.dockerignore generator

How to use it

1. Leave Docker and Git files and Secrets ticked: they are useful in almost every project.
2. Tick your language and, if needed, editors and OS files.
3. Add your own patterns, for example a folder of test fixtures.
4. Save the result as .dockerignore in the build context root, usually next to the Dockerfile.

How it works

The chosen lists are combined in a fixed order: Docker and Git, secrets, languages, editors, OS files, then your own patterns. A pattern that already appeared in an earlier group is not repeated, and a group left empty by that is dropped.

Docker matches each line against paths relative to the context root. * matches within one folder, ** matches any number of folders, and ! re-includes files excluded before.

Example

The default choice (Docker and Git, secrets, Node.js, OS files) starts like this:

# Docker and Git
.git
.gitignore
.dockerignore
Dockerfile*
docker-compose*.yml
compose*.yaml
**/*.log

# Secrets
.env
.env.*
!.env.example
**/*.pem
**/*.key

and goes on with **/node_modules, npm and pnpm logs, coverage, dist, **/.DS_Store and **/Thumbs.db.

Tips

• Excluding node_modules matters for more than speed: dependencies installed on your machine may be built for another system. Install them inside the image instead.
• If your Dockerfile copies a prebuilt file, such as target/app.jar or dist/, untick that group or add an exception with !.
• Run docker build --no-cache . after big changes to check that the image still builds without the ignored files.