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Descriptor API (/api/descriptors) v3.7.0 ​

Load protobuf descriptors (google.protobuf.FileDescriptorSet) into a running GripMock instance without restart.

Endpoint contract ​

  • Method: POST
  • Path: /api/descriptors
  • Header: Content-Type: application/octet-stream
  • Body: binary descriptor set (.pb)

Request example:

bash
curl -X POST http://localhost:4771/api/descriptors \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@service.pb"

Success response (200 OK):

json
{
  "message": "ok",
  "serviceIDs": ["unitconverter.v1.UnitConversionService"],
  "time": "2026-02-17T22:33:17.162507+03:00"
}

Field notes:

  • message: ok when descriptor loading succeeds
  • serviceIDs: fully-qualified service names found in the descriptor
  • time: server timestamp (dynamic)

Common error (400 Bad Request):

json
{"error":"invalid FileDescriptorSet: proto: cannot parse invalid wire-format data"}

This usually means the uploaded file is not a valid FileDescriptorSet.

Validated workflow (unitconverter) ​

This flow was re-checked on the Homebrew release binary (gripmock v3.7.0).

1) Start server ​

bash
gripmock

If you run from this repository source:

bash
go run main.go

2) Move to example project ​

bash
cd examples/projects/unitconverter

3) Load descriptor ​

bash
curl -X POST http://localhost:4771/api/descriptors \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@service.pb"

Expected: message=ok, and serviceIDs includes unitconverter.v1.UnitConversionService.

4) Load stub ​

bash
curl -X POST http://localhost:4771/api/stubs \
  -H "Content-Type: application/json" \
  --data-binary "@convert_weight/stub_single.json"

Expected: JSON array with one UUID (stub ID).

5) Execute test ​

bash
grpctestify convert_weight/case_success.gctf

Expected: 1 passed.

Building service.pb ​

/api/descriptors accepts descriptor sets only.

With protoc:

bash
protoc \
  -I . \
  --include_imports \
  --descriptor_set_out=service.pb \
  service.proto

With buf:

bash
buf build -o service.pb

Transport details ​

  • Use --data-binary, not -d, for binary uploads
  • If localhost is not reachable in your environment, use 127.0.0.1
  • If HTTP proxy variables interfere with local calls, use:
bash
curl --noproxy '*' -X POST http://localhost:4771/api/descriptors \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@service.pb"

Troubleshooting ​

invalid FileDescriptorSet:

  • rebuild descriptor as FileDescriptorSet
  • with protoc, keep --include_imports when imports exist

Test path does not exist in grpctestify:

  • run from examples/projects/unitconverter

Service not found during tests:

  • load descriptors first, then stubs, then run tests

Quick sanity check for admin API reachability:

bash
curl -s http://localhost:4771/api/stubs