Linter for jinja2

Every now and then, it's pretty useful to just have a cli tool that does the job. This does it.

Usage:

cp j2lint.py /usr/local/bin/
j2lint.py my-template.j2

It accepts multiple arguments so shell expansion and/or combining with find is no issue:

j2lint.py *.j2
find src -type f -name "*.j2" -exec j2lint.py '{}' +

Usage with custom filters, tests, etc

If you want to use this linter with custom filters, tests, etc, you can easily extend the main cli endpoint by passing in a env keyword argument.

The file custom_check_example.py provides a working example for the filter 'to_nice_json'.

Note that for linting it is not necessary to refer to the actual implementation of the filters, jinja2 only needs to know they exist.

Usage with docker

To run this using docker, run:

docker run --rm -v "$(pwd)":/check kaictl/j2lint

Important options:

-e CUSTOMLINT=path/to/custom/lint: the path to a custom lint py file in the directory you're checking. By default we check for /custom.py, so you can mount a file there instead of specifying this.
-v "$(pwd)":/check: mount the current directory to /check on the container

Usage with gitlab-ci

stages:
  - lint

jinja2-lint:
  image:
    name: tuxmartin/jinja2-lint:2022-05-24
    entrypoint: ["/bin/sh", "-c"]
  stage: lint
  script:
    - pwd
    - ls -lha templates/
    - >
      find templates/* \( -name '*' ! -iname ".*" \)
      -print0 | sort --zero-terminated | xargs -0 -I{} sh -c  '/usr/bin/python /j2lint.py {}'