Customizing through a python class

The basic steps are:

1. Inheriting from BaseCommitizen.
2. Give a name to your rules.
3. Create a Python package using proper build backend
4. Expose the class as a commitizen.plugin entrypoint.

Check an example on how to configure BaseCommitizen.

You can also automate the steps above through cookiecutter.

cookiecutter gh:commitizen-tools/commitizen_cz_template

See commitizen_cz_template for details.

See Third-party plugins for more details on how to create a third-party Commitizen plugin.

Custom commit rules

Create a Python module, for example cz_jira.py.

Inherit from BaseCommitizen, and you must define questions and message. The others are optional.

cz_jira.py

from commitizen.cz.base import BaseCommitizen
from commitizen.defaults import Questions


class JiraCz(BaseCommitizen):
    # Questions = Iterable[MutableMapping[str, Any]]
    # It expects a list with dictionaries.
    def questions(self) -> Questions:
        """Questions regarding the commit message."""
        questions = [
            {"type": "input", "name": "title", "message": "Commit title"},
            {"type": "input", "name": "issue", "message": "Jira Issue number:"},
        ]
        return questions

    def message(self, answers: dict) -> str:
        """Generate the message with the given answers."""
        return f"answers['title'] (#answers['issue'])"

    def example(self) -> str:
        """Provide an example to help understand the style (OPTIONAL)

        Used by `cz example`.
        """
        return "Problem with user (#321)"

    def schema(self) -> str:
        """Show the schema used (OPTIONAL)

        Used by `cz schema`.
        """
        return "<title> (<issue>)"

    def info(self) -> str:
        """Explanation of the commit rules. (OPTIONAL)

        Used by `cz info`.
        """
        return "We use this because is useful"

The next file required is setup.py modified from flask version.

setup.py

from setuptools import setup

setup(
    name="JiraCommitizen",
    version="0.1.0",
    py_modules=["cz_jira"],
    license="MIT",
    long_description="this is a long description",
    install_requires=["commitizen"],
    entry_points={"commitizen.plugin": ["cz_jira = cz_jira:JiraCz"]},
)

So in the end, we would have

.
├── cz_jira.py
└── setup.py

And that's it. You can install it without uploading to PyPI by simply doing pip install .

Custom bump rules

You need to define 2 parameters inside your custom BaseCommitizen.

Parameter	Type	Default	Description
bump_pattern	str	None	Regex to extract information from commit (subject and body)
bump_map	dict	None	Dictionary mapping the extracted information to a SemVer increment type (MAJOR, MINOR, PATCH)

Let's see an example.

cz_strange.py

from commitizen.cz.base import BaseCommitizen


class StrangeCommitizen(BaseCommitizen):
    bump_pattern = r"^(break|new|fix|hotfix)"
    bump_map = {"break": "MAJOR", "new": "MINOR", "fix": "PATCH", "hotfix": "PATCH"}

That's it, your Commitizen now supports custom rules, and you can run.

cz -n cz_strange bump

Custom commit validation and error message

The commit message validation can be customized by overriding the validate_commit_message and format_error_message methods from BaseCommitizen. This allows for a more detailed feedback to the user where the error originates from.

import re
from commitizen.cz.base import BaseCommitizen, ValidationResult
from commitizen import git


class CustomValidationCz(BaseCommitizen):
    def validate_commit_message(
        self,
        *,
        commit_msg: str,
        pattern: str | None,
        allow_abort: bool,
        allowed_prefixes: list[str],
        max_msg_length: int,
    ) -> ValidationResult:
        """Validate commit message against the pattern."""
        if not commit_msg:
            return allow_abort, [] if allow_abort else [f"commit message is empty"]
        if pattern is None:
            return True, []
        if any(map(commit_msg.startswith, allowed_prefixes)):
            return True, []
        if max_msg_length:
            msg_len = len(commit_msg.partition("\n")[0].strip())
            if msg_len > max_msg_length:
                return False, [
                    f"commit message is too long. Max length is {max_msg_length}"
                ]
        pattern_match = re.match(pattern, commit_msg)
        if pattern_match:
            return True, []
        else:
            # Perform additional validation of the commit message format
            # and add custom error messages as needed
            return False, ["commit message does not match the pattern"]

    def format_exception_message(
        self, ill_formatted_commits: list[tuple[git.GitCommit, list]]
    ) -> str:
        """Format commit errors."""
        displayed_msgs_content = "\n".join(
            (
                f'commit "{commit.rev}": "{commit.message}"'
                f"errors:\n"
                "\n".join((f"- {error}" for error in errors))
            )
            for commit, errors in ill_formatted_commits
        )
        return (
            "commit validation: failed!\n"
            "please enter a commit message in the commitizen format.\n"
            f"{displayed_msgs_content}\n"
            f"pattern: {self.schema_pattern()}"
        )

Custom changelog generator

The changelog generator should just work in a very basic manner without touching anything. You can customize it of course, and the following variables are the ones you need to add to your custom BaseCommitizen.

Parameter	Type	Required	Description
commit_parser	str	NO	Regex which should provide the variables explained in the [changelog description][changelog-des]
changelog_pattern	str	NO	Regex to validate the commits, this is useful to skip commits that don't meet your ruling standards like a Merge. Usually the same as bump_pattern
change_type_map	dict	NO	Convert the title of the change type that will appear in the changelog, if a value is not found, the original will be provided
changelog_message_builder_hook	method: (dict, git.GitCommit) -> dict | list | None	NO	Customize with extra information your message output, like adding links, this function is executed per parsed commit. Each GitCommit contains the following attrs: rev, title, body, author, author_email. Returning a falsy value ignore the commit.
changelog_hook	method: (full_changelog: str, partial_changelog: Optional[str]) -> str	NO	Receives the whole and partial (if used incremental) changelog. Useful to send slack messages or notify a compliance department. Must return the full_changelog
changelog_release_hook	method: (release: dict, tag: git.GitTag) -> dict	NO	Receives each generated changelog release and its associated tag. Useful to enrich releases before they are rendered. Must return the update release

cz_strange.py

from commitizen.cz.base import BaseCommitizen
import chat
import compliance


class StrangeCommitizen(BaseCommitizen):
    changelog_pattern = r"^(break|new|fix|hotfix)"
    commit_parser = r"^(?P<change_type>feat|fix|refactor|perf|BREAKING CHANGE)(?:\((?P<scope>[^()\r\n]*)\)|\()?(?P<breaking>!)?:\s(?P<message>.*)?"
    change_type_map = {
        "feat": "Features",
        "fix": "Bug Fixes",
        "refactor": "Code Refactor",
        "perf": "Performance improvements",
    }

    def changelog_message_builder_hook(
        self, parsed_message: dict, commit: git.GitCommit
    ) -> dict | list | None:
        rev = commit.rev
        m = parsed_message["message"]
        parsed_message[
            "message"
        ] = f"{m} {rev} [{commit.author}]({commit.author_email})"
        return parsed_message

    def changelog_release_hook(self, release: dict, tag: git.GitTag) -> dict:
        release["author"] = tag.author
        return release

    def changelog_hook(
        self, full_changelog: str, partial_changelog: Optional[str]
    ) -> str:
        """Executed at the end of the changelog generation

        full_changelog: it's the output about to being written into the file
        partial_changelog: it's the new stuff, this is useful to send slack messages or
                           similar

        Return:
            the new updated full_changelog
        """
        if partial_changelog:
            chat.room("#committers").notify(partial_changelog)
        if full_changelog:
            compliance.send(full_changelog)
        full_changelog.replace(" fix ", " **fix** ")
        return full_changelog

Raise Customize Exception

If you want commitizen to catch your exception and print the message, you'll have to inherit CzException.

from commitizen.cz.exception import CzException


class NoSubjectProvidedException(CzException):
    ...

Migrating from legacy plugin format

Commitizen migrated to a new plugin format relying on importlib.metadata.EntryPoint. Migration should be straight-forward for legacy plugins:

• Remove the discover_this line from your plugin module
• Expose the plugin class under as a commitizen.plugin entrypoint.

The name of the plugin is now determined by the name of the entrypoint.

Example

If you were having a CzPlugin class in a cz_plugin.py module like this:

from commitizen.cz.base import BaseCommitizen


class PluginCz(BaseCommitizen):
    ...


discover_this = PluginCz

Then remove the discover_this line:

from commitizen.cz.base import BaseCommitizen


class PluginCz(BaseCommitizen):
    ...

and expose the class as entrypoint in your setuptools:

from setuptools import setup

setup(
    name="MyPlugin",
    version="0.1.0",
    py_modules=["cz_plugin"],
    entry_points={"commitizen.plugin": ["plugin = cz_plugin:PluginCz"]},
    ...,
)

Then your plugin will be available under the name plugin.