Refactor to use FastAPI (#252)

Dockerfile

@@ -19,7 +19,8 @@ RUN poetry install --only main
 
 EXPOSE 5000
 
-ENV FLASK_APP=api.py
-
-ENTRYPOINT flask run --host 0.0.0.0
-
+CMD ["gunicorn", "api:app", \
+     "--bind", "0.0.0.0:5000", \
+     "--workers", "20", \
+     "--worker-class", "uvicorn.workers.UvicornWorker", \
+     "--timeout", "0"]

Makefile

@@ -10,7 +10,7 @@ start-ajv:
 	npm run start
 
 run: start-ajv
-	poetry run ./scripts/run_app.sh
+	poetry run python api.py
 
 lint: lint-python
 	npm run lint

README.md

@@ -19,6 +19,14 @@ To run the app:
 ```
 make run
 ```
+If you want to run the app locally using multiple server workers set reload to "False" in the Uvicorn settings in api.py:
+```python
+uvicorn.run("api:app", workers=20, port=5001, reload=False)
+```
+The validator can be called directly in the browser using the "/validate" endpoint and the "url" parameter for the address where the schema is located (eg. GitHub Gist raw json):
+```
+http://localhost:5001/validate?url=...
+```
 
 ## Testing
 

api.py

@@ -1,11 +1,92 @@
-from flask import Flask
+import json
+import os
+from json import JSONDecodeError
+from urllib import error, request
 
-from app.views.status import status_blueprint
-from app.views.validate import validate_blueprint
+import requests
+import uvicorn
+from fastapi import Body, FastAPI, Response
+from requests import RequestException
+from structlog import get_logger
+
+from app.validators.questionnaire_validator import QuestionnaireValidator
+
+app = FastAPI()
+
+
+@app.get("/status")
+async def status():
+    return Response(status_code=200)
+
+
+logger = get_logger()
+
+AJV_HOST = os.getenv("AJV_HOST", "localhost")
+
+AJV_VALIDATOR_URL = f"http://{AJV_HOST}:5002/validate"
+
+
+@app.post("/validate")
+async def validate_schema_request_body(payload=Body(None)):
+    logger.info("Validating schema")
+    return await validate_schema(payload)
+
+
+@app.get("/validate")
+async def validate_schema_from_url(url=None):
+    if url:
+        logger.info("Validating schema from URL", url=url)
+        try:
+            with request.urlopen(url) as opened_url:
+                return await validate_schema(data=opened_url.read().decode())
+        except error.URLError:
+            return Response(
+                status_code=404, content=f"Could not load schema at URL [{url}]"
+            )
+
+
+async def validate_schema(data):
+    json_to_validate = None
+    if data:
+        if isinstance(data, str):
+            try:
+                json_to_validate = json.loads(data)
+            except JSONDecodeError:
+                logger.info("Could not parse JSON", status=400)
+                return Response(status_code=400, content="Could not parse JSON")
+        elif isinstance(data, dict):
+            json_to_validate = data
+
+    response = {}
+    try:
+        ajv_response = requests.post(
+            AJV_VALIDATOR_URL, json=json_to_validate, timeout=10
+        )
+        if ajv_response_dict := ajv_response.json():
+            response["errors"] = ajv_response_dict["errors"]
+            logger.info("Schema validator returned errors", status=400)
+            return response, 400
+
+    except RequestException:
+        logger.info("AJV Schema validator service unavailable")
+        return json.dumps(obj={}, error="AJV Schema validator service unavailable")
+
+    validator = QuestionnaireValidator(json_to_validate)
+    validator.validate()
+
+    if validator.errors:
+        response["errors"] = validator.errors
+        logger.info("Questionnaire validator returned errors", status=400)
+        response = Response(content=json.dumps(response), status_code=400)
+
+        return response
+
+    logger.info("Schema validation passed", status=200)
+
+    response = Response(content=json.dumps(response), status_code=200)
+
+    return response
 
-application = Flask(__name__)
-application.register_blueprint(validate_blueprint)
-application.register_blueprint(status_blueprint)
 
 if __name__ == "__main__":
-    application.run(port=5001)
+    uvicorn.run("api:app", workers=20, port=5001, reload=True)

app/validators/value_source_validator.py

@@ -25,7 +25,7 @@ class ValueSourceValidator(Validator):
     }
     RESPONSE_METADATA_IDENTIFIERS = ["started_at"]
 
-    def __init__(
+    def __init__(  # pylint: disable=too-many-positional-arguments
         self,
         value_source,
         json_path,