How to make docker wait for SQL script inside /docker-entrypoint-initdb.d to be executed

Question

I am dockerizing an application with two services in docker-compose.yml: a web image build from php:7.3.28-apache and a database image build from postgres:11.12-alpine. Inside database Dockerfile I am executing a sql file to populate the database by doing:

COPY ./dump.sql /docker-entrypoint-initdb.d/

In my web image I do a migration. But the migration should only occur after the database end executing the sql file. So I use the wait-for-it.sh script to wait for the database port to be available:

CMD composer install ; wait-for-it -t 0 db:5432 -- bin/console doctrine:migrations:migrate ; apache2-foreground

The problem is that the port db:5432 becomes available before dump.sql file end execution.

I already tried

depends_on:
    - db

in docker-compose.yml and the problem persists. Is there a way to lock the port db:5432 until dump is done, or a way to make web service to wait for the end of dump execution in db service?

The sql file is executing nicely in database, so the populating step is ok. My problem is that I would like to make the migration only after "retoring" the dump file. Since the migration command called in the web service, I would like to make the web service somehow wait for db service. I was thinking in using sleep in web service, but it does not seems a neat solution. — Lilia Martins
– Lilia Martins, Commented May 26, 2021 at 18:11

Akshay Hegde · Accepted Answer · 2021-05-27 14:02:55Z

1

Solution is to utilise HEALTHCHECK [OPTIONS] CMD command

The command after the CMD keyword can be either a shell command (e.g. HEALTHCHECK CMD /bin/check-running) or an exec array (as with other Dockerfile commands; see e.g. ENTRYPOINT for details).

The command’s exit status indicates the health status of the container. The possible values are:

0: success - the container is healthy and ready for use

1: unhealthy - the container is not working correctly

2: reserved - do not use this exit code

Probably you can create some shell script

#!/bin/sh

# if your last table exists we assume may be 
# we are now ready for migration 
# put whatever logic you have to ensure data import was successful

# if file exits then exit code 0 else exit code 1
[ -f  "/path/to/my/last/table" ] && exit 0 || exit 1

In docker-compose.yml you need

depends_on:
      database:
           condition: service_healthy

edited May 27, 2021 at 14:02

answered May 27, 2021 at 3:15

Akshay Hegde

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