How to Run CodeShip Parallel Test Pipelines Efficiently for Optimal CI Parallelization

Editor's Note: This guest blog post was reprinted with permission from the author.

When you use CloudBees CodeShip as your continuous integration (CI) server you can significantly increase the speed of your CI builds with parallel test pipelines. Pipelines allow you to run multiple commands at the same time, for instance, you can split the test suite across a few pipelines and complete the CI build much faster.

One way is to define commands via the CodeShip interface. Once parallel test pipelines are enabled, each project can have multiple test pipelines that will run in parallel.

In order to run CI builds as fast as possible, we need to ensure the parallel commands will run a subset of the test suite in a way that all the commands complete at the same time to avoid a slow pipeline bottleneck. To split the test suite, we will use Knapsack Pro with Queue Mode which does a dynamic test suite split across pipelines for Ruby and JavaScript tests to keep running our tests in an optimal way across parallel pipelines (also known as CI nodes).

# first CI node running in parallel
# RSpec tests in Knapsack Pro Queue Mode (dynamic test suite split)
KNAPSACK_PRO_CI_NODE_TOTAL=2 KNAPSACK_PRO_CI_NODE_INDEX=0 bundle exec rake knapsack_pro:queue:rspec

# second CI node running in parallel
# RSpec tests in Knapsack Pro Queue Mode (dynamic test suite split)
KNAPSACK_PRO_CI_NODE_TOTAL=2 KNAPSACK_PRO_CI_NODE_INDEX=1 bundle exec rake knapsack_pro:queue:rspec

# first CI node running in parallel
KNAPSACK_PRO_CI_NODE_TOTAL=2 KNAPSACK_PRO_CI_NODE_INDEX=0 $(npm bin)/knapsack-pro-cypress

# second CI node running in parallel
KNAPSACK_PRO_CI_NODE_TOTAL=2 KNAPSACK_PRO_CI_NODE_INDEX=1 $(npm bin)/knapsack-pro-cypress

You can learn more about Cypress test runner for E2E tests in JavaScript in this article.

If you use CodeShip Pro, then a parallel step group is defined by using the type: parallel header and then nesting all steps you want to be parallelized, as seen in this example below.

- type: parallel
  steps:
  - service: app
    command: KNAPSACK_PRO_CI_NODE_TOTAL=2 KNAPSACK_PRO_CI_NODE_INDEX=0 bundle exec rake knapsack_pro:queue:rspec
  - service: app
    command: KNAPSACK_PRO_CI_NODE_TOTAL=2 KNAPSACK_PRO_CI_NODE_INDEX=1 bundle exec rake knapsack_pro:queue:rspec

Here are more examples on how to configure CodeShip Pro parallelism.

If you would like to better understand how the dynamic test suite split works and what problems it can solve check the video.

[youtube https://www.youtube.com/watch?v=hUEB1XDKEFY&w=560&h=315\]

Running tests in parallel is a fast way to lower the time of your CI build. To make it more efficient, we can split the test suite in an optimal way across CI nodes with Knapsack Pro to keep CI nodes auto balanced and run CI builds as fast as possible.

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