Can StackExchange.Redis connection without port work in Docker bridge network?

[william19821101]

I am developing an ASP.NET Core project and using StackExchange.Redis to connect to a Redis instance running in a Docker container. My .NET project is also running in a Docker container, and both containers are in the same Docker bridge network.

The Redis container is named "redis", so this way works => ConnectionMultiplexer.Connect("redis:6379,abortConnect=false,password=xxx")

However, if I remove the port from the connection string, it doesn't work => ConnectionMultiplexer.Connect('redis,abortConnect=false,password=xxx'). I receive the message: "The specified endpoint is not defined (Parameter 'endpoint')"

I'm aware that we can use container name as a host to connect without specifying the port in the same Docker bridge network. But is it necessary to include the port in the StackExchange.Redis connection?

[mgravell]

I'm intrigued - those two things should be functionally identical... I'll see what I can find.

[mgravell]

With a local hosts entry for redis, this works fine:

using StackExchange.Redis;

using var muxer = ConnectionMultiplexer.Connect("redis,abortConnect=false,password=xxx");
var ttl = await muxer.GetDatabase().PingAsync();
Console.WriteLine($"connected; ttl={ttl.TotalMilliseconds}ms");

with output:

connected; ttl=0.6956ms

Do you have a runnable repro? I'm not seeing any failure here. Also: what library version are you using? Finally, is there a stack trace on that message, so we can see where it is originating?

[mgravell]

I think what you're actually doing is this:

var server = muxer.GetServer("redis");

Now, that parameter is called hostAndPort, and that: currently requires the port. I think the real question here is:

Can GetServer(string) apply the same default port logic that Connect uses when parsing endpoints referred only as a host?

That's not a terrible idea, but today: it doesn't do that.

Workaround for today:

var server = muxer.GetServer(muxer.GetEndPoints().Single());

or

var server = muxer.GetServers().Single();

[mgravell]

So: I did a spike, and the changes needed to do this aren't huge, but: it adds complexity. The only scenario I can think of when people don't want to be really precise with their endpoints is: single endpoint - and in that scenario, the two approaches shown above already give a simple solution. They're also more efficient, I think - as to do this the magic way would require two sets of endpoint allocation.

IMO: leave it alone.

Before I conclude that, have I correctly interpreted the scenario, and do the workarounds shown above work?

[william19821101]

Hi Marc,
Thank you for correcting my question accurately. Yes, I did what you thought I hadn't mentioned in my post, and that seems to be the point.
var server = muxer.GetServer("redis");

And I've tried your solution that perfectly meets my needs.