Caddy Grpc configuration for hello world Golang app

dd84ai · February 4, 2025, 3:21pm

{"level":"info","ts":1738682279.9113512,"logger":"http.log.access","msg":"handled request","request":{"remote_ip":"52.47.113.81","remote_port":"48244","client_ip":"52.47.113.81","proto":"HTTP/2.0","method":"PRI","host":"","uri":"*","headers":{}},"bytes_read":0,"user_id":"","duration":0.00007736,"size":0,"status":308,"resp_headers":{"Connection":["close"],"Location":["https://*"],"Content-Type":[],"Server":["Caddy"]}}
{"level":"info","ts":1738682281.069223,"logger":"http.log.access","msg":"handled request","request":{"remote_ip":"52.47.113.81","remote_port":"48256","client_ip":"52.47.113.81","proto":"HTTP/2.0","method":"PRI","host":"","uri":"*","headers":{}},"bytes_read":0,"user_id":"","duration":0.00004484,"size":0,"status":308,"resp_headers":{"Connection":["close"],"Location":["https://*"],"Content-Type":[],"Server":["Caddy"]}}
{"level":"info","ts":1738682282.712738,"logger":"http.log.access","msg":"handled request","request":{"remote_ip":"52.47.113.81","remote_port":"48270","client_ip":"52.47.113.81","proto":"HTTP/2.0","method":"PRI","host":"","uri":"*","headers":{}},"bytes_read":0,"user_id":"","duration":0.00003696,"size":0,"status":308,"resp_headers":{"Server":["Caddy"],"Connection":["close"],"Location":["https://*"],"Content-Type":[]}}
{"level":"info","ts":1738682285.262502,"logger":"http.log.access","msg":"handled request","request":{"remote_ip":"52.47.113.81","remote_port":"48282","client_ip":"52.47.113.81","proto":"HTTP/2.0","method":"PRI","host":"","uri":"*","headers":{}},"bytes_read":0,"user_id":"","duration":0.000074041,"size":0,"status":308,"resp_headers":{"Server":["Caddy"],"Connection":["close"],"Location":["https://*"],"Content-Type":[]}}

the found logs with 308 status code is some kind of a clue

Found related potentially issue but it is not having a solution

according to this issue by default GRPC is not resolving any redirects

github.com/grpc/grpc-java

Set custom metadata with value from response body

opened 06:29AM - 07 Feb 19 UTC

closed 08:16PM - 26 Mar 20 UTC

mayank-dixit

question

*** Question: How do I access `headers.put()` and `responseBody` at one place i…n interceptCall? *** This is what I Intend to do: - Generate image url at `/myapi/user/1/image` This is how I tried: - I generated AWS s3 url (temporary) and tried sending 302 at that url. That was the general practise in HTTP server as well. This is the Blocker: - No such concept as 302 redirect in grpc This is the alternative I thought of: - I'll send my response with 200. But I'll set a custom metadata called `location` with the url present in response body. My [Http proxy server](https://github.com/grpc-ecosystem/grpc-gateway) could check when response metadata has `location` set, respond 302 REDIRECT with metadata value. This is how I tried: - Created custom interceptor that implements `ServerInterceptor` - Overrode `interceptCall` and tried setting body to metadata This is the Blocker: - I'm unable to get hold of `setMetdata()` and `responseBody` at one place together. - sendHeaders is the place where I'm able to set header as shown in [HeaderServerInterceptor](https://github.com/grpc/grpc-java/blob/master/examples/src/main/java/io/grpc/examples/header/HeaderServerInterceptor.java#L48) example. - onMessage is the place where I can access `responseBody`. - Can't find one place where I can do both!

It may be possible with custom Serverinterceptor… but there are no code examples how