Extract OAK RPC as a fully standalone service (#371)

### Related issues

- Closes #368 

### Summary

- adds Dockerfile for the OAK RPC service image. It's based on the API
image, but changes the startup script (i.e., to just run the OAK RPC
server, not the Monarch API server) and includes a healthcheck script
for testing the service within the container
- adds a step to the `build-and-deploy-images` GH workflow to build the
new image
- removes launching and waiting on the OAK RPC server to start from the
API's startup script

### Checks

- [ ] All tests have passed (or issues created for failing tests)

.github/workflows/build-and-deploy-images.yaml

@@ -38,6 +38,17 @@ jobs:
           image_tag: latest, ${{ steps.get-tag.outputs.IMAGE_TAG }}, ${{ github.sha }}
           dockerfile: ./backend/Dockerfile
 
+      - name: Build and Push OAK RPC Server Image
+        uses: RafikFarhad/push-to-gcr-github-action@v5-beta
+        with:
+          gcloud_service_key: ${{ secrets.JSON_GCLOUD_SERVICE_ACCOUNT_JSON }}
+          registry: us-central1-docker.pkg.dev
+          project_id: monarch-initiative
+          image_name: monarch-api/monarch-oak-server
+          image_tag: latest, ${{ steps.get-tag.outputs.IMAGE_TAG }}, ${{ github.sha }}
+          dockerfile: ./services/oak_rpc_server/Dockerfile
+          build_args: FROM_IMAGE=monarch-api/monarch-api:${{ github.sha }}
+
   build-and-push-frontend-image:
     runs-on: ubuntu-latest
     defaults:

backend/start_api.sh

@@ -1,11 +1,5 @@
 #!/usr/bin/bash 
 
-# before we start, run the oak server in the background...
-poetry run python -m src.monarch_py.api.oak_server &
-
-# ...but block while we wait for it to start serving request
-./wait-for-it.sh -t 0 ${OAK_SERVER_HOST:-localhost}:${OAK_SERVER_PORT:-18811}
-
 # check for uvicorn workers env var, default to 8
 UVICORN_WORKERS=${UVICORN_WORKERS:-8}
 

services/oak_rpc_server/Dockerfile

@@ -0,0 +1,23 @@
+# This Dockerfile is used to build a supplementary image, based on
+# the Monarch API image, that runs the OAK RPC server.
+# Note that it takes a build argument, FROM_IMAGE, which should be the
+# API image and tag that's associated with the current build.
+# It assumes that the build context is the root of the repository.
+# The image is built using the following command structure:
+#  (from the root of the repository, i.e. .../monarch-app)
+#  docker build \
+#    --build-arg="FROM_IMAGE=<API image:tag>" \
+#    -f services/oak_lib/Dockerfile .
+
+ARG FROM_IMAGE
+FROM ${FROM_IMAGE}
+
+COPY ./services/oak_rpc_server/start_rpc_service.sh /var/oak_server/start_rpc_service.sh
+COPY ./services/oak_rpc_server/rpc_healthcheck.py /var/oak_server/rpc_healthcheck.py
+
+HEALTHCHECK \
+    --interval=30s --timeout=15s --retries=3 \
+    --start-period=120s \
+    CMD poetry run python /var/oak_server/rpc_healthcheck.py || exit 1
+
+CMD /var/oak_server/start_rpc_service.sh

services/oak_rpc_server/rpc_healthcheck.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python
+
+from monarch_py.api.config import OakRPCMarshaller
+
+def main():
+    try:
+        oak = OakRPCMarshaller()
+
+        # run the 'warmup' query from init_semsim()
+        # note, this is roughly equivalent to 
+        # /v3/api/semsim/compare/MP%3A0010771/HP%3A0004325
+        oak.compare( subjects=["MP:0010771"], objects=["HP:0004325"])
+
+    except Exception as ex:
+        print(ex)
+        exit(1)
+
+if __name__ == '__main__':
+    main()

services/oak_rpc_server/start_rpc_service.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+poetry run python -m src.monarch_py.api.oak_server