Live Docker health check

live_docker_health_check.sh

# If you have a healthcheck defined in your Dockerfile
# 
# HEALTHCHECK --interval=5s --timeout=4s --start-period=10s CMD-SHELL pg_isready -U postgres -t 0 || exit 1
# 
# or in your docker-compose.yml
#
# healthcheck:
#   test: ["CMD-SHELL", "pg_isready -U postgres -t 0 || exit 1"]
#   timeout: 4s
#   interval: 5s
#   start_period: 10s
#
# You can view the result of those checks in the docker inspect json output. You can filter it out with jq.
# I like to watch it live as the container starts up when I'm working on a new setup, to see if I tuned the timing parameters correctly.

watch -n1 "docker inspect compose_postgres_1 2>/dev/null | jq '.[0].State.Health' 2>/dev/null"