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Dockerignore

2 snippets in Docker

DKDocker

.dockerignore - Exclude Build Context

DK · Dockerfile
Syntax
# .dockerignore file
pattern
dir/
Example
node_modules
.git
*.md
.env
dist
.DS_Store
coverage

Note Place this file next to your Dockerfile. Without it, Docker sends everything in the build context to the daemon, including node_modules (hundreds of MB), .git history, and possibly secrets in .env files. This is one of the highest-impact optimizations you can make.

Always Use .dockerignore

DK · Best Practices
Syntax
# .dockerignore
Example
node_modules
.git
*.md
.env*
coverage
dist
.DS_Store
__pycache__
*.pyc
.venv

Note Without .dockerignore, a COPY . . sends everything to the daemon including .git (often 100MB+), node_modules, environment files with secrets, and test coverage reports. Builds become slow and images become bloated.

Frequently asked questions

How does Docker handle dockerignore?
Docker covers this with 2 copy-ready snippets on this page. The ".dockerignore - Exclude Build Context" snippet in Docker uses `# .dockerignore file`.
Which command does the Docker example use?
The ".dockerignore - Exclude Build Context" snippet uses `# .dockerignore file`, from the Dockerfile section of the Docker cheat sheet.
What other Docker snippets are shown for "dockerignore"?
Besides ".dockerignore - Exclude Build Context", this page also shows "Always Use .dockerignore".
Is there anything to watch out for?
Yes. For ".dockerignore - Exclude Build Context": Place this file next to your Dockerfile. Without it, Docker sends everything in the build context to the daemon, including node_modules (hundreds of MB), .git history, and possibly secrets in .env files. This is one of the highest-impact optimizations you can make.

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