Build context

2 snippets in Docker

DKDocker

.dockerignore — Exclude Build Context

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.

Build Configuration

DK · Docker Compose

syntax

services:
  api:
    build:
      context: <path>
      dockerfile: <file>
      args:
        KEY: value

example

services:
  api:
    build:
      context: .
      dockerfile: docker/Dockerfile.prod
      args:
        NODE_VERSION: 20
    image: myapp:latest

Note Setting both build and image means Compose builds and tags the result with that image name. The context path is relative to the compose file location.