bitcoin-mirror/ci

CI Scripts

This directory contains scripts for each build step in each build stage.

Running a Stage Locally

Be aware that the tests will be built and run in-place, so please run at your own risk. If the repository is not a fresh git clone, you might have to clean files from previous builds or test runs first.

The ci needs to perform various sysadmin tasks such as installing packages or writing to the user's home directory. While it should be fine to run the ci system locally on your development box, the ci scripts can generally be assumed to have received less review and testing compared to other parts of the codebase. If you want to keep the work tree clean, you might want to run the ci system in a virtual machine with a Linux operating system of your choice.

To allow for a wide range of tested environments, but also ensure reproducibility to some extent, the test stage requires bash, docker, and python3 to be installed. To run on different architectures than the host qemu is also required. To install all requirements on Ubuntu, run

sudo apt install bash docker.io python3 qemu-user-static

For some sanitizer builds, the kernel's address-space layout randomization (ASLR) entropy can cause sanitizer shadow memory mappings to fail. When running the CI locally you may need to reduce that entropy by running:

sudo sysctl -w vm.mmap_rnd_bits=28

To run a test that requires emulating a CPU architecture different from the host, we may rely on the container environment recognizing foreign executables and automatically running them using qemu. The following sets us up to do so (also works for podman):

docker run --rm --privileged docker.io/multiarch/qemu-user-static --reset -p yes

It is recommended to run the CI system in a clean environment. The env -i command below ensures that only specified environment variables are propagated into the local CI. To run the test stage with a specific configuration:

env -i HOME="$HOME" PATH="$PATH" USER="$USER" FILE_ENV="./ci/test/00_setup_env_arm.sh" ./ci/test_run_all.sh

Configurations

The test files (FILE_ENV) are constructed to test a wide range of configurations, rather than a single pass/fail. This helps to catch build failures and logic errors that present on platforms other than the ones the author has tested.

Some builders use the dependency-generator in ./depends, rather than using the system package manager to install build dependencies. This guarantees that the tester is using the same versions as the release builds, which also use ./depends.

It is also possible to force a specific configuration without modifying the file. For example,

env -i HOME="$HOME" PATH="$PATH" USER="$USER" MAKEJOBS="-j1" FILE_ENV="./ci/test/00_setup_env_arm.sh" ./ci/test_run_all.sh

The files starting with 0n (n greater than 0) are the scripts that are run in order.

Cache

In order to avoid rebuilding all dependencies for each build, the binaries are cached and reused when possible. Changes in the dependency-generator will trigger cache-invalidation and rebuilds as necessary.

Configuring a repository for CI

Primary repository

To configure the primary repository, follow these steps:

1. Register with Cirrus Runners and purchase runners.
2. Install the Cirrus Runners GitHub app against the GitHub organization.
3. Enable organisation-level runners to be used in public repositories:
   1. Org settings -> Actions -> Runner Groups -> Default -> Allow public repos
4. Permit the following actions to run:
   1. cirruslabs/cache/restore@*
   2. cirruslabs/cache/save@*
   3. docker/setup-buildx-action@*
   4. actions/github-script@*

Forked repositories

When used in a fork the CI will run on GitHub's free hosted runners by default. In this case, due to GitHub's 10GB-per-repo cache size limitations caches will be frequently evicted and missed, but the workflows will run (slowly).

It is also possible to use your own Cirrus Runners in your own fork with an appropriate patch to the REPO_USE_CIRRUS_RUNNERS variable in ../.github/workflows/ci.yml NB that Cirrus Runners only work at an organisation level, therefore in order to use your own Cirrus Runners, the fork must be within your own organisation.