Docker cannot establish connection with postgresql in Travis CI

Question

I'm trying to integrate Travis CI into my rails app. Everything works fine on my local machine(ubuntu, windows), but on travis host there is a connection error. So, here are my configurations.

.travis.yml:

sudo: required

language: ruby

services:
  - docker

env:
  DOCKER_COMPOSE_VERSION: 1.13.0

before_install:
  - sudo rm /usr/local/bin/docker-compose
  - curl -L https://github.com/docker/compose/releases/download/${DOCKER_COMPOSE_VERSION}/docker-compose-`uname -s`-`uname -m` > docker-compose
  - chmod +x docker-compose
  - sudo mv docker-compose /usr/local/bin
  - sudo apt-get update
  - sudo apt-get -y -o Dpkg::Options::="--force-confnew" install docker-engine
  - docker-compose build
  - docker-compose -f docker-compose.commands.yml run --rm website rails db:create db:migrate db:test:prepare

script:
 - docker-compose -f docker-compose.commands.yml run --rm -e RAILS_ENV=test website rspec

database.yml:

development: &default
adapter: postgresql
database: my_app_development
username: postgres
host: postgres
port: 5432

docker-compose.commands.yml:

version: '3'

services:
  postgres:
    image: 'postgres:9.6.2'
    ports:
      - "5432"

  website:
    depends_on:
      - 'postgres'
    build: .
    ports:
      - '3000'
  volumes:
    - '.:/my_app'
    - 'bundle_data:/bundle'

 volumes:
  bundle_data:

But travis log outputs this when it runs migrations

Status: Downloaded newer image for postgres:9.6.2

Creating myapp_postgres_1 ...

Creating myapp_postgres_1

could not connect to server: Connection refused Is the server running on host "postgres" (172.18.0.2) and accepting TCP/IP connections on port 5432? Couldn't create database for {"adapter"=>"postgresql", "encoding"=>"unicode", "database"=>"my_app_development", "pool"=>5, "username"=>"postgres", "host"=>"postgres", "port"=>5432} rails aborted! PG::ConnectionBad: could not connect to server: Connection refused Is the server running on host "postgres" (172.18.0.2) and accepting TCP/IP connections on port 5432?

Likely a timing issue. depends_on does not wait for postgres to be ready, just for the container to start. Look at using something like wait-for-it.sh to wait for postgres to be up before connecting to it. — johnharris85
I don't see anything in the extra log that changes my opinion? — johnharris85
the error occures after database container was created. Doesn't that mean that database is ready? — Slava Nikulin
No, like I said, container created != postgres ready to accept connections. — johnharris85

Slava Nikulin Slava Nikulin · Accepted Answer · 2017-05-11T03:21:56

Thanks to @johnharris85 and @jbielick I've found this solution:

website:
    depends_on:
      - 'postgres'
    build: .
    ports:
      - '3000'
    volumes:
      - '.:/my_app'
      - 'bundle_data:/bundle'
    entrypoint: ./wait-for-postgres.sh postgres 5432

  postgres:
    image: 'postgres:9.6.2'
    ports:
      - '5432'

wait-for-postgres.sh:

#!/bin/sh

postgres_host=$1
postgres_port=$2
shift 2
cmd="$@"

# wait for the postgres docker to be running
while ! pg_isready -h $postgres_host -p $postgres_port -q -U postgres; do
  >&2 echo "Postgres is unavailable - sleeping"
  sleep 1
done

>&2 echo "Postgres is up - executing command"

# run the command
exec $cmd

Docker cannot establish connection with postgresql in Travis CI

1 Answers