What are some examples of using parallelism in CircleCI?

What are some examples of using parallelism in CircleCI?

CircleCI allows you to run jobs in parallel to speed up your CI/CD pipeline. For example, you can run tests for different services simultaneously.

Can you give me a specific YAML configuration example?

Sure! Here's a simple example:

version: 2.1
jobs:
  test:
    docker:
      - image: circleci/python:3.8
    steps:
      - checkout
      - run: pytest tests/
  lint:
    docker:
      - image: circleci/python:3.8
    steps:
      - checkout
      - run: flake8 .
workflows:
  version: 2
  test_and_lint:
    jobs:
      - test
      - lint:
          requires:
            - test

How does this improve the build time?

By running jobs in parallel, you can significantly reduce the overall build time. Instead of waiting for each job to finish sequentially, they execute at the same time.

Are there any limitations to using parallelism?

Yes, there are some limitations, such as the maximum number of concurrent jobs allowed based on your CircleCI plan and potential resource contention.