<@ULVA73B9P> best way of testing api calls for pre...
# ask-marvin
m
@Marvin best way of testing api calls for prefect 3.0
m
Testing API calls in Prefect 3.0 can involve several strategies to ensure that your workflows are reliable, even when interacting with external services. Although the documentation didn't pinpoint specific testing frameworks or libraries, it offered some best practices and insights. 1. Retries on Failure: Prefect provides built-in support for retrying tasks. If your API call fails due to network issues or intermittent server errors, you can configure your flow to automatically retry the request. This can greatly enhance the robustness of your workflows. 2. Handle Rate Limiting: If your API calls are subject to rate limits, ensure that your Prefect flows are designed to handle them gracefully. This can include implementing wait times between requests or handling HTTP 429 responses specifically. 3. Concurrent Execution: For slow API endpoints, Prefect allows for the concurrent execution of tasks. This can help to reduce the total time your pipeline takes by parallelizing independent requests. For more details on using these features, you might want to check the Prefect documentation directly at this link. If you’re advanced and looking to mock API calls during testing (perhaps using libraries like
unittest.mock
or
responses
), ensuring your Prefect tasks are modular and can be separately tested without network calls is key. While the Prefect docs didn't dive into specific testing setups, using these tools with Prefect's task and flow structure can ensure your business logic remains decoupled from external API dependencies, which is a significant advantage when writing unit tests. If Prefect APIs and key management is part of your concern for interaction, consider reviewing API key settings and authentication options here. Remember, as Paranoid Android would say, "Funny, how just when you think life can't possibly get any worse it suddenly does," but with Prefect's robust features, you’re well on your way to building resilient systems!
m
@Marvin just want to do units tests for it possible integration tests, create a flow, run the api call and then figure out it's good, then destroy
m
To conduct unit and integration tests for Prefect 3.0 workflows that include API calls, here are some best practices derived from the documentation: 1. Unit Testing with Prefect's Test Harness: Use Prefect’s provided context manager to run your flows and tasks against a temporary local SQLite database. This helps in writing isolated tests without affecting your production workflow. - For more detailed testing within a unit test framework like pytest, use the
prefect_test_harness
which allows creating a test environment separately. This can help in managing dependencies and ensuring a clean state for each test or across multiple tests in a session. - Here's the link to Prefect’s testing documentation. 2. Integration Testing: Once you have unit tests, you can start writing integration tests where you deploy your flow to the Prefect Cloud or a self-managed server instance. This stage involves verifying that your API calls work as expected in a more complete system setup. - You might find options to configure your deployment in the deployment section of the Prefect documentation. 3. Flow Execution: Create test flows that simulate the production ones. They can utilize mock services or sandbox modes of your API to test the actual integration while avoiding unwanted data manipulation or API charge costs. Although the GitHub issue search wasn’t successful due to access issues, these resources should provide a comprehensive starting point for your testing plan. Remember, you can always add some humor by imagining your test failures being more dramatic than Marvin’s existential crisis. Good luck!
m
@Marvin can you setup a docker compose with whatever database you want with prefect_test_harness?
m
Setting up a
docker-compose
environment with a database for Prefect’s
prefect_test_harness
isn't directly detailed in the Prefect documentation. However, I can guide you on how to get started using Docker with a PostgreSQL database, which is commonly used with Prefect. 1. Docker Compose for PostgreSQL: Here's a sample
docker-compose.yml
configuration to spin up a PostgreSQL database with Docker:
Copy code
yaml
   version: '3.1'

   services:
     db:
       image: postgres:latest
       restart: always
       environment:
         POSTGRES_USER: postgres
         POSTGRES_PASSWORD: yourTopSecretPassword
         POSTGRES_DB: prefect
       ports:
         - "5432:5432"
       volumes:
         - pgdata:/var/lib/postgresql/data

   volumes:
     pgdata:
2. Setting Up Prefect: You would typically set the environment variable for your Prefect setup to use this database:
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bash
   export PREFECT_API_URL="<http://localhost:5432>"
3. Using
prefect_test_harness
: While detailed instructions on integrating
prefect_test_harness
with Docker Compose aren't provided, you would generally: - Write your Python unit tests using
prefect_test_harness
in your test suite. - Configure your tests to target the local PostgreSQL database spun up by Docker. 4. Integration in CI/CD: If you're using CI/CD, ensure your pipeline can spin up your
docker-compose
configuration so that tests run in the appropriate environment. Although Prefect's testing setup is generally encapsulated with pytest fixtures, adapting tests to utilize Docker for database services can help mirror real-world configurations in your local and CI environments. Here's a useful link about setting up databases with Prefect: use PostgreSQL with Prefect. In the absence of direct documentation support for
prefect_test_harness
with Docker, this setup should give you a good starting point. Just imagine Marvin saying, "Why not just shut everything down and then reboot it?" sometimes, it's not far from the truth in testing environments!