DockClean

DockClean is a Go-based tool designed to clean up unused Docker images, enhancing storage management with options like size limits, verbose mode, and concurrent deletion.

Features

• List and remove unused Docker images (images without tags)
• Clean images exceeding a specified size limit
• Option to remove images associated with stopped containers
• Verbose mode for detailed output
• Concurrent deletion for faster cleanup

Prerequisites

• Install Go: https://go.dev/dl/

• Optional: For testing the application, you can generate a set of unused Docker images with predefined scripts. These scripts will create several untagged images, which can be cleaned by DockClean after each run.

  • Place a Dockerfile in the project directory.

  • Use the following scripts to create multiple unlabelled images:

    • Windows (PowerShell):

      .\scripts\test\generate-unused-images.ps1

    • Linux (Bash):

      ./scripts/test/generate-unused-images.sh

Installation

1. Clone the repository:

   git clone https://github.com/mmuazam98/dockclean.git
   cd dockclean

2. Install dependencies:

   go mod tidy

3. Build the binary:

   go build -o dockclean ./cmd/cleaner
   # On Windows Run
   go build -o dockclean.exe ./cmd/cleaner

Usage

Once the binary is built, you can use DockClean to clean up your Docker images.

1. Basic Command

To list and remove unused Docker images sequentially:

./dockclean
# On Windows Run
dockclean.exe

This command will:

• Connect to the Docker daemon.
• List all unused (untagged) images.
• Remove these images in a sequential order.

Sample Output (Sequential Execution):

• Execution Time: 611 ms
  

2. Enabling Concurrent Deletion

To remove images concurrently (using Go routines for faster cleanup), add the --concurrent flag. This flag enables DockClean to remove images in parallel, resulting in quicker execution times compared to sequential deletion.

Example:

./dockclean --concurrent
# On Windows Run
dockclean.exe --concurrent

Sample Output (Concurrent Execution):

• Execution Time: 143 ms
  

Command-Line Options

3. --dry-run : List unused images without deleting them.

Example:

./dockclean --dry-run
# On Windows Run
dockclean.exe --dry-run

This option will show which images would be deleted without performing any actual deletion.

4. --remove-stopped : Remove images associated with stopped containers.

Example:

./dockclean --remove-stopped
# On Windows Run
dockclean.exe --remove-stopped

This command removes Docker images that are only associated with stopped containers, freeing up space from unused images.

Sample Output:

5. --verbose : Enable detailed output for each image during cleanup.

Example:

./dockclean --verbose
# On Windows Run
dockclean.exe --verbose

Verbose mode provides additional details about each image, such as its size and creation date, making it easier to see what’s being deleted.

Sample Output:

6. --size-limit <value> : Set a size threshold for deleting images (e.g., --size-limit 500MB).

• Specify units with --B, --KB, --MB, or --GB.

Example:

./dockclean --size-limit 500MB
# On Windows Run
dockclean.exe --size-limit 500MB

This command will only delete images that exceed the specified size limit.

Sample Output:

Extending DockClean

You can extend DockClean’s functionality by adding features like:

• Filtering: Clean images based on additional criteria such as age.
• Interactive mode: Prompt for confirmation before deletion.

Contributing

Feel free to open an issue or submit a pull request if you:

• Find bugs
• Have feature suggestions
• Want to improve code quality or documentation

License

This project is licensed under the MIT License. See the LICENSE file for details.