Request body missing in Rails app behind Envoy Gateway – Possible Envoy config issue?

[mohammed-rahib]

I'm using Envoy Gateway in my EKS cluster, and I'm facing an issue where the request body is missing in our Rails app when receiving webhooks from a third-party client.

Setup:
I have a custom EnvoyProxy resource.

My GatewayClass points to this EnvoyProxy.

A Gateway is defined using that class.

I have a Service and an HTTPRoute routing traffic to a Rails application pod.

The third-party service is sending webhook POST requests, and they claim that the request body is being sent properly. However, when it reaches our Rails app, the body is empty.
NB:- When we replicated their request using curl, the body was received correctly.

My questions:
Could this be a misconfiguration in Envoy Gateway that strips or drops the request body?

Is there a way to log the request body in the Envoy Proxy pod logs to verify if the body is received at the proxy level?

Right now, I'm seeing only the default Envoy access logs, as shown here:
https://gateway.envoyproxy.io/latest/tasks/observability/proxy-accesslog/#default-access-log

Any guidance on:

Possible misconfigurations to check?

How to enable full request/response body logging (even temporarily for debugging)?

[zirain]

you can check with %BYTES_RECEIVED%.

[mohammed-rahib]

thanks @zirain
I’m seeing non-zero values for bytes_received, but the numbers are quite small,typically around 115, 177, 92, etc. Could it be that this field includes the size of the headers, and what I'm observing is mostly header data rather than the request body? And again, is there a way to log both the request headers and body for further inspection?

[zirain]

you can check header with %REQUEST_HEADERS_BYTES%.

[mohammed-rahib]

hello @zirain
Could you guide me on how to log the request body? I've tried several times using EnvoyExtensionPolicy with an inline Lua script—using help from ChatGP,but I haven't been able to get it to work correctly.