Generate gRPC API using buf

* APIs are described in `/proto` using buf.build.
* Generated code is stored under `a3m/api`.
* Genearted docs can be found at https://buf.build/artefactual/a3m.
* It includes a couple of CI workflows to validate PRs and push to the BSR.

.github/workflows/buf-pull-request.yml

@@ -0,0 +1,15 @@
+name: Buf (pull request)
+on: pull_request
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: bufbuild/buf-setup-action@v1
+    - uses: bufbuild/buf-lint-action@v1
+      with:
+        input: proto
+    # - uses: bufbuild/buf-breaking-action@v1
+    #   with:
+    #     input: proto
+    #     against: 'https://github.com/${GITHUB_REPOSITORY}.git#branch=main'

.github/workflows/buf-push.yml

@@ -0,0 +1,22 @@
+name: Buf (push)
+on:
+  push:
+    branches:
+    - main
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: bufbuild/buf-setup-action@v1
+    - uses: bufbuild/buf-lint-action@v1
+      with:
+        input: proto
+    # - uses: bufbuild/buf-breaking-action@v1
+    #   with:
+    #     input: proto
+    #     against: 'https://github.com/${GITHUB_REPOSITORY}.git#branch=main'
+    - uses: bufbuild/buf-push-action@v1
+      with:
+        input: proto
+        buf_token: ${{ secrets.BUF_TOKEN }}

Makefile

@@ -134,16 +134,13 @@ amflow:  ## Display the workflow in amflow.
 		artefactual/amflow:latest \
 			edit --file=/workflow.json
 
-.PHONY: protoc
-protoc:  ## Generate gRPC code.
-	$(call compose_run, \
-		--entrypoint python \
-		a3m \
-			-m grpc_tools.protoc -I=. --python_out=. --grpc_python_out=. a3m/server/rpc/proto/a3m.proto)
-	$(call compose_run, \
-		--entrypoint black \
-		a3m \
-			a3m/server/rpc/proto)
+.PHONY: buf
+buf:
+	docker run \
+		--volume "$(CURDIR)/proto:/workspace" \
+		--workdir /workspace \
+		bufbuild/buf:1.4.0 \
+			$(ARG)
 
 .PHONY: help
 help:  ## Print this help message.

a3m/api/transferservice/v1beta1/__init__.py

@@ -0,0 +1,12 @@
+from . import request_response_pb2
+from . import request_response_pb2_grpc
+from . import service_pb2
+from . import service_pb2_grpc
+
+
+__all__ = [
+    "request_response_pb2_grpc",
+    "request_response_pb2",
+    "service_pb2_grpc",
+    "service_pb2",
+]