Cannot get proxy to work with Tesla adapter

[glappen]

Hello,

I am trying out this plug, and ran into a strange issue. Configuring tesla_client option was also kind of tricky, and I don't know if I have it setup correctly. The problem I see is that when configured with Tesla (using either mint or hackney as tesla_client), the requests just hang and never complete. Using hackney directly instead of tesla seems to work.

Here's how I have it setup:

mix.exs:

defp deps do
  [
    {:reverse_proxy_plug, "~> 2.1"},
    {:tesla, "~> 1.4"},
    {:mint, "~> 1.4"},
    {:castore, "~> 0.1"}
  ]
end

endpoint.ex:

defmodule MiddleMan.Endpoint do
  use Plug.Router

  plug(Plug.Telemetry, event_prefix: [:middle_man, :plug])
  plug(Plug.Logger)
  plug(:match)

  plug(:dispatch)

  get "/hello" do
    send_resp(conn, 200, "world")
  end

forward("/test",
    to: ReverseProxyPlug,
    client: ReverseProxyPlug.HTTPClient.Adapters.Tesla,
    upstream: "//localhost:8000/",
    client_options: [
      tesla_client: Tesla.client([], {Tesla.Adapter.Mint, []})
    ]
  )
end

When I make a request to http://localhost:4000/test/test.json, I see this in the logs:
15:21:59.484 [info] GET /test/test.json
and the browser keeps loading and loading with no response.

Any clues what I did wrong above? I was unable to figure out how to pass tesla_client option in config.exs, so I ended up passing the options in the forward call.

Any help would be appreciated.....thanks for your time!

[akasprzok]

I've got the same issue.

[akasprzok]

Looking into the code, there's no handling for response_mode: :stream if using Tesla.

[mwhitworth]

According to elixir-tesla/tesla#271 and the Stream section of the documentation, streaming responses isn't supported.

But the current behaviour isn't ideal - we should fail much earlier than that if we can detect this. I'll see what can be done here.

[mwhitworth]

It now throws an ArgumentError if the adapter and response mode are incompatible.

Point taken about the configuration; I'd like to make a pass at the README.md and provide some more examples too.

[mwhitworth]

Released in v2.4.0