feat: allow opt-in for gRPC, have datastore-v1-proto-client as default (#1400)

* feat: allow opt-in for gRPC, have datastore-v1-proto-client as default transport

* chore: update concepts test (#1382)

Fixes #1379

(cherry picked from commit 9818aee)

* fix host setting logic

* fix test

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* update test

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: kolea2

README.md

@@ -50,20 +50,20 @@ If you are using Maven without the BOM, add this to your dependencies:
 If you are using Gradle 5.x or later, add this to your dependencies:
 
 ```Groovy
-implementation platform('com.google.cloud:libraries-bom:26.34.0')
+implementation platform('com.google.cloud:libraries-bom:26.37.0')
 
 implementation 'com.google.cloud:google-cloud-datastore'
 ```
 If you are using Gradle without BOM, add this to your dependencies:
 
 ```Groovy
-implementation 'com.google.cloud:google-cloud-datastore:2.18.5'
+implementation 'com.google.cloud:google-cloud-datastore:2.19.0'
 ```
 
 If you are using SBT, add this to your dependencies:
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-datastore" % "2.18.5"
+libraryDependencies += "com.google.cloud" % "google-cloud-datastore" % "2.19.0"
 ```
 <!-- {x-version-update-end} -->
 
@@ -380,7 +380,7 @@ Java is a registered trademark of Oracle and/or its affiliates.
 [kokoro-badge-link-5]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-datastore/java11.html
 [stability-image]: https://img.shields.io/badge/stability-stable-green
 [maven-version-image]: https://img.shields.io/maven-central/v/com.google.cloud/google-cloud-datastore.svg
-[maven-version-link]: https://central.sonatype.com/artifact/com.google.cloud/google-cloud-datastore/2.18.5
+[maven-version-link]: https://central.sonatype.com/artifact/com.google.cloud/google-cloud-datastore/2.19.0
 [authentication]: https://github.com/googleapis/google-cloud-java#authentication
 [auth-scopes]: https://developers.google.com/identity/protocols/oauth2/scopes
 [predefined-iam-roles]: https://cloud.google.com/iam/docs/understanding-roles#predefined_roles

google-cloud-datastore/pom.xml

@@ -42,6 +42,10 @@
       <groupId>com.google.api.grpc</groupId>
       <artifactId>proto-google-cloud-datastore-admin-v1</artifactId>
     </dependency>
+    <dependency>
+      <groupId>com.google.cloud.datastore</groupId>
+      <artifactId>datastore-v1-proto-client</artifactId>
+    </dependency>
     <dependency>
       <groupId>io.grpc</groupId>
       <artifactId>grpc-api</artifactId>
@@ -102,6 +106,10 @@
       <groupId>com.google.oauth-client</groupId>
       <artifactId>google-oauth-client</artifactId>
     </dependency>
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-oauth2-http</artifactId>
+    </dependency>
     <dependency>
       <groupId>io.opencensus</groupId>
       <artifactId>opencensus-api</artifactId>

google-cloud-datastore/src/main/java/com/google/cloud/datastore/DatastoreOptions.java

@@ -18,6 +18,7 @@
 
 import static com.google.cloud.datastore.Validator.validateNamespace;
 
+import com.google.api.core.BetaApi;
 import com.google.api.gax.core.CredentialsProvider;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
 import com.google.api.gax.rpc.TransportChannelProvider;
@@ -74,15 +75,8 @@ public ServiceRpc create(DatastoreOptions options) {
       try {
         if (options.getTransportOptions() instanceof GrpcTransportOptions) {
           return new GrpcDatastoreRpc(options);
-        } else if (options.getTransportOptions() instanceof HttpTransportOptions) {
-          // todo see if we can remove this check
-          if (DatastoreUtils.isEmulator(options)) {
-            throw new IllegalArgumentException("Only GRPC channels are allowed for emulator.");
-          }
-          return new HttpDatastoreRpc(options);
         } else {
-          throw new IllegalArgumentException(
-              "unknown transport type: " + options.getTransportOptions());
+          return new HttpDatastoreRpc(options);
         }
       } catch (IOException e) {
         throw new RuntimeException(e);
@@ -96,6 +90,8 @@ public static class Builder extends ServiceOptions.Builder<Datastore, DatastoreO
     private String databaseId;
     private TransportChannelProvider channelProvider = null;
     private CredentialsProvider credentialsProvider = null;
+    private String host;
+    private TransportOptions transportOptions;
 
     private Builder() {}
 
@@ -109,15 +105,33 @@ private Builder(DatastoreOptions options) {
 
     @Override
     public Builder setTransportOptions(TransportOptions transportOptions) {
+      if (!(transportOptions instanceof HttpTransportOptions)) {
+        throw new IllegalArgumentException(
+            "Only http transport is allowed for " + API_SHORT_NAME + ".");
+      }
+      this.transportOptions = transportOptions;
+      return super.setTransportOptions(transportOptions);
+    }
+
+    @BetaApi
+    public Builder setTransportOptions(GrpcTransportOptions transportOptions) {
+      this.transportOptions = transportOptions;
       return super.setTransportOptions(transportOptions);
     }
 
+    @Override
+    public Builder setHost(String host) {
+      this.host = host;
+      return super.setHost(host);
+    }
+
     /**
      * Sets the {@link TransportChannelProvider} to use with this Datastore client.
      *
      * @param channelProvider A InstantiatingGrpcChannelProvider object that defines the transport
      *     provider for this client.
      */
+    @BetaApi
     public Builder setChannelProvider(TransportChannelProvider channelProvider) {
       this.channelProvider = validateChannelProvider(channelProvider);
       return this;
@@ -129,13 +143,17 @@ public Builder setChannelProvider(TransportChannelProvider channelProvider) {
      * @param credentialsProvider A CredentialsProvider object that defines the credential provider
      *     for this client.
      */
+    @BetaApi
     public Builder setCredentialsProvider(CredentialsProvider credentialsProvider) {
       this.credentialsProvider = credentialsProvider;
       return this;
     }
 
     @Override
     public DatastoreOptions build() {
+      if (this.host == null && this.transportOptions instanceof GrpcTransportOptions) {
+        this.setHost(DatastoreSettings.getDefaultEndpoint());
+      }
       return new DatastoreOptions(this);
     }
 
@@ -153,7 +171,7 @@ public Builder setDatabaseId(String databaseId) {
 
   private static TransportChannelProvider validateChannelProvider(
       TransportChannelProvider channelProvider) {
-    if (!(channelProvider instanceof InstantiatingGrpcChannelProvider)) {
+    if (channelProvider != null && !(channelProvider instanceof InstantiatingGrpcChannelProvider)) {
       throw new IllegalArgumentException(
           "Only GRPC channels are allowed for " + API_SHORT_NAME + ".");
     }
@@ -165,7 +183,6 @@ private DatastoreOptions(Builder builder) {
     namespace = MoreObjects.firstNonNull(builder.namespace, defaultNamespace());
     databaseId = MoreObjects.firstNonNull(builder.databaseId, DEFAULT_DATABASE_ID);
 
-    // todo see if we can update this
     if (getTransportOptions() instanceof HttpTransportOptions
         && (builder.channelProvider != null || builder.credentialsProvider != null)) {
       throw new IllegalArgumentException(
@@ -195,7 +212,7 @@ public TransportChannelProvider getTransportChannelProvider() {
   @Override
   protected String getDefaultHost() {
     String host = System.getProperty(LOCAL_HOST_ENV_VAR, System.getenv(LOCAL_HOST_ENV_VAR));
-    return host != null ? host : DatastoreSettings.getDefaultEndpoint();
+    return host != null ? host : com.google.datastore.v1.client.DatastoreFactory.DEFAULT_HOST;
   }
 
   @Override
@@ -222,8 +239,8 @@ public TransportOptions getDefaultTransportOptions() {
       return TRANSPORT_OPTIONS;
     }
 
-    public static GrpcTransportOptions.Builder getDefaultTransportOptionsBuilder() {
-      return GrpcTransportOptions.newBuilder();
+    public static HttpTransportOptions.Builder getDefaultTransportOptionsBuilder() {
+      return HttpTransportOptions.newBuilder();
     }
   }