No way to ignore gun_tunnel_up

[voluntas]

I use Gun as a mechanism to send webhooks, and I write code like #{tunnel => ProxyStreamRef} in the gun:post options to support HTTP Proxy.

My current problem is that the process that calls this post always sends {gun_tunnel_up, ConnPid, StreamRef, Protocol}.

There is no workaround for this, and I need to write code in the handle_info of the gen_server that calls the post to ignore {gun_tunnel_up, ConnPid, StreamRef, Protocol}}.

Is there any better way to get around this?

[essen]

You shouldn't ignore it, it's there to inform you the tunnel is up and that you can send requests. It's sent after you call gun:connect or when the SOCKS connection is established. Until you receive this message, any request you send may not end up on the right server, especially when you use gun:connect. For example:

• Call gun:connect
• Call gun:get with the tunnel option
• Receive a 500 response from gun:connect
• The gun:get that was already sent will not reach the remote endpoint but will instead be handled by the proxy as if it was a normal pipeline request
• Confusion

You should treat gun_tunnel_up the same way as gun_up in your gen_server: it is not ready to do requests until it receives it.

[voluntas]

@essen Ah, thank you for your politeness. I noticed it from the replies I received.

Maybe after calling gun:connect/2, I need to wait for {up, Protocol} = gun:await/2.

I had missed this completely.
https://github.com/ninenines/gun/blob/master/src/gun.erl#L757-L758

Thanks again for your quick replies.

[essen]

If you are using gun:await then you may need to call it multiple times if you connect through proxies: it handles both the gun_up and the gun_tunnel_up messages. When using gun:connect you can mirror what you do with gun:open and call gun:await right after. If you connect through multiple proxies you can call it after every gun:connect. If you were using SOCKS in gun:open then you can call it twice in a raw, once for the SOCKS connection and once for the proxied connection.

Glad that the proxy work is being used, enjoy!

[voluntas]

Thank you very much for the detailed explanation. We are not using SOCKS at this time.

And I should have read the test code properly.
https://github.com/ninenines/gun/blob/master/test/tunnel_SUITE.erl#L881-L894

I was getting it to work without waiting for {up, Protocol} on gun:await/2, but I can't catch it in case of an error.

Thanks again.

P.S.: The Proxy feature of Gun is working great since HTTP Proxy is often used in Japanese companies.