTrue(CheckGcpEnvironment.checkBiosDataOnWindows(reader));
+    assertTrue(InternalCheckGcpEnvironment.checkBiosDataOnWindows(reader));
     reader = new BufferedReader(new StringReader("Manufacturer:Google"));
-    assertTrue(CheckGcpEnvironment.checkBiosDataOnWindows(reader));
+    assertTrue(InternalCheckGcpEnvironment.checkBiosDataOnWindows(reader));
     reader = new BufferedReader(new StringReader("Manufacturer :   Google    "));
-    assertTrue(CheckGcpEnvironment.checkBiosDataOnWindows(reader));
+    assertTrue(InternalCheckGcpEnvironment.checkBiosDataOnWindows(reader));
     reader = new BufferedReader(new StringReader("BIOSVersion : 1.0\nManufacturer : Google\n"));
-    assertTrue(CheckGcpEnvironment.checkBiosDataOnWindows(reader));
+    assertTrue(InternalCheckGcpEnvironment.checkBiosDataOnWindows(reader));
   }
 }

xds/src/main/java/io/grpc/xds/Bootstrapper.java

@@ -31,19 +31,26 @@
  * Loads configuration information to bootstrap gRPC's integration of xDS protocol.
  */
 @Internal
-public interface Bootstrapper {
+public abstract class Bootstrapper {
 
   /**
-   * Returns configurations from bootstrap.
+   * Returns system-loaded bootstrap configuration.
    */
-  BootstrapInfo bootstrap() throws XdsInitializationException;
+  public abstract BootstrapInfo bootstrap() throws XdsInitializationException;
+
+  /**
+   * Returns bootstrap configuration given by the raw data in JSON format.
+   */
+  BootstrapInfo bootstrap(Map<String, ?> rawData) throws XdsInitializationException {
+    throw new UnsupportedOperationException();
+  }
 
   /**
    * Data class containing xDS server information, such as server URI and channel credentials
    * to be used for communication.
    */
   @Internal
-  class ServerInfo {
+  static class ServerInfo {
     private final String target;
     private final ChannelCredentials channelCredentials;
     private final boolean useProtocolV3;
@@ -73,7 +80,7 @@ boolean isUseProtocolV3() {
    * Map that represents the config for that plugin.
    */
   @Internal
-  class CertificateProviderInfo {
+  public static class CertificateProviderInfo {
     private final String pluginName;
     private final Map<String, ?> config;
 
@@ -95,7 +102,7 @@ public String getPluginName() {
    * Data class containing the results of reading bootstrap.
    */
   @Internal
-  class BootstrapInfo {
+  public static class BootstrapInfo {
     private List<ServerInfo> servers;
     private final Node node;
     @Nullable private final Map<String, CertificateProviderInfo> certProviders;

xds/src/main/java/io/grpc/xds/BootstrapperImpl.java

@@ -43,7 +43,7 @@
  * A {@link Bootstrapper} implementation that reads xDS configurations from local file system.
  */
 @Internal
-public class BootstrapperImpl implements Bootstrapper {
+public class BootstrapperImpl extends Bootstrapper {
 
   private static final String BOOTSTRAP_PATH_SYS_ENV_VAR = "GRPC_XDS_BOOTSTRAP";
   @VisibleForTesting
@@ -80,70 +80,49 @@ public BootstrapperImpl() {
    *   <li>Java System Property value of "io.grpc.xds.bootstrap_value"</li>
    * </ol>
    */
+  @SuppressWarnings("unchecked")
   @Override
   public BootstrapInfo bootstrap() throws XdsInitializationException {
     String filePath =
         bootstrapPathFromEnvVar != null ? bootstrapPathFromEnvVar : bootstrapPathFromSysProp;
-    String rawBootstrap;
+    String fileContent;
     if (filePath != null) {
       logger.log(XdsLogLevel.INFO, "Reading bootstrap file from {0}", filePath);
       try {
-        rawBootstrap = reader.readFile(filePath);
+        fileContent = reader.readFile(filePath);
       } catch (IOException e) {
         throw new XdsInitializationException("Fail to read bootstrap file", e);
       }
     } else {
-      rawBootstrap = bootstrapConfigFromEnvVar != null
+      fileContent = bootstrapConfigFromEnvVar != null
           ? bootstrapConfigFromEnvVar : bootstrapConfigFromSysProp;
     }
-    if (rawBootstrap != null) {
-      return parseConfig(rawBootstrap);
-    }
-    throw new XdsInitializationException(
-        "Cannot find bootstrap configuration\n"
-            + "Environment variables searched:\n"
-            + "- " + BOOTSTRAP_PATH_SYS_ENV_VAR + "\n"
-            + "- " + BOOTSTRAP_CONFIG_SYS_ENV_VAR + "\n\n"
-            + "Java System Properties searched:\n"
-            + "- " + BOOTSTRAP_PATH_SYS_PROPERTY + "\n"
-            + "- " + BOOTSTRAP_CONFIG_SYS_PROPERTY_VAR + "\n\n");
-  }
-
-  @VisibleForTesting
-  void setFileReader(FileReader reader) {
-    this.reader = reader;
-  }
-
-  /**
-   * Reads the content of the file with the given path in the file system.
-   */
-  interface FileReader {
-    String readFile(String path) throws IOException;
-  }
-
-  private enum LocalFileReader implements FileReader {
-    INSTANCE;
-
-    @Override
-    public String readFile(String path) throws IOException {
-      return new String(Files.readAllBytes(Paths.get(path)), StandardCharsets.UTF_8);
+    if (fileContent == null) {
+      throw new XdsInitializationException(
+          "Cannot find bootstrap configuration\n"
+              + "Environment variables searched:\n"
+              + "- " + BOOTSTRAP_PATH_SYS_ENV_VAR + "\n"
+              + "- " + BOOTSTRAP_CONFIG_SYS_ENV_VAR + "\n\n"
+              + "Java System Properties searched:\n"
+              + "- " + BOOTSTRAP_PATH_SYS_PROPERTY + "\n"
+              + "- " + BOOTSTRAP_CONFIG_SYS_PROPERTY_VAR + "\n\n");
     }
-  }
 
-  /** Parses a raw string into {@link BootstrapInfo}. */
-  @SuppressWarnings("unchecked")
-  private BootstrapInfo parseConfig(String rawData) throws XdsInitializationException {
-    logger.log(XdsLogLevel.INFO, "Reading bootstrap information");
+    logger.log(XdsLogLevel.INFO, "Reading bootstrap from " + filePath);
     Map<String, ?> rawBootstrap;
     try {
-      rawBootstrap = (Map<String, ?>) JsonParser.parse(rawData);
+      rawBootstrap = (Map<String, ?>) JsonParser.parse(fileContent);
     } catch (IOException e) {
       throw new XdsInitializationException("Failed to parse JSON", e);
     }
     logger.log(XdsLogLevel.DEBUG, "Bootstrap configuration:\n{0}", rawBootstrap);
+    return bootstrap(rawBootstrap);
+  }
 
+  @Override
+  BootstrapInfo bootstrap(Map<String, ?> rawData) throws XdsInitializationException {
     List<ServerInfo> servers = new ArrayList<>();
-    List<?> rawServerConfigs = JsonUtil.getList(rawBootstrap, "xds_servers");
+    List<?> rawServerConfigs = JsonUtil.getList(rawData, "xds_servers");
     if (rawServerConfigs == null) {
       throw new XdsInitializationException("Invalid bootstrap: 'xds_servers' does not exist.");
     }
@@ -179,7 +158,7 @@ private BootstrapInfo parseConfig(String rawData) throws XdsInitializationExcept
     }
 
     Node.Builder nodeBuilder = Node.newBuilder();
-    Map<String, ?> rawNode = JsonUtil.getObject(rawBootstrap, "node");
+    Map<String, ?> rawNode = JsonUtil.getObject(rawData, "node");
     if (rawNode != null) {
       String id = JsonUtil.getString(rawNode, "id");
       if (id != null) {
@@ -222,7 +201,7 @@ private BootstrapInfo parseConfig(String rawData) throws XdsInitializationExcept
     nodeBuilder.setUserAgentVersion(buildVersion.getImplementationVersion());
     nodeBuilder.addClientFeatures(CLIENT_FEATURE_DISABLE_OVERPROVISIONING);
 
-    Map<String, ?> certProvidersBlob = JsonUtil.getObject(rawBootstrap, "certificate_providers");
+    Map<String, ?> certProvidersBlob = JsonUtil.getObject(rawData, "certificate_providers");
     Map<String, CertificateProviderInfo> certProviders = null;
     if (certProvidersBlob != null) {
       certProviders = new HashMap<>(certProvidersBlob.size());
@@ -236,11 +215,32 @@ private BootstrapInfo parseConfig(String rawData) throws XdsInitializationExcept
         certProviders.put(name, certificateProviderInfo);
       }
     }
-    String grpcServerResourceId = JsonUtil.getString(rawBootstrap, "grpc_server_resource_name_id");
+    String grpcServerResourceId = JsonUtil.getString(rawData, "grpc_server_resource_name_id");
     return new BootstrapInfo(servers, nodeBuilder.build(), certProviders, grpcServerResourceId);
   }
 
-  static <T> T checkForNull(T value, String fieldName) throws XdsInitializationException {
+  @VisibleForTesting
+  void setFileReader(FileReader reader) {
+    this.reader = reader;
+  }
+
+  /**
+   * Reads the content of the file with the given path in the file system.
+   */
+  interface FileReader {
+    String readFile(String path) throws IOException;
+  }
+
+  private enum LocalFileReader implements FileReader {
+    INSTANCE;
+
+    @Override
+    public String readFile(String path) throws IOException {
+      return new String(Files.readAllBytes(Paths.get(path)), StandardCharsets.UTF_8);
+    }
+  }
+
+  private static <T> T checkForNull(T value, String fieldName) throws XdsInitializationException {
     if (value == null) {
       throw new XdsInitializationException(
           "Invalid bootstrap: '" + fieldName + "' does not exist.");