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https://github.com/zavoloklom/docker-compose-linter

A command-line tool for validating and enforcing best practices in Docker Compose files.
https://github.com/zavoloklom/docker-compose-linter
dclint devops devops-tools docker docker-compose docker-compose-linter linter
Last synced: about 8 hours ago
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A command-line tool for validating and enforcing best practices in Docker Compose files.
Host: GitHub
URL: https://github.com/zavoloklom/docker-compose-linter
Owner: zavoloklom
License: mit
Created: 2024-08-21T20:45:51.000Z (5 months ago)
Default Branch: main
Last Pushed: 2025-01-01T15:18:55.000Z (9 days ago)
Last Synced: 2025-01-01T15:32:14.657Z (9 days ago)
Topics: dclint, devops, devops-tools, docker, docker-compose, docker-compose-linter, linter
Language: TypeScript
Homepage:
Size: 4.59 MB
Stars: 34
Watchers: 1
Forks: 4
Open Issues: 4
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Security: SECURITY.md
Awesome Lists containing this project

README

        


    

    


    Docker Compose Linter





    

    

    

    

    

    



> **Note**: Docker Compose configurations vary greatly between different projects and setups. While DCLint is stable,

> there may be edge cases or unique setups that cause issues. If you encounter any problems or have suggestions, please

> feel free to [open an issue](https://github.com/zavoloklom/docker-compose-linter/issues/new/choose) or

> [submit a pull request](#contributing). Your feedback is highly appreciated!

Docker Compose Linter (**DCLint**) is a utility designed to analyze, validate and fix Docker Compose files. It helps

identify errors, style violations, and potential issues in Docker Compose files, ensuring your configurations are

robust, maintainable, and free from common pitfalls.

## Features

- **Error Detection**: Identifies syntax errors and common issues in Docker Compose files.

- **Style Enforcement**: Enforces best practices and style guidelines for maintainable configurations.

- **Flexible Integration**: Can be used locally, in Docker, or integrated into CI/CD pipelines.

- **Configurable Rules**: Customize the linter's behavior and rules according to your project's needs.

- **Auto-fixable Rules**: Some rules include an auto-fix mode, allowing you to automatically format and correct certain

  issues in your files.

- **Comments Support**: After automated sorting and fixing, comments remain in the correct place, ensuring no important

  information is lost during the formatting process.

- **Anchor Support:** Supports YAML anchors for shared configuration sections, with

  [some limitations](#anchor-handling).

## Table of Contents

- [Usage with Node.js](#usage-with-nodejs)

- [Usage with Docker](#usage-with-docker)

- [Usage as a NPM Package](#usage-as-a-npm-package)

- [Rules and Errors](#rules-and-errors)

- [Configuration](#configuration)

- [Integration with CI/CD Pipeline](#integration-with-cicd-pipeline)

- [Alternatives](#alternatives)

- [Contributing](#contributing)

- [Contributors](#contributors)

- [Changelog](#changelog)

- [License](#license)

- [Contacts and Support](#contacts-and-support)

## Usage with Node.js

You can install Docker Compose Linter globally or use it directly with npx.

> **Note:** DCLint requires Node.js version 18 or higher.

To install it globally:

```shell

npm install --g dclint

```

And then run by command:

```shell

dclint .

```

If you prefer not to install it globally, you can run the linter directly using npx:

```shell

npx dclint .

```

This command will lint your Docker Compose files in the current directory.

### Linting Specific Files and Directories

To lint a specific Docker Compose file or a directory containing such files, specify the path relative to your project

directory:

```shell

npx dclint /path/to/docker-compose.yml

```

To lint all Docker Compose files in a specific directory, use the path to the directory:

```shell

npx dclint /path/to/directory

```

In this case, `dclint` will search the specified directory for files matching the following pattern

`/^(docker-)?compose.*\.ya?ml$/`.

It will handle all matching files within the directory and, if [recursive search](./docs/cli.md#-r---recursive) is

enabled, also in any subdirectories.

Files and directories like `node_modules`, `.git,` or others specified in the exclusion list will be ignored.

### Display Help and Options

To display help and see all available options:

```shell

npx dclint -h

```

For more details about available options and formatters, please refer to the [CLI Reference](./docs/cli.md) and

[Formatters Reference](./docs/formatters.md).

## Usage with Docker

### Pull the Docker Image

First, pull the Docker image from the repository:

```shell

docker pull zavoloklom/dclint

```

### Run the Linter in Docker

To lint your Docker Compose files, use the following command. This command mounts your current working directory

`${PWD}` to the `/app` directory inside the container and runs the linter:

```shell

docker run -t --rm -v ${PWD}:/app zavoloklom/dclint .

```

### Linting Specific Files and Directories in Docker

If you want to lint a specific Docker Compose file or a directory containing such files, specify the path relative to

your project directory:

```shell

docker run -t --rm -v ${PWD}:/app zavoloklom/dclint /app/path/to/docker-compose.yml

```

```shell

docker run -t --rm -v ${PWD}:/app zavoloklom/dclint /app/path/to/directory

```

### Display Help in Docker

To display help and see all available options:

```shell

docker run -t --rm -v ${PWD}:/app zavoloklom/dclint -h

```

For more information about available options and formatters, please refer to the [CLI Reference](./docs/cli.md) and

[Formatters Reference](./docs/formatters.md).

## Usage as a NPM Package

The `dclint` can be integrated directly into your JS code, allowing you to run linting checks programmatically and

format the results as desired. Below are examples of how to use `dclint` as a library in both CommonJS and ES module

formats.

First you need to install it:

```shell

npm install --save-dev dclint

```

### Example with CommonJS

```javascript

const { DCLinter } = require('dclint');

(async () => {

  const linter = new DCLinter();

  const lintResults = await linter.lintFiles(['.'], true);

  const formattedResults = await linter.formatResults(lintResults, 'stylish');

  console.log(formattedResults);

})();

```

### Example with ES Module

```javascript

import { DCLinter } from 'dclint';

const linter = new DCLinter();

const lintResults = await linter.lintFiles(['.'], true);

const formattedResults = await linter.formatResults(lintResults, 'stylish');

console.log(formattedResults);

```

## Rules and Errors

Docker Compose Linter includes set of rules to ensure your Docker Compose files adhere to best practices. Detailed

documentation for each rule and the errors that can be detected by the linter is available here:

- [Rules Documentation](./docs/rules.md)

- [Errors Documentation](./docs/errors.md)

DCLint uses the [yaml](https://github.com/eemeli/yaml) library for linting and formatting Docker Compose files. This

ensures that any configuration files you check are compliant with YAML standards. Before any rule checks are applied,

two important validations are performed, which cannot be disabled - [YAML Validity Check](./docs/errors/invalid-yaml.md)

and [Docker Compose Schema Validation](./docs/errors/invalid-schema.md).

### Disabling Rules via Comments

You can disable specific linting rules or all rules in your Docker Compose files using comments. These comments can be

used either to disable rules for the entire file or for individual lines. For detailed instructions on how to use these

comments, check out the full documentation here: [Using Configuration Comments](./docs/configuration-comments.md).

### Anchor Handling

Docker Compose Linter provides support for YAML anchors specifically during schema validation, which enables the reuse

of configuration sections across different services for cleaner and more maintainable files.

However, note that anchors are neither validated by individual linting rules nor automatically fixed when using the

`--fix` flag.

When multiple anchors are required in a Docker Compose file, use the following syntax:

```yaml

x-anchor1: &anchor1

  ports:

    - 80

x-anchor2: &anchor2

  ports:

    - 81

services:

  image: image

  <<: [ *anchor1, *anchor2 ]

```

This approach, which combines anchors in a single << line, is preferable to defining each anchor on separate lines (

e.g., `<< : *anchor1` followed by `<< : *anchor2`).

More information on YAML merge syntax is available in the

[official YAML documentation](https://yaml.org/type/merge.html) and in

[known issue with Docker Compose](https://github.com/docker/compose/issues/10411).

For an example of anchor usage, refer to the sample Compose file in `tests/mocks/docker-compose.anchors.yml`.

## Configuration

DCLint allows you to customize the set of rules used during linting to fit your project's specific needs. You can

configure which rules are applied, their severity levels, and additional behavior settings using a configuration file.

### Supported Configuration File Formats

DCLint supports flexible configuration options through the use of

[cosmiconfig](https://github.com/cosmiconfig/cosmiconfig). This means you can use various formats to configure the

linter, including JSON, YAML, and JavaScript files.

For example:

- `.dclintrc` (JSON, YAML, or JavaScript)

- `dclint.config.js` (JavaScript)

- A `dclint` key inside your `package.json`

### Example Configuration File

Here is an example of a configuration file using JSON format:

```json

{

  "rules": {

    "no-version-field": 0,

    "require-quotes-in-ports": 1,

    "services-alphabetical-order": 2

  },

  "quiet": false,

  "debug": true,

  "exclude": [

    "tests"

  ]

}

```

- **rules**: Customize which rules to apply and their severity levels (`0` - Disabled, `1` - Warning, `2` - Error).

- **quiet**: Suppresses non-error output if set to `true`.

- **debug**: Enables debug mode with additional output if set to `true`.

- **exclude**: Specifies files or directories to exclude from linting.

To enable editor autocompletion in a JSON configuration file, add a `$schema` property. If you have installed `dclint`:

```json

{

  "$schema": "./node_modules/dclint/schemas/linter-config.schema.json"

}

```

Otherwise:

```json

{

  "$schema": "https://raw.githubusercontent.com/zavoloklom/docker-compose-linter/refs/heads/main/schemas/linter-config.schema.json"

}

```

### Configure Rules

In addition to enabling or disabling rules, some rules may support custom parameters to tailor them to your specific

needs. For example, the [require-quotes-in-ports](./docs/rules/require-quotes-in-ports-rule.md) rule allows you to

configure whether single or double quotes should be used around port numbers. You can configure it like this:

```json

{

  "rules": {

    "require-quotes-in-ports": [

      2,

      {

        "quoteType": "double"

      }

    ]

  }

}

```

In this example, the require-quotes-in-ports rule is enabled at the error level and configured to enforce double quotes

around ports.

## Integration with CI/CD Pipeline

Automate linting as part of your CI/CD pipeline by adding the Docker run command to your pipeline script. This ensures

that your Docker Compose files are always checked for errors before deployment.

### GitLab CI Example

```yaml

lint-docker-compose:

  image:

    name: zavoloklom/dclint:alpine

    entrypoint: [ '' ]

  script:

    - /bin/dclint . -r -f codeclimate -o gl-codequality.json

  artifacts:

    reports:

      codequality: gl-codequality.json

```

## Alternatives

Consider these alternative tools for Docker Compose linting and validation:

- [kics](https://github.com/Checkmarx/kics)

- [yamllint](https://github.com/adrienverge/yamllint)

And this tools for Docker Compose formatting and fixing:

- [compose_format](https://github.com/funkwerk/compose_format/)

- [yamlfix](https://github.com/lyz-code/yamlfix)

## Contributing

If you encounter any issues or have suggestions for improvements, feel free to open an

[issue](https://github.com/zavoloklom/docker-compose-linter/issues) or submit a

[pull request](https://github.com/zavoloklom/docker-compose-linter/pulls).

If you'd like to contribute to this project, please read through the [CONTRIBUTING.md](./CONTRIBUTING.md) file.

Please note that this project is released with a [Contributor Code of Conduct](./CODE_OF_CONDUCT.md). By participating

in this project, you agree to abide by its terms.

- [How to set up the project](./CONTRIBUTING.md)

- [How to add a new rule](./CONTRIBUTING.md#how-to-add-a-new-rule)

## Contributors

Thanks goes to these wonderful people ([emoji keys explanation](https://allcontributors.org/docs/en/emoji-key)):

  

    

      
_{Szymon Filipiak}
💻

      
_{Ben Rexin}
💻 📖 ⚠️

      
_{Ádám Liszkai}
💡

      
_{Adam Vigneaux}
💻 📖

    

  

This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification.

Contributions of any kind welcome!

## Changelog

The changelog is automatically generated based on

[semantic-release](https://github.com/semantic-release/semantic-release) and

[conventional commits](https://www.conventionalcommits.org/en/v1.0.0/).

See the [CHANGELOG.md](./CHANGELOG.md) file for detailed lists of changes for each version.

## License

This project is licensed under the MIT License. See the [LICENSE](./LICENSE) file for more information.

## Contacts and Support

If you find this repository helpful, kindly consider showing your appreciation by giving it a star ⭐.

If you have any questions or suggestions, feel free to reach out:

- **Email**: [[email protected]](mailto:[email protected])

- **Х/Twitter**: [zavoloklom](https://x.com/zavoloklom)

- **Instagram**: [zavoloklom](https://www.instagram.com/zavoloklom/)

- **GitHub**: [zavoloklom](https://github.com/zavoloklom)

Also, you can support this project with a donation:

[![PayPal](https://img.shields.io/badge/PayPal-00457C?style=for-the-badge&logo=paypal&logoColor=white)](https://www.paypal.com/donate/?hosted_button_id=ZKLT8EJ4KWA6L)

[![BuyMeACoffee](https://img.shields.io/badge/Buy%20Me%20a%20Coffee-ffdd00?style=for-the-badge&logo=buy-me-a-coffee&logoColor=black)](https://www.buymeacoffee.com/zavoloklom)