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mixing pydantic and single dispatch
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import os | |
from typing import Union | |
from pymongo import MongoClient, ReadPreference | |
import pytest | |
from functools import singledispatch | |
from pydantic import BaseSettings, parse_obj_as | |
from typing_extensions import Literal | |
class LocalContext(BaseSettings): | |
env: Literal["local"] # 1 | |
mongo_url: str | |
class ProdContext(BaseSettings): | |
env: Literal["prod"] # 1 | |
mongo_url: str | |
mongo_replicaset: str # 1 | |
Context = Union[LocalContext, ProdContext] | |
@singledispatch # 2 | |
def read_env(context: Context) -> MongoClient: | |
"""implementations in dispatched functions""" | |
@read_env.register # 3 | |
def create_local_mongo(context: LocalContext) -> MongoClient: | |
print("Creating local MongoClient") | |
return MongoClient(context.mongo_url) # 4 | |
@read_env.register # 3 | |
def create_prod_mongo(context: ProdContext) -> MongoClient: | |
print("Creating production MongoClient") | |
return MongoClient( | |
context.mongo_url, | |
replicaSet=context.mongo_replicaset, | |
read_preference=ReadPreference.NEAREST, | |
) # 4 | |
def test_reads_local_context(): | |
os.environ.clear() | |
os.environ["ENV"] = "local" | |
os.environ["MONGO_URL"] = "mongodb://madeup_name:madeup_pass@localhost:27017" | |
context = parse_obj_as(Context, {}) # 5 | |
client = read_env(context) # 5 | |
assert client.address == ("localhost", 27017) # 6 | |
def test_reads_prod_context(): | |
os.environ.clear() | |
mongo_url = ( | |
"mongodb://madeup_name:[email protected]:27017/?authSource=admin" | |
) | |
os.environ["ENV"] = "prod" | |
os.environ["MONGO_URL"] = mongo_url | |
os.environ["MONGO_REPLICASET"] = "put-your-real-replicaset-here" | |
context = parse_obj_as(Context, {}) # 5 | |
client = read_env(context) # 5 | |
assert client.address == ("mongodb0.example.com", 27017) # 6 |
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