Cheat Sheets¶
Common commands and queries that you'll need often.
AWS CLI¶
# Confirm you're authenticated and as which user
aws sts get-caller-identity
# List ECS services in the cluster
aws ecs list-services --cluster platform-prod
# Get a shell on a running container
aws ecs execute-command \
--cluster platform-prod \
--task <task-arn> \
--container api \
--interactive \
--command "/bin/sh"
# Tail ECS logs
aws logs tail /ecs/platform-api --follow
Terraform¶
# Initialise after pulling
terraform init
# Show what will change
terraform plan
# Apply (after review)
terraform apply
# Show current state of one resource
terraform state show module.rds.aws_db_instance.this
# Import an existing resource into state
terraform import <address> <id>
PostgreSQL¶
-- List all tenant schemas
SELECT schema_name FROM information_schema.schemata
WHERE schema_name NOT IN ('public', 'pg_catalog', 'information_schema');
-- Switch to a tenant's schema for the session
SET search_path TO acme;
-- Find slow queries
SELECT query, mean_exec_time, calls
FROM pg_stat_statements
ORDER BY mean_exec_time DESC LIMIT 20;
-- Find missing indexes (large tables with sequential scans)
SELECT schemaname, tablename, seq_scan, seq_tup_read
FROM pg_stat_user_tables
WHERE seq_scan > 1000
ORDER BY seq_tup_read DESC;
Git¶
# Create a feature branch
git checkout -b feature/eng-123-description
# Amend the last commit
git commit --amend
# Interactive rebase to clean up commits before PR
git rebase -i main
# Pull with rebase (preferred over merge)
git pull --rebase
# See what's changed in a file across commits
git log --oneline --follow -- path/to/file
Docker¶
# Tail logs of all compose services
docker compose logs -f
# Reset everything (destroys local data)
docker compose down -v && docker compose up -d
# Shell into a running container
docker compose exec postgres bash
Python (uv)¶
# Install dependencies
uv pip install -e ".[dev]"
# Add a new dependency
# Edit pyproject.toml first, then:
uv pip install -e .
# Run tests
pytest
# Run tests with coverage
pytest --cov=src
# Run a specific test
pytest tests/modules/test_projects.py::test_create_project