Added channel state API
diff --git a/src/csharp/Grpc.Core/Channel.cs b/src/csharp/Grpc.Core/Channel.cs
index 18e6f2f..8a71afa 100644
--- a/src/csharp/Grpc.Core/Channel.cs
+++ b/src/csharp/Grpc.Core/Channel.cs
@@ -37,6 +37,8 @@
using System.Threading.Tasks;
using Grpc.Core.Internal;
+using Grpc.Core.Logging;
+using Grpc.Core.Utils;
namespace Grpc.Core
{
@@ -45,6 +47,8 @@
/// </summary>
public class Channel : IDisposable
{
+ static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Channel>();
+
readonly GrpcEnvironment environment;
readonly ChannelSafeHandle handle;
readonly List<ChannelOption> options;
@@ -53,13 +57,14 @@
/// <summary>
/// Creates a channel that connects to a specific host.
- /// Port will default to 80 for an unsecure channel and to 443 a secure channel.
+ /// Port will default to 80 for an unsecure channel and to 443 for a secure channel.
/// </summary>
- /// <param name="host">The DNS name of IP address of the host.</param>
+ /// <param name="host">The name or IP address of the host.</param>
/// <param name="credentials">Credentials to secure the channel.</param>
/// <param name="options">Channel options.</param>
public Channel(string host, Credentials credentials, IEnumerable<ChannelOption> options = null)
{
+ Preconditions.CheckNotNull(host);
this.environment = GrpcEnvironment.GetInstance();
this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
@@ -82,8 +87,8 @@
/// <summary>
/// Creates a channel that connects to a specific host and port.
/// </summary>
- /// <param name="host">DNS name or IP address</param>
- /// <param name="port">the port</param>
+ /// <param name="host">The name or IP address of the host.</param>
+ /// <param name="port">The port.</param>
/// <param name="credentials">Credentials to secure the channel.</param>
/// <param name="options">Channel options.</param>
public Channel(string host, int port, Credentials credentials, IEnumerable<ChannelOption> options = null) :
@@ -91,6 +96,67 @@
{
}
+ /// <summary>
+ /// Gets current connectivity state of this channel.
+ /// </summary>
+ public ChannelState State
+ {
+ get
+ {
+ return handle.CheckConnectivityState(false);
+ }
+ }
+
+ /// <summary>
+ /// Returned tasks completes once channel state has become different from
+ /// given lastObservedState.
+ /// If deadline is reached or and error occurs, returned task is cancelled.
+ /// </summary>
+ public Task WaitForStateChangedAsync(ChannelState lastObservedState, DateTime? deadline = null)
+ {
+ Preconditions.CheckArgument(lastObservedState != ChannelState.FatalFailure,
+ "FatalFailure is a terminal state. No further state changes can occur.");
+ var tcs = new TaskCompletionSource<object>();
+ var deadlineTimespec = deadline.HasValue ? Timespec.FromDateTime(deadline.Value) : Timespec.InfFuture;
+ var handler = new BatchCompletionDelegate((success, ctx) =>
+ {
+ if (success)
+ {
+ tcs.SetResult(null);
+ }
+ else
+ {
+ tcs.SetCanceled();
+ }
+ });
+ handle.WatchConnectivityState(lastObservedState, deadlineTimespec, environment.CompletionQueue, environment.CompletionRegistry, handler);
+ return tcs.Task;
+ }
+
+ /// <summary>
+ /// Allows explicitly requesting channel to connect without starting an RPC.
+ /// Returned task completes once state Ready was seen. If the deadline is reached,
+ /// or channel enters the FatalFailure state, the task is cancelled.
+ /// There is no need to call this explicitly unless your use case requires that.
+ /// Starting an RPC on a new channel will request connection implicitly.
+ /// </summary>
+ public async Task ConnectAsync(DateTime? deadline = null)
+ {
+ var currentState = handle.CheckConnectivityState(true);
+ while (currentState != ChannelState.Ready)
+ {
+ if (currentState == ChannelState.FatalFailure)
+ {
+ throw new OperationCanceledException("Channel has reached FatalFailure state.");
+ }
+ await WaitForStateChangedAsync(currentState, deadline);
+ currentState = handle.CheckConnectivityState(false);
+ }
+ }
+
+ /// <summary>
+ /// Destroys the underlying channel.
+ /// </summary>
public void Dispose()
{
Dispose(true);