generate openapi.json with fastapi

sample_openapi_spec.py

"""python scripts/sample_openapi_spec.py openapi.json title version"""
import json
import sys

import fastapi
from fastapi import Body
from fastapi import Depends
from fastapi import Query
from fastapi.openapi.utils import get_openapi
from fastapi.security import APIKeyHeader
from pydantic import BaseModel

app = fastapi.FastAPI()

# user write api definition here
# define security
security = APIKeyHeader(name='api_key', scheme_name='api_key')
security2 = APIKeyHeader(name='token', scheme_name='token')


# define api
@app.get('/health')
def health(a: int = Query(..., description='a'),
           token: str = Depends(security2)):
  """check health"""
  pass


class Health(BaseModel):
  power: str = 'on'


@app.post('/health')
def health(a: int = Query(..., description='a'),
           data: Health = Body(..., description='health data'),
           token: str = Depends(security)):
  """modify health"""
  pass


# define server
server = [{"url": "http://localhost:8000"}]
# end


def check_duplicated_operation_id(schema):
  operation_ids = [
      api['operationId'] for path in schema['paths'].values()
      for api in path.values()
  ]
  duplicated = set(a for a in operation_ids if operation_ids.count(a) > 1)
  if len(duplicated) > 0:
    raise ValueError(f'found duplicated operation ids: {duplicated}')


openapi_schema = get_openapi(
    title=sys.argv[2],
    version=sys.argv[3],
    routes=app.routes,
    servers=server,
)
check_duplicated_operation_id(openapi_schema)

with open(sys.argv[1], 'w') as f:
  json.dump(openapi_schema, f, indent=2, ensure_ascii=False)