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Tool to check generic rules/best-practices for containers/images/dockerfiles.

Project description

# Colin

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Tool to check generic rules and best-practices for container images and dockerfiles.

For more information, please check our [documentation on](


# Features

* Validate a selected artifact against a ruleset.
* Artifacts can be container images and dockerfiles.
* We provide a default ruleset we believe every container image should satisfy.
* There is a ruleset to validate an artifact whether it complies to [Fedora Container Guidelines](
* Colin can list available rulesets and list checks in a ruleset.
* There is a python API available
* Colin can be integrated into your workflow easily - it can provide results in json format.

## Installation

### Via `pip`

If you are on Fedora distribution, please install python3-pyxattr so you don't
have to compile it yourself when getting it from PyPI.

$ pip3 install --user colin

### On Fedora distribution

colin is packaged in official Fedora repositories:
$ dnf install -y colin

### Requirements

- For checking `image` target-type, you have to install [podman](
If you need to check local docker images, you need to prefix your images with `docker-daemon` (e.g. `colin check`).

- If you want to use `ostree` target, you need to install following tools:
- [ostree](
- [atomic](
- [skopeo](

## Usage

$ colin --help
Usage: colin [OPTIONS] COMMAND [ARGS]...

COLIN -- Container Linter

-V, --version Show the version and exit.
-h, --help Show this message and exit.

check Check the image/dockerfile (default).
info Show info about colin and its dependencies.
list-checks Print the checks.
list-rulesets List available rulesets.

$ colin check --help
Usage: colin check [OPTIONS] TARGET

Check the image/dockerfile (default).

-r, --ruleset TEXT Select a predefined ruleset (e.g. fedora).
-f, --ruleset-file FILENAME Path to a file to use for validation (by
default they are placed in
--debug Enable debugging mode (debugging logs, full
--json FILENAME File to save the output as json to.
--stat Print statistics instead of full results.
-s, --skip TEXT Name of the check to skip. (this option is
-t, --tag TEXT Filter checks with the tag.
-v, --verbose Verbose mode.
--checks-path DIRECTORY Path to directory containing checks (default
--pull Pull the image from registry.
--target-type TEXT Type of selected target (one of image,
dockerfile, ostree). For ostree, please specify
image name and path like this: image@path
--timeout INTEGER Timeout for each check in seconds.
--insecure Pull from an insecure registry (HTTP or invalid
-h, --help Show this message and exit.

Let's give it a shot:
$ colin -f ./rulesets/fedora.json
PASS:Label 'architecture' has to be specified.
PASS:Label 'build-date' has to be specified.
FAIL:Label 'description' has to be specified.
PASS:Label 'distribution-scope' has to be specified.

### Directly from git

It's possible to use colin directly from git:

$ git clone
$ cd colin

We can now run the analysis:

$ python3 -m colin.cli.colin -f ./rulesets/fedora.json
PASS:Label 'architecture' has to be specified.
PASS:Label 'build-date' has to be specified.
FAIL:Label 'description' has to be specified.
PASS:Label 'distribution-scope' has to be specified.

### Exit codes

Colin can exit with several codes:

- `0` --> OK
- `1` --> error in the execution
- `2` --> CLI error, wrong parameters
- `3` --> at least one check failed

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