grpc-ecosystem/grpc-gateway

Generating Multiple Path Bindings for Single gRPC Call

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#720 opened on Aug 9, 2018

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enhancementhelp wanted

Description

I have a field in a protobuf message called "parent". It looks like this:

message ListRolesRequest {
    // The resource name of the parent resource in one of the following formats:
    // `` (empty string) -- this refers to curated roles.
    // `organizations/{organization_id}`
    // `tenants/{tenant_id}`
    string parent = 1;
  ...
}

And a gRPC method that looks like this:

rpc ListRoles(ListRolesRequest) returns (ListRolesResponse) {
      option (google.api.http) = {
        get: "/auth/iam/roles"
        additional_bindings {
          get: "/auth/iam/{parent=organizations/*}/roles"
        }
        additional_bindings {
          get: "/auth/iam/{parent=tenants/*}/roles"
        }
      };
}

The parent can take the form organizations/<org_id> or tenants/<tenant_id> or it can be empty. I'd like the generated swagger definitions to match all three. For example:

GET /auth/iam/roles GET /auth/iam/organizations/<org_id>/roles GET /auth/iam/tenants/<tenant_id>/roles

The swagger generator currently only generates two paths:

GET /auth/iam/roles GET /auth/iam/{parent}/roles

{parent} only matches a single path parameter, and since the parent can include a slash you can't get a match.

What's the correct way of doing this?

Contributor guide

Tech stack
gogrpcrest api
Domain
backendapi
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Protobuf message definitiongRPC HTTP annotationgrpc gateway swagger generation
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the swagger generation code in grpc gateway, specifically how `additional bindings` are processed. The issue mentions that only a single path parameter `{parent}` is generated instead of multiple explicit paths. Look at the generator logic in `protoc gen grpc gateway` or the swagger output plugin. Examine comments in the issue for any suggested fixes or pointers. The goal is to make the generator produce separate paths for `organizations/*` and `tenants/*` patterns as defined in the protobuf annotations.