The tutorial skips over a few things, and is confusing in that it mentions the wait-for-it.sh script, but then shows a much simplified version that doesn't work if you pass hostname:port as one argument to it.
I had a crack at getting this to work and both for future me and others I will add the steps below. I did this on MacOS, and have both docker and docker-compose installed as well as nodejs.
I don't have your node app handy so I used the one as described here https://nodejs.org/de/docs/guides/nodejs-docker-webapp/
I have the following directory structure:
/src/package.json
/src/server.js
/.pgpass
/docker-compose.yml
/Dockerfile
/wait-for-postgres.sh
The contents of these files is listed below.
Steps
- From the
./src directory run $ npm install (creates package-lock.json)
- Fix pgpass permissions with
$ chmod 600 .pgpass
- Make the script executable
$ chmod +x wait-for-postgres.sh
- From the root directory
$ docker-compose up
It will pull the postgres image and build the node app container.
When that's done it will wait for postgres and when postgres is up you'll see it ready.
Files
The src files are exactly as per the node js dockerize link above
/src/package.json
{
"name": "docker_web_app",
"version": "1.0.0",
"description": "Node.js on Docker",
"author": "First Last <first.last@example.com>",
"main": "server.js",
"scripts": {
"start": "node server.js"
},
"dependencies": {
"express": "^4.16.1"
}
}
/src/server.js
'use strict';
const express = require('express');
// Constants
const PORT = 8080;
const HOST = '0.0.0.0';
// App
const app = express();
app.get('/', (req, res) => {
res.send('Hello world\n');
});
app.listen(PORT, HOST);
console.log(`Running on http://${HOST}:${PORT}`);
.pgpass
This uses the username:password postgres:postgres and is purely for development demo purposes. In the wild you will use some other method of secrets management and never ever commit a pgpass file to version control
#host:port:db:user:pass
db:5432:*:postgres:postgres
docker-compose.yml
- I have added the
wait-for-postgres.sh script as a managed volume, in the original question it was bundling it in with the app src which was weird.
I have also mounted the .pgpass file in the root user's home directory, which psql will look in for auto-password completion. If you don't have some method of supplying this then you'll get an error:
psql: fe_sendauth: no password supplied
Notice the command for the server container is referring to database which is a valid docker-compose internal dns name for the postgres container.
version: '2'
services:
server:
build: .
ports:
- 3030:3030
depends_on:
- database
volumes:
- ./wait-for-postgres.sh:/usr/app/setup/wait-for-postgres.sh
- ./.pgpass:/Users/root/.pgpass
command: ["/usr/app/setup/wait-for-postgres.sh", "database", "--", "node", "src"]
database:
image: postgres
environment:
- "POSTGRES_USER=postgres"
- "POSTGRES_PASSWORD=postgres"
- "POSTGRES_DB=tide_server"
ports:
- 5432:5432
Dockerfile
- I have modified this from the node js tutorial, pinning it to the Debian "buster" version and also installing
psql which it needs for that script.
FROM node:10-buster
RUN apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys B97B0AFCAA1A47F044F244A07FCC7D46ACCC4CF8
RUN echo "deb http://apt.postgresql.org/pub/repos/apt/ buster-pgdg main" > /etc/apt/sources.list.d/pgdg.list && \
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
RUN apt-get -y update - && \
apt-get -y install libpq-dev && \
apt-get -y install postgresql-client-11
# Create app directory
WORKDIR /usr/src/app
# Install app dependencies
# A wildcard is used to ensure both package.json AND package-lock.json are copied
# where available (npm@5+)
COPY package*.json ./
RUN npm install
# If you are building your code for production
# RUN npm ci --only=production
# Bundle app source
COPY . .
EXPOSE 8080
CMD [ "node", "server.js" ]
wait-for-postgres.sh
- I have modified the script very slightly because I ran the "shellcheck" linter and it complained about a few things. I realise this script is from the docker tutorial page.
#!/bin/bash
# wait-for-postgres.sh
set -e
host="$1"
shift
cmd="$*"
export PGPASSFILE=./pgpass
until psql -h "$host" -U "postgres" -c '\l'; do
>&2 echo "Postgres is unavailable - sleeping"
sleep 1
done
>&2 echo "Postgres is up - executing command"
exec "$cmd"
