add metadata api

src/Dapr.Client/DaprClient.cs

@@ -1,4 +1,4 @@
-// ------------------------------------------------------------------------
+// ------------------------------------------------------------------------
 // Copyright 2021 The Dapr Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -338,6 +338,36 @@ public HttpRequestMessage CreateInvokeMethodRequest<TRequest>(string appId, stri
         /// <returns>A <see cref="Task" /> that will return when the operation has completed.</returns>
         public abstract Task ShutdownSidecarAsync(CancellationToken cancellationToken = default);
 
+        /// <summary>
+        /// Calls the sidecar's metadata endpoint which returns information including:
+        /// <list type="bullet">
+        /// <item>
+        /// <description>The sidecar's ID.</description>
+        /// </item>
+        /// <item>
+        /// <description>The registered/active actors if any.</description>
+        /// </item>
+        /// <item>
+        /// <description>Registered components including name, type, version, and information on capabilities if present.</description>
+        /// </item>
+        /// <item>
+        /// <description>Any extended metadata that has been set via <see cref="SetMetadataAsync"/></description>
+        /// </item>
+        /// </list>
+        /// </summary>
+        /// <param name="cancellationToken">A <see cref="CancellationToken" /> that can be used to cancel the operation.</param>
+        /// <returns>A <see cref="Task{T}" /> that will return the value when the operation has completed.</returns>
+        public abstract Task<DaprMetadata> GetMetadataAsync(CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// Perform service add extended metadata to the Dapr sidecar.
+        /// </summary>
+        /// <param name="attributeName">Custom attribute name</param>
+        /// <param name="attributeValue">Custom attribute value</param>
+        /// <param name="cancellationToken">A <see cref="CancellationToken" /> that can be used to cancel the operation.</param>
+        /// <returns>A <see cref="Task" /> that will return the value when the operation has completed.</returns>
+        public abstract Task SetMetadataAsync(string attributeName, string attributeValue, CancellationToken cancellationToken = default);
+
         /// <summary>
         /// Perform service invocation using the request provided by <paramref name="request" />. The response will
         /// be returned without performing any validation on the status code.

src/Dapr.Client/DaprClientGrpc.cs

@@ -1367,6 +1367,46 @@ public async override Task ShutdownSidecarAsync(CancellationToken cancellationTo
             await client.ShutdownAsync(new Empty(), CreateCallOptions(null, cancellationToken));
         }
 
+        /// <inheritdoc/>
+        public override async Task<DaprMetadata> GetMetadataAsync(CancellationToken cancellationToken = default)
+        {
+            var options = CreateCallOptions(headers: null, cancellationToken);
+            try
+            {
+                var response = await client.GetMetadataAsync(new Empty(), options);
+                return new DaprMetadata(response.Id,
+                                        response.ActiveActorsCount.Select(c => new DaprActorMetadata(c.Type, c.Count)).ToList(),
+                                        response.ExtendedMetadata.ToDictionary(c => c.Key, c => c.Value),
+                                        response.RegisteredComponents.Select(c => new DaprComponentsMetadata(c.Name, c.Type, c.Version, c.Capabilities.ToArray())).ToList());
+            }
+            catch (RpcException ex)
+            {
+                throw new DaprException("Get metadata operation failed: the Dapr endpoint indicated a failure. See InnerException for details.", ex);
+            }
+        }
+
+        /// <inheritdoc/>
+        public override async Task SetMetadataAsync(string attributeName, string attributeValue, CancellationToken cancellationToken = default)
+        {
+            ArgumentVerifier.ThrowIfNullOrEmpty(attributeName, nameof(attributeName));
+
+            var envelope = new Autogenerated.SetMetadataRequest()
+            {
+                Key = attributeName,
+                Value = attributeValue
+            };
+
+            var options = CreateCallOptions(headers: null, cancellationToken);
+
+            try
+            {
+                _ = await this.Client.SetMetadataAsync(envelope, options);
+            }
+            catch (RpcException ex)
+            {
+                throw new DaprException("Set metadata operation failed: the Dapr endpoint indicated a failure. See InnerException for details.", ex);
+            }
+        }
         #endregion
 
         protected override void Dispose(bool disposing)

src/Dapr.Client/DaprMetadata.cs

@@ -0,0 +1,126 @@
+// ------------------------------------------------------------------------
+// Copyright 2021 The Dapr 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
+//     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 System.Collections.Generic;
+
+namespace Dapr.Client
+{
+    /// <summary>
+    /// Represents a metadata object returned from dapr sidecar.
+    /// </summary>
+    public sealed class DaprMetadata
+    {
+        /// <summary>
+        ///  Initializes a new instance of the <see cref="DaprMetadata"/> class.
+        /// </summary>
+        /// <param name="id">The application id.</param>
+        /// <param name="actors">The registered actors metadata.</param>
+        /// <param name="extended">The list of custom attributes as key-value pairs, where key is the attribute name.</param>
+        /// <param name="components">The loaded  components metadata.</param>
+        public DaprMetadata(string id, IReadOnlyList<DaprActorMetadata> actors, IReadOnlyDictionary<string, string> extended, IReadOnlyList<DaprComponentsMetadata> components)
+        {
+            Id = id;
+            Actors = actors;
+            Extended = extended;
+            Components = components;
+        }
+
+        /// <summary>
+        /// Gets the application id.
+        /// </summary>
+        public string Id { get; }
+
+        /// <summary>
+        /// Gets the registered actors metadata.
+        /// </summary>
+        public IReadOnlyList<DaprActorMetadata> Actors { get; }
+
+        /// <summary>
+        /// Gets the list of custom attributes as key-value pairs, where key is the attribute name.
+        /// </summary>
+        public IReadOnlyDictionary<string, string> Extended { get; }
+
+        /// <summary>
+        ///  Gets the loaded  components metadata.
+        /// </summary>
+        public IReadOnlyList<DaprComponentsMetadata> Components { get; }
+    }
+
+    /// <summary>
+    /// Represents a actor metadata object returned from dapr sidecar.
+    /// </summary>
+    public sealed class DaprActorMetadata
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="DaprActorMetadata"/> class.
+        /// </summary>
+        /// <param name="type">This registered actor type.</param>
+        /// <param name="count">The number of actors running.</param>
+        public DaprActorMetadata(string type, int count)
+        {
+            Type = type;
+            Count = count;
+        }
+
+        /// <summary>
+        /// Gets the registered actor type.
+        /// </summary>
+        public string Type { get; }
+
+        /// <summary>
+        /// Gets the number of actors running.
+        /// </summary>
+        public int Count { get; }
+    }
+
+    /// <summary>
+    /// Represents a components metadata object returned from dapr sidecar.
+    /// </summary>
+    public sealed class DaprComponentsMetadata
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="DaprComponentsMetadata"/> class.
+        /// </summary>
+        /// <param name="name">The name of the component.</param>
+        /// <param name="type">The component type.</param>
+        /// <param name="version">The component version.</param>
+        /// <param name="capabilities">The supported capabilities for this component type and version.</param>
+        public DaprComponentsMetadata(string name, string type, string version, string[] capabilities)
+        {
+            Name = name;
+            Type = type;
+            Version = version;
+            Capabilities = capabilities;
+        }
+
+        /// <summary>
+        /// Gets the name of the component.
+        /// </summary>
+        public string Name { get; }
+
+        /// <summary>
+        /// Gets the component type.
+        /// </summary>
+        public string Type { get; }
+
+        /// <summary>
+        /// Gets the component version.
+        /// </summary>
+        public string Version { get; }
+
+        /// <summary>
+        /// Gets the supported capabilities for this component type and version.
+        /// </summary>
+        public string[] Capabilities { get; }
+    }
+}

test/Dapr.Client.Test/DaprClientTest.InvokeMethodAsync.cs

@@ -1,4 +1,4 @@
-// ------------------------------------------------------------------------
+// ------------------------------------------------------------------------
 // Copyright 2021 The Dapr Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -14,6 +14,7 @@
 namespace Dapr.Client.Test
 {
     using System;
+    using System.Collections.Generic;
     using System.Net;
     using System.Net.Http;
     using System.Net.Http.Json;
@@ -22,6 +23,7 @@ namespace Dapr.Client.Test
     using System.Threading;
     using System.Threading.Tasks;
     using Dapr.Client;
+    using FluentAssertions;
     using Xunit;
 
     // Most of the InvokeMethodAsync functionality on DaprClient is non-abstract methods that