Docker Compose

Two approaches for injecting secrets into Docker Compose services.

Approach 1: Wrap the Command (Recommended)

Run docker compose under skret run -- so all secrets are available as environment variables:

skret run -- docker compose up -d

Docker Compose inherits the environment from its parent process. Secrets set by skret run are passed to containers via the environment directive in docker-compose.yml:

services:
  app:
    image: myapp:latest
    environment:
      - DATABASE_URL
      - REDIS_URL
      - API_KEY

Each listed variable is forwarded from the host environment (set by skret) into the container. This is the cleanest approach -- no .env file on disk.

With Makefile

up-app:
	skret run -- docker compose up -d app

down-app:
	docker compose down app

logs:
	docker compose logs -f app

Approach 2: Generate .env File

For tools or workflows that require a .env file:

skret env > .env
docker compose up -d

Reference in docker-compose.yml:

services:
  app:
    image: myapp:latest
    env_file:
      - .env

Drawbacks:

• Secrets written to disk (even temporarily)
• Must regenerate .env when secrets change
• Must ensure .env is in .gitignore

Atomic Update Pattern

If you must use .env, regenerate it before each start:

up-app:
	skret env > .env
	docker compose up -d app
	rm -f .env

down-app:
	docker compose down app

Approach Comparison

Aspect	skret run --	skret env > .env
Secrets on disk	No	Yes (temporary)
Auto-updates	Yes (fetched each run)	No (manual regenerate)
Works offline	Only with local provider	Yes, once generated
Docker Compose version	Any	Any
CI/CD friendly	Yes	Yes

Multi-Environment

# Start staging services
skret --env=staging run -- docker compose -f docker-compose.yml -f docker-compose.staging.yml up -d

# Start production services
skret --env=prod run -- docker compose -f docker-compose.yml -f docker-compose.prod.yml up -d

Migrating from .env

If you currently use .env files with Docker Compose:

# 1. Import existing .env into skret
skret import --from=dotenv --file=.env

# 2. Verify secrets were imported
skret list

# 3. Switch docker-compose.yml from env_file to environment
# Before:
#   env_file: .env
# After:
#   environment:
#     - DATABASE_URL
#     - REDIS_URL

# 4. Run with skret
skret run -- docker compose up -d

# 5. Remove .env once confirmed
rm .env