feat: add support for multiple databases

apis/Google.Cloud.Firestore/Google.Cloud.Firestore.IntegrationTests/FirestoreMultipleDbTest.cs

@@ -0,0 +1,75 @@
+// Copyright 2022, Google LLC
+//
+// 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.
+
+using Google.Cloud.ClientTesting;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Google.Cloud.Firestore.IntegrationTests;
+
+[Collection(nameof(MultipleFirestoreDbFixture))]
+public class FirestoreMultipleDbTest
+{
+    private readonly MultipleFirestoreDbFixture _fixture;
+    public FirestoreMultipleDbTest(MultipleFirestoreDbFixture multipleFirestoreDbFixture) =>
+        _fixture = multipleFirestoreDbFixture;
+
+    [Fact]
+    public async Task MultipleDbReadWriteTest()
+    {
+        string dbIdPrefix = IdGenerator.FromGuid(prefix: "db", separator: "-");
+        string correctDbId = $"{dbIdPrefix}-correct";
+        string incorrectDbId = $"{dbIdPrefix}-incorrect";
+        string databaseLocationId = "us-east1";
+        string databaseType = "FIRESTORE_NATIVE";
+
+        // Create two databases one for reading and writing, one for reading to validate that correct database should be referenced.
+        await _fixture.CreateDatabaseAsync(correctDbId, databaseLocationId, databaseType);
+        await _fixture.CreateDatabaseAsync(incorrectDbId, databaseLocationId, databaseType);
+
+        // Write data to the first database; referenced as correct database.
+        FirestoreDb correctDbWriter = new FirestoreDbBuilder
+        {
+            DatabaseId = correctDbId,
+            ProjectId = _fixture.ProjectId
+        }.Build();
+        await correctDbWriter.Collection("cities").Document("SF").SetAsync(new Dictionary<string, object>
+        {
+            { "Name", "San Francisco" },
+            { "State", "CA" },
+            { "Country", "USA" },
+            { "Capital", false },
+            { "Population", 860000 }
+        });
+
+        // Read data from database that was referenced while writing.
+        FirestoreDb correctDbReader = new FirestoreDbBuilder
+        {
+            DatabaseId = correctDbId,
+            ProjectId = _fixture.ProjectId
+        }.Build();
+        DocumentReference readerDocRef = correctDbReader.Collection("cities").Document("SF");
+        DocumentSnapshot correctDbSnapshot = await readerDocRef.GetSnapshotAsync();
+        Dictionary<string, object> items = correctDbSnapshot.ToDictionary();
+        Assert.True(correctDbSnapshot.Exists);
+        Assert.Equal(5, items.Count);
+
+        // Try to read data from random incorrect database, to validate that the snapshot and data do not exist.
+        FirestoreDb incorrectDbReader = new FirestoreDbBuilder { DatabaseId = incorrectDbId, ProjectId = _fixture.ProjectId }.Build();
+        DocumentReference incorrectDbDocRef = incorrectDbReader.Collection("cities").Document("SF");
+        DocumentSnapshot incorrectDbSnapshot = await incorrectDbDocRef.GetSnapshotAsync();
+        Assert.False(incorrectDbSnapshot.Exists);
+    }
+}

apis/Google.Cloud.Firestore/Google.Cloud.Firestore.IntegrationTests/MultipleFirestoreDbFixture.cs

@@ -0,0 +1,59 @@
+// Copyright 2022, Google Inc. All rights reserved.
+//
+// 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
+//
+//     http://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.
+
+using Google.Apis.Auth.OAuth2;
+using Google.Apis.Http;
+using Google.Cloud.ClientTesting;
+using Newtonsoft.Json;
+using System;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Google.Cloud.Firestore.IntegrationTests;
+
+[CollectionDefinition(nameof(MultipleFirestoreDbFixture))]
+public class MultipleFirestoreDbFixture : CloudProjectFixtureBase, ICollectionFixture<MultipleFirestoreDbFixture>
+{
+    private const string RestApiUrlBase = "https://firestore.googleapis.com/v1";
+    private const string ProjectEnvironmentVariable = "FIRESTORE_TEST_PROJECT";
+    private readonly HttpClient _httpClient;
+
+    public MultipleFirestoreDbFixture() : base(ProjectEnvironmentVariable)
+    { 
+        // Scope used for the REST API to create databases.
+        string scope = "https://www.googleapis.com/auth/datastore";
+        string credentialsPath = Environment.GetEnvironmentVariable("GOOGLE_APPLICATION_CREDENTIALS");
+
+        // Initalize gcloud credentials to be used with REST API calls. 
+        GoogleCredential googleCredential = GoogleCredential.FromFile(credentialsPath).CreateScoped(scope);
+        _httpClient = new HttpClientFactory()
+            .CreateHttpClient(new CreateHttpClientArgs { Initializers = { googleCredential } });
+    }
+
+    // TODO: Use Google.Cloud.Firestore.Admin.V1 when that supports this operation.
+
+    /// <summary>
+    /// Creates a new Firestore database using the REST API.
+    /// </summary>
+    public async Task CreateDatabaseAsync(string databaseId, string locationId, string databaseType)
+    {
+        var createDatabaseEndpoint = new Uri($"{RestApiUrlBase}/projects/{ProjectId}/databases?database_id={databaseId}");
+        var data = new { locationId = locationId, type = databaseType };
+        var httpData = new StringContent(JsonConvert.SerializeObject(data), Encoding.UTF8, "application/json");
+        var response = await _httpClient.PostAsync(createDatabaseEndpoint, httpData);
+        response.EnsureSuccessStatusCode();
+    }
+}

apis/Google.Cloud.Firestore/Google.Cloud.Firestore.Tests/FirestoreDbBuilderTest.cs

@@ -19,48 +19,73 @@
 using System;
 using Xunit;
 
-namespace Google.Cloud.Firestore.Tests
+namespace Google.Cloud.Firestore.Tests;
+
+public class FirestoreDbBuilderTest
 {
-    public class FirestoreDbBuilderTest
+    [Fact]
+    public void MaximalConfiguration()
+    {
+        string warning = null;
+        var builder = new FirestoreDbBuilder
+        {
+            ProjectId = "proj",
+            DatabaseId = "db",
+            CallInvoker = new FakeCallInvoker(),
+            WarningLogger = text => warning = text,
+            Settings = new FirestoreSettings { Clock = new FakeClock() },
+            ConverterRegistry = new ConverterRegistry { new SerializationTestData.GuidConverter() }
+        };
+        var db = builder.Build();
+        Assert.Equal("proj", db.ProjectId);
+        Assert.Equal("db", db.DatabaseId);
+        db.LogWarning("Test warning");
+        Assert.Equal("Test warning", warning);
+        Assert.IsType<FakeClock>(db.Client.Settings.Clock);
+        Assert.IsType<CustomConverter<Guid>>(db.SerializationContext.GetConverter(typeof(Guid)));
+    }
+
+    [Fact]
+    public void DefaultDatabase()
     {
-        [Fact]
-        public void MaximalConfiguration()
+        string projectId = "testProjectId";
+        FirestoreDb defaultDb = new FirestoreDbBuilder
         {
-            string warning = null;
-            var builder = new FirestoreDbBuilder
-            {
-                ProjectId = "proj",
-                DatabaseId = "db",
-                CallInvoker = new FakeCallInvoker(),
-                WarningLogger = text => warning = text,
-                Settings = new FirestoreSettings { Clock = new FakeClock() },
-                ConverterRegistry = new ConverterRegistry { new SerializationTestData.GuidConverter() }
-            };
-            var db = builder.Build();
-            Assert.Equal("proj", db.ProjectId);
-            Assert.Equal("db", db.DatabaseId);
-            db.LogWarning("Test warning");
-            Assert.Equal("Test warning", warning);
-            Assert.IsType<FakeClock>(db.Client.Settings.Clock);
-            Assert.IsType<CustomConverter<Guid>>(db.SerializationContext.GetConverter(typeof(Guid)));
-        }
+            ProjectId = projectId,
+            CallInvoker = new FakeCallInvoker()
+        }.Build();
+        Assert.Equal("(default)", defaultDb.DatabaseId);
+    }
 
-        private class FakeCallInvoker : CallInvoker
+    [Fact]
+    public void NonDefaultDatabase()
+    {
+        string databaseId = "testDatabase";
+        string projectId = "testProjectId";
+        FirestoreDb nonDefaultDb = new FirestoreDbBuilder
         {
-            public override AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options) =>
-                throw new NotImplementedException();
+            ProjectId = projectId,
+            DatabaseId = databaseId,
+            CallInvoker = new FakeCallInvoker()
+        }.Build();
+        Assert.Equal(databaseId, nonDefaultDb.DatabaseId);
+    }
+
+    private class FakeCallInvoker : CallInvoker
+    {
+        public override AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options) =>
+            throw new NotImplementedException();
 
-            public override AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options) =>
-                throw new NotImplementedException();
+        public override AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options) =>
+            throw new NotImplementedException();
 
-            public override AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request) =>
-                throw new NotImplementedException();
+        public override AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request) =>
+            throw new NotImplementedException();
 
-            public override AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request) =>
-                throw new NotImplementedException();
+        public override AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request) =>
+            throw new NotImplementedException();
 
-            public override TResponse BlockingUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request) =>
-                throw new NotImplementedException();
-        }
+        public override TResponse BlockingUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request) =>
+            throw new NotImplementedException();
     }
 }

apis/Google.Cloud.Firestore/Google.Cloud.Firestore/FirestoreDb.cs

@@ -1,4 +1,4 @@
-// Copyright 2017, Google Inc. All rights reserved.
+// Copyright 2017, Google Inc. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -43,11 +43,10 @@ public sealed class FirestoreDb
         /// </summary>
         public string ProjectId { get; }
 
-        // Note: currently internal as only the default database ID is supported.
         /// <summary>
-        /// The database ID associated with this database.
+        /// The database ID associated with this database.The value will be "(default)" for the project-default database.
         /// </summary>
-        internal string DatabaseId { get; }
+        public string DatabaseId { get; }
 
         /// <summary>
         /// The resource name of the database, in the form "projects/{project_id}/databases/{database_id}".

apis/Google.Cloud.Firestore/Google.Cloud.Firestore/FirestoreDbBuilder.cs

@@ -50,11 +50,10 @@ public FirestoreDbBuilder() : base(FirestoreClient.ServiceMetadata)
         /// </summary>
         public string ProjectId { get; set; }
 
-        // Note: currently internal as only the default database is supported.
         /// <summary>
         /// The ID of the database within the project. May be null, in which case the default database will be used.
         /// </summary>
-        internal string DatabaseId { get; set; }
+        public string DatabaseId { get; set; }
 
         /// <summary>
         /// Action to receive warning messages. May be null, in which case warnings will be ignored.