Federation Gateway not work properly behind reverse proxy

[fahmifan]

I am testing mercurius as federation gateway, everything works correctly until i try to put it behind a proxy using caddy server.

This is my Caddyfile

:3000 {
    reverse_proxy 127.0.0.1:8100
    tls internal
}

This is the error i got

{
	"statusCode": 500,
	"code": "FST_ERR_BAD_STATUS_CODE",
	"error": "Internal Server Error",
	"message": "Called reply with an invalid status code: undefined"
}

{
  errors: [
    Error: Symbol(FEDERATED_ERROR)
        at Object.sendRequest (LOCAL_PATH/node_modules/mercurius/lib/gateway/request.js:96:13)
        at processTicksAndRejections (internal/process/task_queues.js:93:5)
        at async LOCAL_PATH/node_modules/mercurius/lib/gateway/make-resolver.js:498:24
        at async Object.fastifyGraphQl [as graphql] (LOCAL_PATH/node_modules/mercurius/index.js:627:23) {
      path: [Array],
      locations: [Array],
      extensions: [Object]
    }
  ],
  data: null
}
TypeError: Cannot read property 'data' of undefined
    at maybeFormatErrors (LOCAL_PATH/node_modules/mercurius/index.js:644:39)
    at Object.fastifyGraphQl [as graphql] (LOCAL_PATH/node_modules/mercurius/index.js:636:12)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)

Caddy Version: v2.4.6 node dependencies

{
    "fastify": "^3.27.1",
    "graphql": "^16.3.0",
    "mercurius": "^9.3.2"
}

[fahmifan]

So i clone the mercurius master to do some debug. And found the cause, it was this code, ~~this request never reached the federated service when the original request comes from caddy proxy~~ the response is not a json

The SDL query was ok

I also try upgrade the udici version to latest ^4.14.1 but, still the same

[fahmifan]

So the issue is the federated service return response in gzip, but the mercurius gateway can't handle it if the request comes from reverse proxy

[mcollina]

We are not passing an Accept-Encoding header and it seems your server is always applying gzip encoding.

Could you try a quick fix passing Content-Encoding: identity via initHeaders and rewriteHeaders.

It might also be that we need a fix somewhere to handle this. Could you write an example to reproduce this with Node.js?

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding

[fahmifan]

We are not passing an Accept-Encoding header and it seems your server is always applying gzip encoding.

Could you try a quick fix passing Content-Encoding: identity via initHeaders and rewriteHeaders.

It might also be that we need a fix somewhere to handle this. Could you write an example to reproduce this with Node.js?

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding

The federated service is written in Go and unfortunately I am unable to replicate it outside the project. But my team decided to disable compression from the federated service.

[simoneb]

@fahmifan is this issue solved?

[fahmifan]

@simoneb well, yeah we resolved it by remove the gzip compression from the federated service. And we enable gzip only in the Load balancer

[simoneb]

I'm going to close this issue then