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v3

Githooks

CircleCI Coverage Status Mentioned in Awesome Go goreleaser Go Report Card GitHub license GitHub Releases Git Version Go Version OS

A platform-independent hooks manager written in Go to support shared hook repositories and per-repository Git hooks, checked into the working repository. This implementation is the Go port and successor of the original implementation (see Migration).

To make this work, the installer creates run-wrappers for Githooks that are installed into the .git/hooks folders on request (by default). There's more to the story though. When one of the Githooks run-wrappers executes, Githooks starts up and tries to find matching hooks in the .githooks directory under the project root, and invoke them one-by-one. Also it searches for hooks in configured shared hook repositories.

This Git hook manager supports:

Table of Content (click to expand)

Layout and Options

Take this snippet of a Git repository layout as an example:

/
├── .githooks/
│    ├── commit-msg/          # All commit-msg hooks.
│    │    ├── validate        # Normal hook script.
│    │    └── add-text        # Normal hook script.
│    │
│    ├── pre-commit/          # All pre-commit hooks.
│    │    ├── .ignore.yaml    # Ignores relative to 'pre-commit' folder.
│    │    ├── 01-validate     # Normal hook script.
│    │    ├── 02-lint         # Normal hook script.
│    │    ├── 03-test.yaml    # Hook run configuration.
│    │    ├── docs.md         # Ignored in '.ignore.yaml'.
│    │    └── final/          # Batch folder 'final' which runs all in parallel.
│    │        ├── 01-validate # Normal hook script.
│    │        └── 02-upload   # Normal hook script.
│    │
│    ├── post-merge           # An executable file.
│    │
│    ├── post-checkout/       # All post-checkout hooks.
│    │   ├── .all-parallel    # All hooks in this folder run in parallel.
│    │   └── ...
│    ├── ...
│    ├── .images.yaml         # Container image spec for use in e.g `03-test.yaml`.
│    ├── .ignore.yaml         # Main ignores.
│    ├── .shared.yaml         # Shared hook configuration.
│    ├── .envs.yaml           # Environment variables passed to shared hooks.
│    └── .lfs-required        # LFS is required.
└── ...

All hooks to be executed live under the .githooks top-level folder, that should be checked into the repository. Inside, we can have directories with the name of the hook (like commit-msg and pre-commit above), or a file matching the hook name (like post-merge in the example). The filenames in the directory do not matter, but the ones starting with a . (dotfiles) will be excluded by default. All others are executed in lexical order according to the Go function Walk rules. Subfolders as e.g. final get treated as parallel batch and all hooks inside are by default executed in parallel over the thread pool. See Parallel Execution for details.

You can use the command line helper (a globally configured Git alias alias.hooks), that is git hooks list, to list all hooks and their current state that apply to the current repository. For this repository this looks like the following.

Execution

If a file is executable, it is directly invoked, otherwise it is interpreted with the sh shell. On Windows that mostly means dispatching to the bash.exe from https://gitforwindows.org.

All parameters and standard input are forwarded from Git to the hooks. The standard output and standard error of any hook which Githooks runs is captured together1 and printed to the standard error stream which might or might not get read by Git itself (e.g. pre-push).

Hooks can also be specified by a run configuration in a corresponding YAML file, see Hook Run Configuration.

Staged Files

Hooks related to commit events (where it makes sense, not post-commit) will also have a ${STAGED_FILES} or ${STAGED_FILES_FILE} environment variable set. By default, STAGED_FILES contains the list of staged and changed files according to git diff --cached --diff-filter=ACMR --name-only. File paths are separated by a newline \n. If you want to iterate in a shell script over them, and expect spaces in paths, you might want to set the IFS like this:

IFS="
"
for file in ${STAGED_FILES}; do
    echo "$file"
done

The ACMR filter in the git diff will include staged files that are added, copied, modified or renamed.

To enable the STAGED_FILES_FILE variable which contains the path to the file containing the paths to all staged files (separated by null-chars \0, e.g. <path>\0<path>\0) use

git config githooks.exportStagedFilesAsFile true

and read this file in bash with something like:

#!/bin/bash
while read -rd $'\\0' file; do
    echo "$file"
done < "$STAGED_FILES_FILE"

1⏎ Note: This caveat is basically there because standard output and error might get interleaved badly and so far no solution to this small problem has been tackled yet. It is far better to output both streams in the correct order, and therefore send it to the error stream because that will not conflict in anyway with Git (see fsmonitor-watchman, unsupported right now.). If that poses a real problem for you, open an issue.

Hook Run Configuration

Each supported hook can also be specified by a configuration file <hookName>.yaml where <hookName> is any supported hook name. An example might look like the following:

# The command to run.
# - if it contains path separators and is relative, it its evaluated relative to
#   the worktree of the repository where this config resides.
cmd: "dist/command-of-${env:USER}.exe"

# The arguments given to `cmd`.
args:
  - "-s"
  - "--all"
  - "${env:GPG_PUBLIC_KEY}"
  - "--test ${git-l:my-local-git-config-var}"

# If you want to make sure your file is not
# treated always as the newest version. Fix the version by:
version: 1

All additional arguments given by Git to <hookName> will be appended last onto args. All environment and Git config variables in args and cmd are substituted with the following syntax:

  • ${env:VAR} : An environment variable VAR.
  • ${git:VAR} : A Git config variable VAR which corresponds to git config 'VAR'.
  • ${git-l:VAR} : A Git config variable VAR which corresponds to git config --local 'VAR'.
  • ${git-g:VAR} : A Git config variable VAR which corresponds to git config --global 'VAR'.
  • ${git-s:VAR} : A Git config variable VAR which corresponds to git config --system 'VAR'.

Not existing environment variables or Git config variables are replaced with the empty string by default. If you use ${!...:VAR} (e.g ${!git-s:VAR }) it will trigger an error and fail the hook if the variable VAR is not found. Escaping the above syntax works with \${...}.

Sidenote: You might wonder why this configuration is not gathered in one single YAML file for all hooks. The reason is that each hook invocation by Git is separate. Avoiding reading this total file several times needs time and since we want speed and only an opt-in solution this is avoided.

Githooks defines the environment variables in this table on hooks invocation.

Parallel Execution

As in the example, all discovered hooks in subfolders <batchName>, e.g. <repoPath>/<hooksDir>/<hookName>/<batchName>/* where <hooksDir> is either

  • .githooks for repository checked-in hooks or
  • githooks, .githooks or . for shared repository hooks,

are assigned the same batch name <batchName> and processed in parallel. Each batch is a synchronisation point and starts after the one before has finished. The threadpool uses by default as many threads as cores on the system. The number of threads can be controlled by the Git configuration variable githooks.numThreads set anywhere, e.g. in the local or global Git configuration.

If you place a file .all-parallel inside <hooksDir>/<hookName>, all discovered hooks inside <hooksDir>/<hookName> are assigned to the same batch name all resulting in executing all hooks in one parallel batch.

You can inspect the computed batch name by running git hooks list --batch-name.

Supported Hooks

The supported hooks are listed below. Refer to the Git documentation for information on what they do and what parameters they receive.

It is receommended to use --maintained-hooks options during install (1, 2) to only select the hooks which are really needed, since executing the Githooks manager for all hooks might slow down Git operations (especially for reference-transaction).

  • applypatch-msg
  • pre-applypatch
  • post-applypatch
  • pre-commit
  • pre-merge-commit
  • prepare-commit-msg
  • commit-msg
  • post-commit
  • pre-rebase
  • post-checkout (non-zero exit code is wrapped to 1)
  • post-merge
  • pre-push
  • pre-receive
  • update
  • post-receive
  • post-update
  • reference-transaction
  • push-to-checkout
  • pre-auto-gc
  • post-rewrite
  • sendemail-validate
  • post-index-change

The hook fsmonitor-watchman is currently not supported. If you have a use-case for it and want to use it with this tool, please open an issue.

Git Large File Storage (Git LFS) Support

If the user has installed Git Large File Storage (git-lfs) by calling git lfs install globally or locally for a repository only, git-lfs installs 4 hooks when initializing (git init) or cloning (git clone) a repository:

  • post-checkout
  • post-commit
  • post-merge
  • pre-push

Since Githooks overwrites the hooks in <repoPath>/.git/hooks, it will also run all Git LFS hooks internally if the git-lfs executable is found on the system path. You can enforce having git-lfs installed on the system by placing a <repoPath>/.githooks/.lfs-required file inside the repository, then if git-lfs is missing, a warning is shown and the hook will exit with code 1. For some post-* hooks this does not mean that the outcome of the git command can be influenced even tough the exit code is 1, for example post-commit hooks can't fail commits. A clone of a repository containing this file might still work but would issue a warning and exit with code 1, a push - however - will fail if git-lfs is missing.

It is advisable for repositories using Git LFS to also have a pre-commit hook (e.g. examples/lfs/pre-commit) checked in which enforces a correct installation of Git LFS.

Shared Hook Repositories

The hooks are primarily designed to execute programs or scripts in the <repoPath>/.githooks folder of a single repository. However there are use-cases for common hooks, shared between many repositories with similar requirements and functionality. For example, you could make sure Python dependencies are updated on projects that have a requirements.txt file, or an mvn verify is executed on pre-commit for Maven projects, etc.

For this reason, you can place a .shared.yaml file (see specs) inside the <repoPath>/.githooks folder, which can hold a list of repositories which contain common and shared hooks. Alternatively, you can have shared repositories set by multiple githooks.shared local or global Git configuration variables, and the hooks in these repositories will execute for all local projects where Githooks is installed. See git hooks shared for configuring all 3 types of shared hooks repositories.

Below are example values for these setting.

Global Configuration

$ git config --global --get-all githooks.shared # shared hooks in global config (for all repositories)
https://github.com/shared/hooks-python.git
git@github.com:shared/repo.git@mybranch

Local Configuration

$ cd myrepo
$ git config --local --get-all githooks.shared # shared hooks in local config (for specific repository)
ssh://user@github.com/shared/special-hooks.git@v3.3.3
/opt/myspecialhooks

Example Githooks Repositories

Here are some shared hook repositories to get you started with:

Application of the hooks:

They are all fully containerized so you do not have to worry about requirements except docker.

Repository Configuration

A example config <repoPath>/.githooks/shared.yaml (see specs):

version: 1
urls:
  - ssh://user@github.com/shared/special-hooks.git@otherbranch
  - git@github.com:shared/repo.git@mybranch

The install script offers to set up shared hooks in the global Git config. but you can do it any time by changing the global configuration variable.

Supported URLS

Supported URL for shared hooks are:

  • All URLs Git supports such as:

    • ssh://github.com/shared/hooks-maven.git@mybranch and also the short scp form git@github.com:shared/hooks-maven.git
    • git://user@github.com/shared/hooks-python.git
    • file:///local/path/to/bare-repo.git@mybranch

    All URLs can include a tag specification syntax at the end like ...@<tag>, where <tag> is a Git tag, branch or commit hash. The file:// protocol is treated the same as a local path to a bare repository, see next point.

  • Local paths to bare and non-bare repositories such as:

    • /local/path/to/checkout (gets used directly)
    • /local/path/to/bare-repo.git@mybranch (gets cloned internally)

    Note that relative paths are relative to the path of the repository executing the hook. These entries are forbidden for shared hooks configured by .githooks/.shared.yaml per repository because it makes little sense and is a security risk.

Shared hooks repositories specified by URLs and local paths to bare repository will be checked out into the <installPrefix>/.githooks/shared folder (~/.githooks/shared by default), and are updated automatically after a post-merge event (typically a git pull) on any local repositories. Any other local path will be used directly and will not be updated or modified. Additionally, the update of shared hook repositories can also be triggered on other hook names by setting a comma-separated list of additional hook names in the Git configuration parameter githooks.sharedHooksUpdateTriggers on any configuration level.

You can also manage and update shared hook repositories using the git hooks shared update command.

Skip Non-Existing Shared Hooks

By default, Githooks will fail if any configured shared hooks are not available and you need to update them by running git hooks update.

By using git hooks config skip-non-existing-shared-hooks --help you can disable this behavior locally/globally or by environment variable GITHOOKS_SKIP_NON_EXISTING_SHARED_HOOKS (see env. variables) which makes Githooks skip non-existing shared hooks.

Layout of Shared Hook Repositories

The layout of these shared repositories is the same as above, with the exception that the hook folders (or files) can be at the project root as well, to avoid the redundant .githooks folder.

If you want the shared hook repository to use Githooks itself (e.g. for development purposes by using hooks from <sharedRepo>/.githooks) you can furthermore place the shared hooks inside a <sharedRepo/githooks subfolder. In that case the <sharedRepo>/.githooks folder is ignored when other users use this shared repository.

The priority to find hooks in a shared hook repository is as follows: consider hooks

  1. in <hooksDir> := <sharedRepo>/githooks, if it does not exist, consider hooks
  2. in <hooksDir> := <sharedRepo>/.githooks, if it does not exist consider hooks
  3. in <hooksDir> := <sharedRepo> as the last fallback.

Each of these directories can be of the same format as the normal .githooks folder in a single repository.

You can get the root directory of a configured shared repository with namespace <namespace> by running git hooks shared root ns:<namespace>. This might be helpful in scripts if you have common shared functionality inside this shared repository you want to use.

Shared Repository Namespace

A shared repository can optionally have a namespace associated with it. The name can be stored in a file .namespace in any possible hooks directory <hooksDir> of the shared repository, see layout. The namespace comes into play when ignoring/disabling certain hooks. See ignoring hooks. The namespace name must not contain white spaces (\s) or slashes /.

The following namespaces names are reserved internally:

  • gh-self : for hooks in the repository where Githooks runs (if no .namespace is existing).
  • gh-self-repl : for original Git hooks which were replaced by Githooks during install.

Ignoring Hooks and Files

The .ignore.yaml (see specs) files allow excluding files

  • from being treated as hook scripts or
  • hooks from being run.

You can ignore executing all sorts of hooks per Git repository by specifying patterns or explicit paths which match against a hook's (file's) namespace path. Note: Dot-files, e.g. .myfile are always ignored.

Each hook either in the current repository <repoPath>/.githooks/... or inside a shared hooks repository has a so called namespace path.

A namespace path consists of the name of the hook prefixed by a namespace , e.g. :

  <namespacePath> := ns:<namespace>/<relPath> = "ns:core-hooks/pre-commit/check-numbers.py"

where <relPath> = pre-commit/check-numbers.py is the relative path to the hook. Each shared repository can provide its own namespace.

A namespace will be used when the hook belongs to a shared hook repository and will have a default unique value if it is not defined. You can inspect all namespace paths by inspecting ns-path: in the output of git hooks list in the current repository. All ignore entries in .ignore.yaml (patterns or paths) will match against these namespace paths.

Disabling works like:

# Disable certain hooks by a pattern in this repository:
# User ignore pattern stored in `.git/.githooks.ignore.yaml`:
$ git hooks ignore add --pattern "pre-commit/**" # Store: `.git/.githooks.ignore.yaml`:
# or stored inside the repository:
$ git hooks ignore add --repository --pattern "pre-commit/**" # Store: `.githooks/.ignore.yaml`:

# Disable certain shared hooks (with namespace 'my-shared-super-hooks')
# by a glob pattern in this repository:
$ git hooks ignore add --repository --pattern "my-shared-super-hooks://pre-commit/**"

In the above example, one of the .ignore.yaml files should contain a glob pattern **/*.md to exclude the pre-commit/docs.md Markdown file. Patterns can contain double star syntax to match multiple directories, e.g. **/*.txt instead of *.txt.

The main ignore file <repoPath>/<hookDir>/.ignore.yaml applies to all hooks. Any additional <repoPath>/<hookDir>/<hookName>/.ignore.yaml file inside <hookDir> will be accumulated to the main file and patterns not starting with ns: are made relative to the folder <hookName>. You can also manage .ignore.yaml files using git hooks ignore [add|remove] --help. Consult this command documentation for further information on the pattern syntax.

Trusting Hooks

To try and make things a little bit more secure, Githooks checks if any new hooks were added we haven't run before, or if any of the existing ones have changed. When they have, it will prompt for confirmation (trust prompt) whether you accept those changes or not, and you can also disable specific hooks to skip running them until you decide otherwise. The trust prompt is always fatal meaning that failing to answer the prompt, or any other prompt error, will result in a failing Git hook. To make the runner non-interactive, see user prompts. If a hook is still active and untrusted after the prompt, Githooks will fail by default. This is useful to be sure that all hooks get executed. However, you can disabled this behavior by skipping active, untrusted hooks with git hooks config skip-untrusted-hooks --enable or by setting GITHOOKS_SKIP_UNTRUSTED_HOOKS (see env. variables).

The accepted checksums are maintained in the <repoPath>/.git/.githooks.checksum directory, per local repository. You can however use a global checksum directory setup by making an absolute symbolic link with name .githooks.checksum inside the template directory (init.templateDir) which gets installed in each clone.

If the repository contains a <repoPath>/.githooks/trust-all file, it is marked as a trusted repository. Consult git hooks trust --help. On the first interaction with hooks, Githooks will ask for confirmation that the user trusts all existing and future hooks in the repository, and if she does, no more confirmation prompts will be shown. This can be reverted by running git hooks config trust-all --reset command. This is a per-repository setting. Consult git hooks config trust-all --help for more information.

You can also trust individual hooks by using git hooks trust hooks --help.

Disabling Githooks

To disable running any Githooks locally or globally, use the following:

# Disable Githooks completely for this repository:
$ git hooks disable # Use --reset to undo.
# or
$ git hooks config disable --set # Same thing... Config: `githooks.disable`


# Disable Githooks globally (for all repositories):
$ git hooks disable --global # Use --reset to undo.
# or
$ git hooks config disable --set --global # Same thing... Config: `githooks.disable`

Also, as mentioned above, all hook executions can be bypassed with a non-empty value in the GITHOOKS_DISABLE environment variable.

Environment Variables

All of these environment variables are either defined during Githooks runner executing or affect its behavior. These should mostly only be used locally and not globally be defined.

Environment Variables Effect
GITHOOKS_OS (defined by Githooks) The operating system.
See Exported Environment Variables.
GITHOOKS_ARCH (defined by Githooks) The system architecture.
See Exported Environment Variables.
STAGED_FILES (defined by Githooks) All staged files. Only set in pre-commit, prepare-commit-msg and commit-msg hook.
GITHOOKS_CONTAINER_RUN (defined by Githooks) If a hook is run over a container, this variable is set and true
GITHOOKS_DISABLE If defined, disables running hooks run by Githooks,
except git lfs and the replaced old hooks.
GITHOOKS_RUNNER_TRACE If defined, enables tracing during
Githooks runner execution. A value of 1 enables more output.
GITHOOKS_LOG_LEVEL A value debug, info, warn, error or disable sets the log level during
Githooks runner execution.
GITHOOKS_SKIP_NON_EXISTING_SHARED_HOOKS=true Skips on true and fails on false (or empty) for non-existing shared hooks.
See Trusting Hooks.
GITHOOKS_SKIP_UNTRUSTED_HOOKS=true Skips on true and fails on false (or empty) for untrusted hooks.
See Trusting Hooks.

Arguments to Shared Hooks

You can pass arguments to shared hooks currently by specifying a .githooks/.envs.yaml file which will export environment variables when running the shared hooks selected by its namespace:

envs:
  mystuff:
    # All these variables are exported
    # for shared hook namespace `mystuff`.
    - "MYSTUFF_CHECK_DEAD_CODE=1"
    - "MYSTUFF_STAGE_ON_FORMAT=1"

  sharedA:
    # All these variables are exported
    # for shared hook namespace `sharedA`.
    - "SHAREDA_ABC=1"
    - "SHAREDA_TWEET=1"

Log & Traces

You can see how the Githooks runner is been called by setting the environment variable GITHOOKS_RUNNER_TRACE to a non empty value.

GITHOOKS_RUNNER_TRACE=1 git <command> ...

Installing or Removing Run-Wrappers

You can install and uninstall run-wrappers inside a repository with git hooks install. or git hooks uninstall. This installs and uninstalls wrappers from ${GIT_DIR}/hooks as well as sets and unsets local Githooks-internal Git configuration variables.

To install run-wrappers for only selective hooks, use --maintained-hooks, e.g.

cd repository
git hook install \
    --maintained-hooks "!all, pre-commit, pre-merge-commit, prepare-commit-msg, commit-msg, post-commit" \
    --maintained-hooks "pre-rebase, post-checkout, post-merge, pre-push"

Note: Git LFS hooks is properly taken care of when --maintained-hooks is used. That is, when you don't select a Git LFS hooks in --maintained-hooks, the missing Git LFS hooks will be installed too.

Running Hooks in Containers

You can run hooks containerized over a container manager such as docker. This relieves the maintainer of a Githooks shared repo from dealing with "It works on my machine!"

To enable containerized hook runs set the Git config variable either locally or globally with

git hooks config enable-containerized-hooks [--global] --set true

or use the environment variable GITHOOKS_CONTAINERIZED_HOOKS_ENABLED=true.

Optionally set the container manager (default is docker) like

git hooks config container-manager-types [--global] --set "podman,docker"

The container manager types can be a list from [docker, podman] where the first valid one is used to run the hooks.

Running a hook in a container is achieved by specifying the image reference (image name) inside a hook run configuration, e.g. <hooksDir>/pre-commit/myhook.yaml. This works for normal repositories as well as for shared Githooks repositories.

For a shared repository, the file sharedRepo/githooks/pre-commit/checkit.yaml might look like

version: 3
cmd: ./myscripts/checkit.sh
args:
image:
  reference: "my-shellcheck:1.2.0"

which will launch the command ./myscript/checkit.sh in a container my-shellcheck:1.2.0. The current Git repository where this hook is launched is mounted as the current working directory and the relative path ./myscript/checkit.sh will be mangled to a path in the mounted read-only volume of this shared Githooks repo sharedRepo which is cached inside <installDir>/shared.

Note: When running a hook script or command over a container, you will not have access to the same environment variables as on your host system. All Githooks environment variables are forwarded however to the container run.

Note: The images you run must be rootless (contain a USER statement) and this user must have user/group id 1000 (Todo: We can loosen this requirement if really needed). See the example.

Podman Manager (rootless)

This manager is strongly preferred due to better security and less hassle with volume mounts.

The containers are run with the following flags to podman:

  • --userns=keep-id:uid=1000,gid=1000: User namespace mapping. Maps the user/group id of the user running Githooks (your host user) to the container user/group id 1000. This means a host user with user/group id e.g. 4000 will be seen inside the container as user/group id 1000. This also works for all volume mounts which will have 1000:1000 permission inside the container.

Docker Manager

The containers are run with the following flags to docker:

  • --user:<uid>:<gid>: The container is run as the same user id and group id as the user which runs Githooks (your host user). See the note below why this is the case.

Note: Running commands in containers which modify files on writable volumes has some caveats and quirks with permissions which are host system dependent. Hongli Lai summarized these troubles in a very good article. Long story short if the images are run with the docker manager, you should use MatchHostFsOwner which counter acts these permission problems neatly by installing this into your hook's sidecar container.

Pull and Build Integration

To have this containerized functionality neatly integrated, Githooks provides a way for specifying image pull and build options in an opt-in file <hooksDir>/.images.yaml (see <hooksDir> definition), e.g.

version: 1
images:
  koalaman/shellcheck:latest:
  # will pull the image reference according to this dictionary key.

  my-shellcheck:1.2.0:
    pull: # optional
      reference: myimages/${namespace}-shellcheck:v0.9.0

  ${namespace}-my-shellcheck:1.3.0:
    build:
      dockerfile: ./.githooks/docker/Dockerfile
      stage: myfinalstage
      context: ./.githooks/docker

This file will be acted upon when shared hooks are updated, e.g. git hooks shared update or when this happens automatically.

You can trigger the image pull/build procedure by running

git hooks images update [--config ...]

inside a normal repo a which configures such a file in a/.githooks/.images.yaml or in a normal repository b which configures to use a sharedRepo in .shared.yaml which configures it in sharedRepo/githooks/.images.yaml. If this shared repo sharedRepo has a namespace banana configured, git hooks images update in b will trigger

  • a pull of image koalaman/shellcheck:latest,
  • a pull of image myimages/banana-shellcheck:v0.9.0 and tagging it with my-shellcheck:1.2.0,
  • and a build of an image banana-my-shellcheck:1.3.0 of stage myfinalstage in the respective Dockerfile ./.githooks/docker/Dockerfile where the build context is set to .githooks/docker.

Note: All paths in the build specification build: are relative to the repository root where this .images.yaml is located.

Locate Githooks Container Images

All built images are automatically labeled with githooks-version to make them easy to retrieve, e.g.

docker images --filter label=githooks-version

or to easily delete all of them by

docker rmi $(docker images -f "label=githooks-version" -q)

Pruning Of Older Images: If a shared repository is updated from git hooks shared update it might come with new images references in .images.yaml. Githooks does not yet detect which references are no longer needed after the pull/build procedure nor does it offer a way yet to prune older images (just use the above).

Running Hooks/Scripts Manually

The command git hooks exec helps to launch executables and run configuration the same as Githooks does when run normally. This features simplifies executing add-on scripts/executables distributed in shared hook repositories (and also locally with ns:gh-self).

For example execute the following add-on 'format-all' script in this shared repository with:

git hooks exec --containerized \
  ns:githooks-docs/scripts/format-docs-all.yaml -- \
  --force \
  --dir ./

This will launch the specified container and run the script.

Note: You need to have configured this shared repository inside your repo where you use Githooks and it needs to be available with git hooks shared update.

User Prompts

Githooks shows user prompts during installation, updating (automatic or manual), uninstallation and when executing hooks (the runner executable).

The runner might get executed over a Git GUI or any other environment where no terminal is available. In this case all user prompts are shown as GUI dialogs with the included platform-independent dialog tool. The GUI dialog fallback is currently only enabled for the runner.

Githooks distinguishes between fatal and non-fatal prompts.

  • A fatal prompt will result in a complete abort if

    • The prompt could not be shown (terminal or GUI dialog).
    • The answer returned by the user is incorrect (terminal only) or the user canceled the GUI dialog.

  • A non-fatal prompt always has a default answer which is taken in the above failing cases and the execution continues. Warning messages might be shown however.

The runner will show prompts, either in the terminal or as GUI dialog, in the following cases:

  1. Trust prompt: The user is required to trust/untrust a new/changed hook: fatal.
  2. Update prompts: The user is requested to accept a new update if automatic updates are enabled (git hooks update --enable-check): non-fatal.
    • Various other prompts when the updater is launched: non-fatal.

User prompts during runner execution are sometimes not desirable (server infrastructure, docker container, etc...) and need to be disabled. Setting git hooks config non-interactive-runner --enable --global will:

  • Take default answers for all non-fatal prompts. No warnings are shown.
  • Take default answer for a fatal prompt if it is configured: The only fatal prompt is the trust prompt which can be configured to pass by executing git hooks config trust-all --accept.

Installation

Quick (Secure)

Launch the below shell command. It will download the release from Github and launch the installer.

Note: All downloaded files are checksum & signature checked.

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash

See the next sections on different install options.

Note: Use bash -s -- -h above to show the help message of the bootstrap script and bash -s -- -- <options> to pass arguments to the installer (cli installer), e.g. bash -s -- -- -h to show the help.

Package Manager nix

Githooks is inside nixpkgs, so you can access it by pkgs.githooks in your flake.nix.

To install the Githooks derivation at a different version <version>, add the following to your inputs in your flake.nix:

inputs = {
    githooks = {
      url = "github:gabyx/githooks?dir=nix&ref=v<version>";
      inputs.nixpkgs.follows = "nixpkgs";
    };
}

You should never install a major version upgrade as Githooks should be uninstalled completely before. The uninstaller on any version however should work backward-compatible.

and then use it in your packages, e.g. here with home-manager by doing:

{ lib, pkgs, inputs, ...}:
let
  githooks = inputs.githooks.packages."${pkgs.system}".default;
in {
  home.packages = [githooks]
}

Procedure

The installer will:

  1. Download the current binaries if --update is not given. Optionally it can use a deploy settings file to specify where to get the binaries from. (default is this repository here.)

  2. Verify the checksums and signature of the downloaded binaries.

  3. Launch the current installer which proceeds with the next steps. If --update is given the newest Githooks is downloaded and installed directly.

  4. Find the install mode relevant hooks directory <hooksDir>:

    • Use the directory given with --hooks-dir <dir> on the command line.

    • Use git config --get githooks.pathForUseCoreHooksPath if Githooks is already installed.

    • Use the following template directory if --hooks-dir-use-template-dir is given:

      1. Use GIT_TEPMLATE_DIR if set and add /hooks
      2. Use Git config value init.templateDir if set and add /hooks
      3. Use <install-dir>/templates/hooks.

      Note: This will silently make all new repositories with git init or git clone directly use Githooks, this is similar to the centralized install mode.

  5. Write all Githooks run-wrappers into the hooks directory <hooksDir> and

    • Set core.hooksPath for centralized install mode (--centralized).

  6. Offer to enable automatic update checks.

  7. Offer to find existing Git repositories on the file system (disable with --skip-install-into-existing)

    1. Make them use Githooks by either setting core.hooksPath (or install run-wrappers if <repo-git-dir>/hooks/githooks-contains-run-wrappers exists).

    2. Offer to add an intro README in their .githooks folder.

  8. Install/update run-wrappers into all registered repositories: Repositories using Githooks get registered in the install folders registered.yaml file on their first hook invocation.

  9. Offer to set up shared hook repositories.

Install Modes

This installer can install Githooks in one of 2 ways:

  • Manual: To use Githooks in a repo, it must be installed (default behavior) with git hooks install.

  • Centralized: Using the Git core.hooksPath global variable (set by passing the --centralized parameter to the install script). All repositories will use Githooks by default.

Read the details about the differences between these 2 approaches below.

Install Mode - Manual

This is the default installation mode.

In this mode, you decide yourself when to use Githooks in a repository simply by doing one of the following with the same effect:

  • Run git hooks install or git hooks uninstall to install run wrappers explicitly.

This means that Githooks might not run if you forget to install the hooks.

To install Githooks on your system, simply execute cli installer. It will guide you through the installation process. Check the cli installer --help for available options. Some of them are described below:

Its advised to only install Githooks for a selection of the supported hooks by using --maintained-hooks as

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --maintained-hooks "!all, pre-commit, pre-merge-commit, prepare-commit-msg, commit-msg, post-commit" \
    --maintained-hooks "pre-rebase, post-checkout, post-merge, pre-push"

You can still overwrite selectively for a repository by installing another set of hooks. Missing Git LFS hooks will always be placed if necessary.

If you want, you can try out what the script would do first, without changing anything by using:

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --dry-run

Optionally, you can also pass the hooks directory to which you want to install the Githooks run-wrappers by appending --hook-dir <path> to the command above, for example:

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --hooks-dir /home/public/myhooks

Install Mode - Centralized Hooks

You have the option to install Githooks centralized which will use the run-wrappers globally by setting the global core.hooksPath additionally. For this, run the command below.

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --centralized

Install from different URL and Branch

If you want to install from another Git repository (e.g. from your own or your companies fork), you can specify the repository clone url as well as the branch name (default: main) when installing with:

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --clone-url "https://server.com/my-githooks-fork.git" \
    --clone-branch "release"

The installer always maintains a Githooks clone inside <installDir>/release for its automatic update logic. The specified custom clone URL and branch will then be used for further updates in the above example (see update mechanics).

Because the installer always downloads the latest release (here from another URL/branch), it needs deploy settings to know where to get the binaries from. Either your fork has setup these settings in their Githooks release (you hopefully downloaded) already or you can specify them by using --deploy-api <type> or the full settings file --deploy-settings <file>. The <type> can either be gitea ( or github which is not needed since it can be auto-detected from the URL) and it will automatically download and verify the binaries over the implemented API. Credentials will be collected over git credential to access the API. [@todo].

Use in CI

The installation depends on how you use Githooks in CI. The general approach is to run functionality or hooks over Githooks in CI only containerized. Doing it without containerization will be brittle and non-robust and requires you to have all needed tools installed in the running environment, also potentially the tools used in shared hook repositories.

There are generally two scenarios how you would use Githooks in CI.:

  1. Run functionality in hook repositories (local and shared repos): This can be done by using git hooks exec --containerized .... The following

    git hooks exec --containerized \
   ns:githooks-shell/scripts/check-shell-all.yaml -- --force --dir "."

    would run the config scripts/check-shell-all.yaml (see hook run configuration) from the hook repository githooks-shell containerized.

  2. Run hooks containerized directly, e.g. pre-commit over a crafted git commit, to check all staged files in that commit with all hooks specified in the respective repository. This repository does exactly that in tests/test-lint.sh.

  3. Run 1. or 2. but with nix-shell support if hooks are setup like this. No containers needed, no nested container troubles. Not implemented yet.

Warnings: Running a containerized hook or script in CI might mean that a container starts as a nested container since your CI already uses a top-level container which itself has access to docker or podman. Nested containers are kind of tricky and mind-boggling. Githooks will launch a container with two mounts

  • the workspace (the repository on which Githooks runs, e.g. /data/repo) bind mounted to /mnt/workspace and
  • the shared hook repository (~/.githooks/shared) bind mounted to /mnt/shared,

inside the hook container.

These mounts can be influenced with the env. variable GITHOOKS_CONTAINER_RUN_CONFIG_FILE, see below.

Nested Containers

Some nomenclature for the next explanations: the host is considered a VM (your CI instance) and the top-level container T is your CI container you started on this VM for a dedicated CI job (C has access to a container manager). The nested container N is a launched container from Githooks.

Adjusting the mounts is needed because for the nested container N (inside C), the mounts might not work because the source paths (e.g. /data/repo in -v /data/repo:/mnt/workspace) are interpreted where the container manager service runs. E.g. for docker, when you mount the docker socket into the top-level container to have connect to the docker instance (running on the host, generally not the best security practice!), then that would be the host and the paths would not exist (e.g. there is no /data/repo on the host). If you have a full container manager (podman preferred) inside container T, it is different. In that case, the mount paths are interpreted inside container T. The mounts might still not work because the paths cannot be mounted further into a nested container N due to restrictions what you can mount to nested containers - if the path comes from a bind mount from the host (VM) into C it does not work (AFAIK). In that case you can workaround this by GITHOOKS_CONTAINER_RUN_CONFIG_FILE which is the path to a YAML file which modifies the mounts:

version: 1

# Tell Githooks where the workspace will be in the nested container.
# (optional, default `/mnt/workspace`)
workspace-path-dest: /tmp/ci-job-1/build/repo
# Tell Githooks where the shared repository checkouts are in the nested container.
# (optional, default: `/mnt/shared`)
shared-path-dest: /tmp/ci-job-1/githooks-install/.githooks/shared

# Do not auto-mount the workspace (bind mount), do it yourself with args.
# (optional, default: true)
auto-mount-workspace: false
# Do not auto-mount the shared (bind mount), do it yourself with args.
# (optional, default: true)
auto-mount-shared: false

# Additional arguments to `docker run` or `podman run`.
args: ["-v", "gh-test-tmp:/tmp"]

The above will mount a volume gh-test-tmp volume to /tmp in N where Githooks will find the workspace under /tmp/ci-job-1/build/repo and the shared repository checkouts in /tmp/ci-job-1/githooks-install/.githooks/shared.

Note: You can use whatever docker run or podman run accepts. To mention is --volumes-from where you can mount the same volumes from another containers id.

Gitlab Demo

The repository Markdown2PDF contains a CI setup in .gitlab/pipeline.yaml for Gitlab

For Gitlab this boils down to following pipeline step which uses dockerized hooks:

format:
  stage: <your-stage-name>
  image: docker:24
  rules:
    - *defaults-rules
  services:
    - docker:24-dind
  variables:
    GITHOOKS_INSTALL_PREFIX: "$CI_BUILDS_DIR/githooks"
  script:
    - apk add git jq curl bash just findutils parallel
    - just format

where just format will call the following function:

function ci_setup_githooks() {
    mkdir -p "$GITHOOKS_INSTALL_PREFIX"

    printInfo "Install Githooks."
    curl -sL "https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh" |
        bash -s -- -- --non-interactive --prefix "$GITHOOKS_INSTALL_PREFIX"

    git hooks config enable-containerized-hooks --global --set

    printInfo "Pull all shared Githooks repositories."
    git hooks shared update
}

which then enables you to call side-car scripts in the hook repository, e.g. as demonstrated which will run over containers the same as in non-CI use cases:

function run_format_shared_hooks() {
    printInfo "Run all formats scripts in shared hook repositories."
    git hooks exec --containerized \
        ns:githooks-shell/scripts/format-shell-all.yaml -- --force --dir "."

    git hooks exec --containerized \
        ns:githooks-configs/scripts/format-configs-all.yaml -- --force --dir "."

    git hooks exec --containerized \
        ns:githooks-docs/scripts/format-docs-all.yaml -- --force --dir "."

    git hooks exec --containerized \
        ns:githooks-python/scripts/format-python-all.yaml -- --force --dir "."
}

No Installation

You can use this hook manager also without a global installation. For that you can clone this repository anywhere (e.g. <repoPath>) and build the executables with Go by running githooks/scripts/build.sh --prod. You can then use the hooks by setting core.hooksPath (in any suitable Git config) to the checked in run-wrappers in <repoPath>/hooks like so:

git clone https://github.com/gabyx/githooks.git githooks
cd githooks
githooksRepo=$(pwd)
scripts/build.sh

Then, to globally enable them for every repo:

git config --global core.hooksPath "$gihooksRepo/hooks"

or locally enable them for a single repo only:

cd repo
git config --local core.hooksPath "$githooksRepo/hooks"

Non-Interactive Installation

You can also run the installation in non-interactive mode with the command below. This will determine an appropriate template directory (detect and use the existing one, or use the one passed by --template-dir, or use a default one), install the hooks automatically into this directory, and enable periodic update checks.

The global install prefix defaults to ${HOME} but can be changed by using the options --prefix <installPrefix>:

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --non-interactive [--prefix <installPrefix>]

It's possible to specify which template directory should be used, by passing the --template-dir <dir> parameter, where <dir> is the directory where you wish the templates to be installed.

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --template-dir "/home/public/.githooks-templates"

By default the script will install the hooks into the ~/.githooks/templates/ directory.

Install on the Server

On a server infrastructure where only bare repositories are maintained, it is best to maintain only server hooks. This can be achieved by installing with:

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- -- \
    --maintained-hooks "server"

The global template directory then only contains the following run-wrappers for Githooks:

  • pre-push
  • pre-receive
  • update
  • post-receive
  • post-update
  • reference-transaction
  • push-to-checkout
  • pre-auto-gc

which get deployed with git init or git clone automatically. See also the setup for bare repositories.

Setup for Bare Repositories

If you want to use Githooks with bare repositories on a server, you should setup the following to ensure smooth operations (see user prompts):

cd bareRepo
# Install Githooks into this bare repository
git hooks install

# Automatically accept changes to all existing and new
# hooks in the current repository.
# This makes the fatal trust prompt pass.
git hooks config trust-all-hooks --accept

# Don't do global automatic updates, since the Githooks updater
# might get invoked in parallel on a server.
git hooks config update --disable-check

Note: A user cannot change bare repository Githooks by pushing changes to a bare repository on the server. If you use shared hook repositories in you bare repository, you might consider disabling shared hooks updates by git hooks config disable-shared-hooks-update --set.

Global Hooks or No Global Hooks

Manual: Use Githooks Selectively

In this approach, the install script installs the hook run-wrapper into a common location (~/.githooks/templates/ by default).

To make Githooks available inside a repository, you must install it with

cd repo
git hooks install

which will simply set the core.hooksPath to the common location where Githooks maintains its run-wrappers. If you want a partial maintained hooks set with git hooks install --maintained-hooks ..., it will switch to install Githooks run-wrappers inside this sole repository.

You have the possibility to install the Githooks run-wrappers into a Git template directory (e.g. GIT_TEMPLATE_DIR or init.templateDir or the default Git template directory from the Git install) by specifying --hooks-dir-use-template-dir. This option is discouraged and only available for backward compatibility and is not really needed and can be covered with the below centralized install mode.

Centralized: Use Githooks For All Repositories

In this approach, the install script installs the hook run-wrapper into a common location (~/.githooks/templates/ by default) and sets the global core.hooksPath variable to that location. Git will then, for all relevant actions, check the core.hooksPath location, instead of the default ${GIT_DIR}/hooks location.

This approach works more like a blanket solution, where all repositories2 will start using the Githooks run-wrappers (thus launching Githooks), regardless of their location.

2⏎ Note: It is possible to override the behavior for a specific repository, by setting a local core.hooksPath variable with value ${GIT_DIR}/hooks, which will revert Git back to its default behavior for that specific repository. You don't need to initialize git lfs install, because they presumably be already in ${GIT_DIR}/hooks from any git clone/init. This does NOT work when using this inside a Git worktree.

Updates

You can update the Githooks any time by running

git hooks update

or one of the install commands above with --update.

It then downloads the binaries (GPG signed + checksummed) and dispatches to the new installer to install the new version. It will update itself and simply overwrite the template run-wrappers with the new ones, and if you opt-in to install into existing or registered local repositories, those will get overwritten too.

Automatic Update Checks

You can also enable automatic update checks during the installation, that is executed once a day after a successful commit. It checks for a new version where you can then call git hooks update your-self (*previous to version 3 this was automatic which was removed).

Automatic updates can be enabled or disabled at any time by running the command below.

# enable with:
$ git hooks update --enable-check # `Config: githooks.updateCheckEnabled`

# disable with:
$ git hooks update --disable-check

Update Mechanics

The update mechanism works by tracking the tags on the Git branch (chosen at install time) which is checked out in <installDir>/release. Normally, if there are new tags (versions) available, the newest tag (version) is installed. However, prerelease version tags (e.g. v1.0.0-rc1) are generally skipped. You can disable this behavior by setting the global Git config value githooks.updateCheckUsePrerelease = true. Major version updates are never automatically installed an need the consent of the user.

If the annotated version tag or the commit message it points to (git tag -l --format=%(contents) <tag>) contains a trailing header which matches the regex ^Update-NoSkip: *true, than this version will not be skipped. This feature enables to enforce an update to a specific version. In some cases this is useful (serialization changes etc.).

The single-line commit trailers ^Update-Info: *(.*) (multiple ones allowed) on the annotated tag is used to assemble a small changelog during update, which is presented to the user. The single line can contain important information/links to relevant fixes and changes.

You can also check for updates at any time by executing git hooks update or using git hooks config update-check [--enable|--disable] command to enable or disable the automatic update checks.

Uninstalling

If you want to get rid of this hook manager, you can execute the uninstaller <installDir>/bin/uninstaller by

git hooks uninstaller

or

curl -sL https://raw.githubusercontent.com/gabyx/githooks/main/scripts/install.sh | bash -s -- --uninstall

This will delete the run-wrappers installed in the template directory, optionally the installed hooks from the existing local repositories, and reinstates any previous hooks that were moved during the installation.

YAML Specifications

You can find YAML examples for hook ignore files .ignore.yaml and shared hooks config files .shared.yaml here.

Migration

Migrating from the sh implementation here is easy, but unfortunately we do not yet provide an migration option during install (PRs welcome) to take over Git configuration values and other not so important settings.

However, you can take the following steps for your old .shared and .ignore files inside your repositories to make them work directly with a new install:

  1. Convert all entries in .ignore files to a pattern in a YAML file .ignore.yaml (see specs). Each old glob pattern needs to be prepended by **/ (if not already existing) to make it work correctly (because of namespaces), e.g. a pattern .*md becomes **/.*md. Disable shared repositories in the old version need to be reconfigured, by using ignore patterns. Check if the ignore is working by running [git hooks list](docs/cli/git_hooks_list.md).

  2. Convert all entries in .shared files to an url in a YAML file .shared.yaml here.

  3. It's heartly recommended to first uninstall the old version, to get rid of any old settings.

  4. Install the new version.

Trusted hooks will be needed to be trusted again. To port Git configuration variables use the file githooks/hooks/gitconfig.go which contains all used Git config keys.

Dialog Tool

Githooks provides it's own platform-independent dialog tool dialog which is located in <installDir>/bin. It enables the use of native GUI dialogs such as:

  • options dialog
  • entry dialog
  • file save and file selection dialogs
  • message dialogs
  • system notifications

inside of hooks and scripts. See the screenshots.

Why another tool?: At the moment of writing there exists no proper platform-independent GUI dialog tool which is bomb-proof in it's output and exit code behavior. This tool should really enable proper and safe usage inside hooks and other scripts. You can even report the output in json format (use option --json). It was heavily inspired by zenity and features some of the same properties (no cgo, cancellation through context). You can use this dialog tool independently of Githooks.

Test it out! 🎉: Please refer to the documentation of the tool.

Build From Source

cd githooks
go mod download
go mod vendor
cd githooks/apps/dialog
go build ./...
./dialog --help

Dependencies

The dialog tool has the following dependencies:

  • macOS : osascript which is provided by the system directly.
  • Unix : A dialog tool such as zenity (preferred), qarma or matedialog.
  • Windows: Common Controls 6 which is provided by the system directly.

Tests and Debugging

Running the integration tests with Docker:

cd githooks
bash tests/test-alpine.sh # and other 'test-XXXX.sh' files...

Run certain tests only:

bash tests/test-alpine.sh --seq {001..120}
bash tests/test-alpine.sh --seq 065

Debugging in the Dev Container

There is a docker development container for debugging purposes in .devcontainer. VS Code can be launched in this remote docker container with the extension ms-vscode-remote.remote-containers. Use Remote-Containers: Open Workspace in Container... and Remote-Containers: Rebuild Container.

Once in the development container: You can launch the VS Code tasks:

  • [Dev Container] go-delve-installer
  • etc...

which will start the delve debugger headless as a server in a terminal. You can then attach to the debug server with the debug configuration Debug Go [remote delve]. Set breakpoints in the source code to trigger them.

Todos

  • Finish deploy settings implementation for Gitea and others.

Changelog

Version v2.x.x

For upgrading from v1.x.x to v2.x.x consider the braking change documentation.

FAQ

  • Shell on Windows shows weird characters: Githooks outputs UTF-8 characters (emojis etc.). Make sure you have the UTF-8 codepage active by doing chcp.com 65001 (either in cmd.exe or git-bash.exe, also from an integrated terminal in VS Code). You can make it permanent by putting this into the startup scripts of your shell, e.g. (.bashrc). Consider using Windows Terminal.

Acknowledgements

Authors

  • Gabriel Nützi (Go implementation)
  • Viktor Adam (Initial sh implementation)
  • Matthijs Kooijman (suggestions & discussions)
  • and community.

Support & Donation

When you use Githooks and you would like to say thank you for its development and its future maintenance: I am happy to receive any donation which will be distributed equally among all contributors.

paypal

License

MIT

About

🦎 Githooks: per-repo and shared Git hooks with version control and auto update. [✩Star] if you're using it!

Topics

git go docker linting formatting best-practices git-hooks containerization

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