For… reasons, I wanted to pre-filter gRPC requests to check for authorization. Authorization is implemented as a ‘micro-service’ and I wanted the authorization server to run in the same process as the gRPC client.

TL;DR:

• Shiju’s “Writing gRPC Interceptors in Go” is great
• This Stack overflow answer ostensibly for writing unit tests for gRPC got me an in-process server

What follows stands on these folks’ shoulders…

A key motivator for me to write blog posts is that helps me ensure that I understand things. Writing this post, I realized I’d not researched gRPC Interceptors and, as luck would have it, I found some interesting content, not on grpc.io but on the grpc-ecosystem repo, specifically Go gRPC middleware. But, I refer again to Shiju’s clear and helpful “Writing gRPC Interceptors in Go”