Use NoCredentialsProvider when firestore emulator enabled.

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/firestore/GcpFirestoreAutoConfiguration.java

@@ -19,6 +19,7 @@
 import java.io.IOException;
 
 import com.google.api.gax.core.CredentialsProvider;
+import com.google.api.gax.core.NoCredentialsProvider;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
 import com.google.cloud.firestore.Firestore;
 import com.google.cloud.firestore.FirestoreOptions;
@@ -81,9 +82,15 @@ public class GcpFirestoreAutoConfiguration {
 				? gcpFirestoreProperties.getProjectId()
 				: projectIdProvider.getProjectId();
 
-		this.credentialsProvider = (gcpFirestoreProperties.getCredentials().hasKey()
-				? new DefaultCredentialsProvider(gcpFirestoreProperties)
-				: credentialsProvider);
+		if (gcpFirestoreProperties.getEmulator().isEnabled()) {
+			// if the emulator is enabled, create CredentialsProvider for this particular case.
+			this.credentialsProvider = NoCredentialsProvider.create();
+		}
+		else {
+			this.credentialsProvider = (gcpFirestoreProperties.getCredentials().hasKey()
+					? new DefaultCredentialsProvider(gcpFirestoreProperties)
+					: credentialsProvider);
+		}
 
 		this.hostPort = gcpFirestoreProperties.getHostPort();
 		this.firestoreRootPath = String.format(ROOT_PATH_FORMAT, this.projectId);
@@ -109,6 +116,10 @@ public Firestore firestore(FirestoreOptions firestoreOptions) {
 		return firestoreOptions.getService();
 	}
 
+	CredentialsProvider getCredentialsProvider() {
+		return credentialsProvider;
+	}
+
 	/**
 	 * The Firestore reactive template and data repositories support auto-configuration.
 	 */
@@ -160,4 +171,5 @@ public ManagedChannel firestoreManagedChannel() {
 					.build();
 		}
 	}
+
 }

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/firestore/GcpFirestoreProperties.java

@@ -45,6 +45,9 @@ public class GcpFirestoreProperties implements CredentialsSupplier {
 	 */
 	private String hostPort = "firestore.googleapis.com:443";
 
+	@NestedConfigurationProperty
+	private FirestoreEmulatorProperties emulator = new FirestoreEmulatorProperties();
+
 	@Override
 	public Credentials getCredentials() {
 		return this.credentials;
@@ -65,4 +68,29 @@ public String getHostPort() {
 	public void setHostPort(String hostPort) {
 		this.hostPort = hostPort;
 	}
+
+	public FirestoreEmulatorProperties getEmulator() {
+		return emulator;
+	}
+
+	public void setEmulator(FirestoreEmulatorProperties emulator) {
+		this.emulator = emulator;
+	}
+
+	public static class FirestoreEmulatorProperties {
+
+		/**
+		 * Enables autoconfiguration to use the Firestore emulator.
+		 * If this is set to true, then you should set the spring.cloud.gcp.firestore.host-port to the host:port of your locally running emulator instance
+		 */
+		private boolean enabled = false;
+
+		public boolean isEnabled() {
+			return enabled;
+		}
+
+		public void setEnabled(boolean enabled) {
+			this.enabled = enabled;
+		}
+	}
 }

spring-cloud-gcp-autoconfigure/src/test/java/com/google/cloud/spring/autoconfigure/firestore/GcpFirestoreEmulatorAutoConfigurationTests.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2017-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.cloud.spring.autoconfigure.firestore;
+
+import com.google.api.gax.core.CredentialsProvider;
+import com.google.api.gax.core.NoCredentialsProvider;
+import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
+import com.google.auth.Credentials;
+import com.google.cloud.firestore.Firestore;
+import com.google.cloud.firestore.FirestoreOptions;
+import com.google.cloud.spring.autoconfigure.core.GcpContextAutoConfiguration;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for the Firestore emulator config.
+ *
+ * @author Gary Wong
+ */
+class GcpFirestoreEmulatorAutoConfigurationTests {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(
+					GcpContextAutoConfiguration.class,
+					GcpFirestoreEmulatorAutoConfiguration.class,
+					GcpFirestoreAutoConfiguration.class));
+
+	@Test
+	void testEmulatorEnabledConfig() {
+		this.contextRunner.withPropertyValues(
+				"spring.cloud.gcp.firestore.projectId=test-project",
+				"spring.cloud.gcp.firestore.emulator.enabled=true",
+				"spring.cloud.gcp.firestore.host-port=localhost:8080"
+		).run(context -> {
+			CredentialsProvider defaultCredentialsProvider = context.getBean(CredentialsProvider.class);
+			assertThat(defaultCredentialsProvider).isNotInstanceOf(NoCredentialsProvider.class);
+
+			GcpFirestoreAutoConfiguration firestoreAutoConfiguration = context.getBean(GcpFirestoreAutoConfiguration.class);
+			assertThat(firestoreAutoConfiguration.getCredentialsProvider()).isInstanceOf(NoCredentialsProvider.class);
+
+			FirestoreOptions datastoreOptions = context.getBean(Firestore.class).getOptions();
+			assertThat(datastoreOptions.getProjectId()).isEqualTo("test-project");
+
+			InstantiatingGrpcChannelProvider channelProvider = (InstantiatingGrpcChannelProvider) datastoreOptions.getTransportChannelProvider();
+			assertThat(channelProvider.getEndpoint()).isEqualTo("localhost:8080");
+		});
+	}
+
+	@Test
+	void testDefaultConfig() {
+		CredentialsProvider mockedCredentialsProvider = () -> mock(Credentials.class);
+
+		this.contextRunner.withPropertyValues(
+				"spring.cloud.gcp.firestore.projectId=test-project"
+		).withBean("mockedCredentialsProvider", CredentialsProvider.class, () -> mockedCredentialsProvider)
+		.run(context -> {
+			GcpFirestoreProperties gcpFirestoreProperties = context.getBean(GcpFirestoreProperties.class);
+			assertThat(gcpFirestoreProperties.getEmulator().isEnabled()).isFalse();
+
+			GcpFirestoreAutoConfiguration firestoreAutoConfiguration = context.getBean(GcpFirestoreAutoConfiguration.class);
+			assertThat(firestoreAutoConfiguration.getCredentialsProvider()).isEqualTo(mockedCredentialsProvider);
+
+			FirestoreOptions datastoreOptions = context.getBean(Firestore.class).getOptions();
+			assertThat(datastoreOptions.getProjectId()).isEqualTo("test-project");
+
+			InstantiatingGrpcChannelProvider channelProvider = (InstantiatingGrpcChannelProvider) datastoreOptions.getTransportChannelProvider();
+			assertThat(channelProvider.getEndpoint()).isEqualTo("firestore.googleapis.com:443");
+		});
+	}
+}