docker-compose-exec

name	docker-compose-exec
description	Run commands inside Docker Compose services. Use when services are only reachable from inside compose networks.

When to Use

• Accessing services only available within Docker Compose network (databases, APIs, etc.)
• Running CLI tools that exist only inside a compose service container
• Debugging compose service networking or internal state
• Executing migrations, seeds, or admin commands in compose services

Workflow

1. Identify the Target Service

First, determine which service to use:

docker compose ps

Look for:

• A running service with the required tools/access
• The service name from docker-compose.yml

2. Choose Execution Method

If service is already running → Use docker compose exec If service is not running → Use docker compose run --rm

3. Execute the Command

Option A: Running Service (docker compose exec)

docker compose exec <service_name> <command>

For interactive commands, add -it (or omit if compose defaults are fine):

docker compose exec -it <service_name> <command>

Examples:

# Run psql in a running postgres service
docker compose exec db psql -U myuser -d mydb

# Run a Rails migration
docker compose exec web rails db:migrate

# Check connectivity from inside service
docker compose exec web curl -s http://internal-service:3000/health

Option B: No Running Service (docker compose run --rm)

docker compose run --rm <service_name> <command>

Examples:

# Run psql against a database in the compose network
docker compose run --rm db psql -U myuser -d mydb

# Run a one-off script with volumes and env set by compose
docker compose run --rm app python /app/script.py

4. Compose Project Context

Run commands from the directory with docker-compose.yml or specify:

docker compose -f /path/to/docker-compose.yml ps

Common Patterns

Database Access

# PostgreSQL - running service
docker compose exec db psql -U postgres -d mydb -c "SELECT * FROM users LIMIT 5;"

# PostgreSQL - no running service
docker compose run --rm db psql -U postgres -d mydb

# MySQL - running service
docker compose exec mysql mysql -u root -p mydb

# Redis - running service
docker compose exec redis redis-cli KEYS '*'

Running Migrations/Seeds

# Rails
docker compose exec web rails db:migrate
docker compose exec web rails db:seed

# Django
docker compose exec web python manage.py migrate
docker compose exec web python manage.py loaddata fixtures.json

# Node.js (Prisma)
docker compose exec web npx prisma migrate deploy

Debugging Network Issues

# Check DNS resolution inside service
docker compose exec web nslookup service_name

# Test connectivity to internal service
docker compose exec web curl -v http://internal-api:8080/health

# Check what ports are listening
docker compose exec web netstat -tlnp

Interactive Shell

# Get a shell in running service
docker compose exec web /bin/sh
docker compose exec web /bin/bash

# Get a shell in fresh service container
docker compose run --rm web /bin/sh

Flags Reference

Flag	Purpose
-it	Interactive terminal (use for shells, psql, etc.)
--rm	Remove container after exit (for docker compose run)
-e VAR=value	Set environment variable (run only)
-v host:container	Mount volume (run only)
-w /path	Set working directory
--user uid:gid	Run as specific user

Troubleshooting

"Service not found": Check service name with docker compose ps

"Compose file not found": Run from directory containing docker-compose.yml or pass -f

"Command not found": The tool may not be installed in that service. Try a different service or add it to the image.

Permission denied: Try adding --user root or check volume mount permissions