shellcheck-gha

This Python script extracts shell scripts from GitHub workflows (jobs.<job_id>.steps[*].run) and runs them against ShellCheck.

• shellcheck-gha
  • Installation
    • Using GitHub Actions (recommended)
    • PyPI
    • From Source
  • Usage
  • Example
  • Goals
  • Non-Goals

Installation

Requirements:

• Python ≥ 3.11
• ShellCheck ≥ 0.9.0, available on apt, brew, cabal, dnf, and pkg.

Using GitHub Actions (recommended)

The shellcheck-gha project can be used as a GitHub Workflow step:

on:
  push:
    paths:
      - .github/**
  pull_request:
    paths:
      - .github/**

permissions:
  contents: read

jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Run ShellCheck
        uses: saleor/shellcheck-gha@v0
        # Uncomment to customize the scan directory:
        # with:
        #   scan-directory-path: .github/

PyPI

The project is hosted on PyPI at https://pypi.org/project/shellcheck-gha/. To install the project, run:

$ pip install shellcheck-gha

From Source

Alternatively, the project can be cloned and installed using poetry.

$ git clone https://github.com/saleor/shellcheck-gha
$ pip install poetry
$ poetry install
$ shellcheck-gha --help

Usage

$ shellcheck-gha --help
usage: shellcheck-gha [-h] [--default-shell DEFAULT_SHELL] [--verbose] [--debug] [--skip-unknown-files | --no-skip-unknown-files] [directory]

positional arguments:
  directory

options:
  -h, --help            show this help message and exit
  --default-shell DEFAULT_SHELL
                        The default shell running in the workflow(s)
  --verbose             Show more details about the execution.
  --debug               Add debug information (takes precedence over --verbose).
  --skip-unknown-files, --no-skip-unknown-files
                        Whether to exit with an error on when parsing non-GitHub workflow or composite action YAML files. Skipping is useful when a directory
                        may be mixed with other YAML files (e.g. config files such as .github/dependabot.yaml). Unknown files are skipped by default.

Example

$ shellcheck-gha .
=== Results: 2 file(s) have findings ===
Scanned 5 files (16 shell scripts)
[INFO] In bad.yaml:
    Message: Double quote to prevent globbing and word splitting.
    More information: https://www.shellcheck.net/wiki/SC2086
    Code:
        test $USE_GITIGNORE == true
             ^^^^^^^^^^^^^^^
[INFO] In tests/sample_workflows/with-findings.yaml:
    Message: Double quote to prevent globbing and word splitting.
    More information: https://www.shellcheck.net/wiki/SC2086
    Code:
        echo $BAD_JOB1
             ^^^^^^^^^^
[INFO] In tests/sample_workflows/with-findings.yaml:
    Message: Double quote to prevent globbing and word splitting.
    More information: https://www.shellcheck.net/wiki/SC2086
    Code:
        echo $BAD_JOB2
             ^^^^^^^^^^

Goals

• Only check *nix related shells (sh, bash, ksh)
• Provide useful logs that allow the users to quickly find the problematic code in their workflow.

Non-Goals

• Differential checking (base vs head commit)
• Logical understanding of GitHub workflows, such as (but not limited to):
  • Handling defaults.run.shell
  • Support for string interpolation (${{ ... }})
• Tracking down exact locations of the findings (line numbers, columns)