public ServerCallInvoker Get(string serviceName)
{
// find callInvoker first if any (fast path)
ServerCallInvoker callInvoker;
if (_invokers.TryGetValue(serviceName, out callInvoker))
{
return(callInvoker);
}
// no luck (slow path): either no call invoker available or a shutdown is in progress
lock (_lock)
{
// this is double-check lock
if (_invokers.TryGetValue(serviceName, out callInvoker))
{
return(callInvoker);
}
// find a (shared) channel for target if any
var target = _serviceDiscovery.FindServiceEndpoint(serviceName);
Channel channel;
if (!_channels.TryGetValue(target, out channel))
{
channel = new Channel(target, ChannelCredentials.Insecure);
_channels.Add(target, channel);
}
// build a new call invoker + channel
callInvoker = new ServerCallInvoker(channel);
_invokers.TryAdd(serviceName, callInvoker);
return(callInvoker);
}
}
public void Revoke(string serviceName, ServerCallInvoker failedCallInvoker)
{
lock (_lock)
{
// only destroy the call invoker if & only if it is still published (first arrived wins)
ServerCallInvoker callInvoker;
if (!_invokers.TryGetValue(serviceName, out callInvoker) || !ReferenceEquals(callInvoker, failedCallInvoker))
{
return;
}
_invokers.TryRemove(serviceName, out callInvoker);
// shutdown the channel
var failedChannel = failedCallInvoker.Channel;
Channel channel;
if (_channels.TryGetValue(failedChannel.Target, out channel) && ReferenceEquals(channel, failedChannel))
{
_channels.Remove(failedChannel.Target);
_serviceDiscovery.Blacklist(failedChannel.Target);
}
failedChannel.ShutdownAsync();
}
}