What is .dockerignore?
Excludes files from build context, similar to .gitignore.
Example .dockerignore
# Git
.git
.gitignore
# Dependencies
node_modules
vendor/bundle
# Logs
*.log
log/
# Temp files
tmp/
.cache/
# IDE
.idea/
.vscode/
# Docker
Dockerfile*
docker-compose*
.docker/
# Environment
.env*
!.env.example
# Test
coverage/
spec/
test/
# Documentation
README.md
docs/
Benefits
- Faster builds
- Smaller context sent to Docker daemon
- Prevents sensitive files from being included
Rails .dockerignore
.git
.gitignore
node_modules
tmp/
log/
storage/
.env*
docker-compose*
Dockerfile*
spec/
test/
coverage/
.rspec