We are using the [Hadolint][LK1] tool to analyse each `Dockerfile` to comply with [Docker best practices][LK2].
## Install
There is a specific make target to install the linter.
By default `hadolint` will be installed in `${HOME}/hadolint`.
```bash
$ make lint-install
# Installing hadolint at /Users/romain/hadolint ...
# Installation done!
# Haskell Dockerfile Linter v1.17.6-0-gc918759
```
## Lint
The linter can be run per stack `make lint/<stack>`
```bash
$ make lint/scipy-notebook
# Linting Dockerfiles in scipy-notebook...
# scipy-notebook/Dockerfile:4 DL3006 Always tag the version of an image explicitly
# scipy-notebook/Dockerfile:11 DL3008 Pin versions in apt get install. Instead of `apt-get install <package>` use `apt-get install <package>=<version>`
# scipy-notebook/Dockerfile:18 SC2086 Double quote to prevent globbing and word splitting.
# scipy-notebook/Dockerfile:68 SC2086 Double quote to prevent globbing and word splitting.
# scipy-notebook/Dockerfile:68 DL3003 Use WORKDIR to switch to a directory
# scipy-notebook/Dockerfile:79 SC2086 Double quote to prevent globbing and word splitting.
# make: *** [lint/scipy-notebook] Error 1
```
Optionally you can pass arguments to the linter.
```bash
# Use a different export format
$ make lint/scipy-notebook ARGS="--format codeclimate"
```
To lint all the stacks.
```bash
$ make lint-all
```
## Ignore Rules
Sometimes it's necessary to ignore [some rules][LK3]. The preferred way is to do it in the `Dockerfile`.
> It is also possible to ignore rules by using a special comment directly above the Dockerfile instruction you want to make an exception for. Ignore rule comments look like `# hadolint ignore=DL3001,SC1081.` For example:
