Poem GRPC does not work behind traefik proxy when compression middleware is enabled

[tgcGlaDius]

Expected Behavior

GRPC requests are properly router and responded to when sending requests through a traefik reverse proxy

Actual Behavior

When the poem::middleware::Compression middleware is enabled on the GRPC router and the service is behind a traefik reverse proxy the HTTP2 trailers do not arrive at the GRPC client and the client errors.

This problem has not appeared when running without the reverse proxy

Steps to Reproduce the Problem

1. create a GRPC service (for example the helloworld example) and attach the compression middleware using .with(poem::middleware::Compression::new())
2. setup a traefik reverse proxy using h2c://{ip}:{port} as the service backend as specified in the traefik GRPC example
3. send a GRPC request through the traefik reverse proxy
   • this should error or hang infinetly, depending on the client
4. send a GRPC request directly to the GRPC service
   • this should work without error

Specifications

• Version: poem-grpc 0.4.3, poem 3.0.4

[sunli829]

Content-Encoding cannot be used for GRPC. There is a special protocol in GRPC for compression support. Poem does not support it yet, but I will add it as soon as possible.

https://grpc.io/docs/guides/compression/