feat: add support for Firestore database id configuration

docs/src/main/asciidoc/datastore.adoc

@@ -68,7 +68,7 @@ The following configuration options are available:
 | Name | Description | Required | Default value
 | `spring.cloud.gcp.datastore.enabled` | Enables the Cloud Datastore client | No | `true`
 | `spring.cloud.gcp.datastore.project-id` | Google Cloud project ID where the Google Cloud Datastore API is hosted, if different from the one in the <<spring-cloud-gcp-core,Spring Framework on Google Cloud Core Module>> | No |
-| `spring.cloud.gcp.datastore.database-id` | Google Cloud project can host multiple databases. You can specify which database will be used. | No |
+| `spring.cloud.gcp.datastore.database-id` | Google Cloud project can host multiple databases. You can specify which database will be used. If not specified, the database id will be "(default)". | No |
 | `spring.cloud.gcp.datastore.credentials.location` | OAuth2 credentials for authenticating with the Google Cloud Datastore API, if different from the ones in the <<spring-cloud-gcp-core,Spring Framework on Google Cloud Core Module>> | No |
 | `spring.cloud.gcp.datastore.credentials.encoded-key` | Base64-encoded OAuth2 credentials for authenticating with the Google Cloud Datastore API, if different from the ones in the <<spring-cloud-gcp-core,Spring Framework on Google Cloud Core Module>> | No |
 | `spring.cloud.gcp.datastore.credentials.scopes` | https://developers.google.com/identity/protocols/googlescopes[OAuth2 scope] for Spring Framework on Google CloudDatastore credentials | No | https://www.googleapis.com/auth/datastore

docs/src/main/asciidoc/firestore.adoc

@@ -54,6 +54,7 @@ The Spring Boot starter for Google Cloud Firestore provides the following config
 | Name | Description | Required | Default value
 | `spring.cloud.gcp.firestore.enabled` | Enables or disables Firestore auto-configuration | No | `true`
 | `spring.cloud.gcp.firestore.project-id` | Google Cloud project ID where the Google Cloud Firestore API is hosted, if different from the one in the <<spring-cloud-gcp-core,Spring Framework on Google Cloud Core Module>> | No |
+| `spring.cloud.gcp.firestore.database-id` | Google Cloud project can host multiple databases. You can specify which database will be used. If not specified, the database id will be "(default)". | No |
 | `spring.cloud.gcp.firestore.emulator.enabled` | Enables the usage of an 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 | No | `false`
 | `spring.cloud.gcp.firestore.host-port` | The host and port of the Firestore service; can be overridden to specify connecting to an already-running https://firebase.google.com/docs/emulator-suite/install_and_configure[Firestore emulator] instance. | No | `firestore.googleapis.com:443` (the host/port of official Firestore service)
 | `spring.cloud.gcp.firestore.credentials.location` | OAuth2 credentials for authenticating with the Google Cloud Firestore API, if different from the ones in the <<spring-cloud-gcp-core,Spring Framework on Google Cloud Core Module>> | No |

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

@@ -61,6 +61,8 @@ public class GcpFirestoreAutoConfiguration {
 
   private final String projectId;
 
+  private final String databaseId;
+
   private final CredentialsProvider credentialsProvider;
 
   private final String hostPort;
@@ -74,6 +76,7 @@ public class GcpFirestoreAutoConfiguration {
       throws IOException {
 
     this.projectId = gcpFirestoreProperties.getResolvedProjectId(projectIdProvider);
+    this.databaseId = gcpFirestoreProperties.getDatabaseId();
 
     if (gcpFirestoreProperties.getEmulator().isEnabled()) {
       // if the emulator is enabled, create CredentialsProvider for this particular case.
@@ -92,13 +95,19 @@ public class GcpFirestoreAutoConfiguration {
   @Bean
   @ConditionalOnMissingBean
   public FirestoreOptions firestoreOptions() {
-    return FirestoreOptions.getDefaultInstance().toBuilder()
+
+    FirestoreOptions.Builder builder = FirestoreOptions.getDefaultInstance().toBuilder()
         .setCredentialsProvider(this.credentialsProvider)
         .setProjectId(this.projectId)
         .setHeaderProvider(USER_AGENT_HEADER_PROVIDER)
         .setChannelProvider(
-            InstantiatingGrpcChannelProvider.newBuilder().setEndpoint(this.hostPort).build())
-        .build();
+            InstantiatingGrpcChannelProvider.newBuilder().setEndpoint(this.hostPort).build());
+
+    if (databaseId != null) {
+      builder.setDatabaseId(databaseId);
+    }
+
+    return builder.build();
   }
 
   @Bean

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

@@ -30,7 +30,7 @@
  */
 @ConfigurationProperties("spring.cloud.gcp.firestore")
 public class GcpFirestoreProperties implements CredentialsSupplier {
-  private static final String ROOT_PATH_FORMAT = "projects/%s/databases/(default)/documents";
+  private static final String ROOT_PATH_FORMAT = "projects/%s/databases/%s/documents";
 
   /**
    * Overrides the GCP OAuth2 credentials specified in the Core module. Uses same URL as Datastore
@@ -40,6 +40,8 @@ public class GcpFirestoreProperties implements CredentialsSupplier {
 
   private String projectId;
 
+  private String databaseId;
+
   /**
    * The host and port of the Firestore emulator service; can be overridden to specify an emulator.
    */
@@ -65,6 +67,14 @@ public void setProjectId(String projectId) {
     this.projectId = projectId;
   }
 
+  public String getDatabaseId() {
+    return databaseId;
+  }
+
+  public void setDatabaseId(String databaseId) {
+    this.databaseId = databaseId;
+  }
+
   public String getHostPort() {
     return hostPort;
   }
@@ -82,7 +92,8 @@ public void setEmulator(FirestoreEmulatorProperties emulator) {
   }
 
   public String getFirestoreRootPath(GcpProjectIdProvider projectIdProvider) {
-    return String.format(ROOT_PATH_FORMAT, this.getResolvedProjectId(projectIdProvider));
+    return String.format(ROOT_PATH_FORMAT, this.getResolvedProjectId(projectIdProvider),
+        this.getDatabaseId() == null ? "(default)" : this.getDatabaseId());
   }
 
   public static class FirestoreEmulatorProperties {

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

@@ -55,11 +55,12 @@ class GcpFirestoreAutoConfigurationTests {
           .withPropertyValues("spring.cloud.gcp.firestore.project-id=test-project");
 
   @Test
-  void testDatastoreOptionsCorrectlySet() {
+  void testFirestoreOptionsCorrectlySet() {
     this.contextRunner.run(
         context -> {
           FirestoreOptions datastoreOptions = context.getBean(Firestore.class).getOptions();
           assertThat(datastoreOptions.getProjectId()).isEqualTo("test-project");
+          assertThat(datastoreOptions.getDatabaseId()).isEqualTo("(default)");
         });
   }
 
@@ -95,6 +96,20 @@ void testTransactionManagerExcludedWithoutAutoConfiguration() {
             });
   }
 
+  @Test
+  void testDatabaseId() {
+    contextRunner
+        .withPropertyValues("spring.cloud.gcp.firestore.database-id=mydb")
+        .run(
+            context -> {
+              FirestoreOptions datastoreOptions = context.getBean(Firestore.class).getOptions();
+              assertThat(datastoreOptions.getDatabaseId()).isEqualTo("mydb");
+              String rootPath = context.getBean(GcpFirestoreProperties.class)
+                  .getFirestoreRootPath(() -> "test");
+              assertThat(rootPath).isEqualTo("projects/test/databases/mydb/documents");
+            });
+  }
+
   /** Spring Boot config for tests. */
   @AutoConfigurationPackage
   static class TestConfiguration {

spring-cloud-gcp-data-firestore/src/test/java/com/google/cloud/spring/data/firestore/repository/query/FirestoreRepositoryTests.java

@@ -113,8 +113,6 @@ void testSortQuery_methodName_sortByDocumentId() {
   @Configuration
   @EnableReactiveFirestoreRepositories(basePackageClasses = UserRepository.class)
   static class FirestoreRepositoryTestsConfiguration {
-    private static final String DEFAULT_PARENT =
-        "projects/my-project/databases/(default)/documents";
 
     @Bean
     public FirestoreMappingContext firestoreMappingContext() {