Missing Content-Type Field

[callensm]

Bug Report

Version

[dependencies]
prost = "0.6"
tonic = "0.3"
tonic-health = "0.2"

[build-dependencies]
tonic-build = "0.3"

Platform

Darwin MacBook Pro 19.5.0 Darwin Kernel Version 19.5.0

Description

I'm using the tonic_health service and a lightweight gRPC service and the servers are standing up fine and when I make a call to it with grpcurl, the protocol responds back with the appropriate message.

However, when I try to tie the server into an ecosystem that utilizes it and the health service, I keep getting:

* rpc error: code = Unknown desc = OK: HTTP status code 200; transport: missing content-type field

I've tried manually appending the content-type field to the response metadata as both application/grpc and application/grpc+proto as:

let mut res = Response::new(msg);
res.metadata_mut().append(
  "content-type",
  metadata::MetadataValue::from_str("application/grpc").unwrap(),
);
Ok(res)

but this still doesn't resolve the issue.

[LucioFranco]

Tonic should always be setting the content field. Do you know if this is an issue with just tonic-health or is it other tonic endpoints as well?

[edrevo]

@callensm, could you explain why you closed the issue? i'm also seeing a code = Unknown desc = OK: HTTP status code 200; transport: missing content-type field error when using a tonic server