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up vote 14 down vote favorite
5

I have been trying to set up a container for a development postgres instance by creating a custom user & database. I am using the official postgres docker image. In the documentation it instructs you to insert a bash script inside of the /docker-entrypoint-initdb.d/ folder to set up the database with any custom parameters.

My bash script: make_db.sh

su postgres -c "createuser -w -d -r -s docker"
su postgres -c "createdb -O docker docker"

Dockerfile

FROM library/postgres

RUN ["mkdir", "/docker-entrypoint-initdb.d"]
ADD make_db.sh /docker-entrypoint-initdb.d/

The error I get from the docker logs -f db (db is my container name) is:

createuser: could not connect to database postgres: could not connect to server: No such file or directory

It seems that the commands inside of the /docker-entrypoint-initdb.d/ folder are being executed before postgres is started. My question is, how do I set up a user/database programmatically using the official postgres container? Is there any way to do this with a script?

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3 Answers 3

up vote 16 down vote accepted

From the documentation of the postgres Docker image, it is said that

[...] it will source any *.sh script found in that directory [/docker-entrypoint-initdb.d] to do further initialization before starting the service

What's important here is "before starting the service". This means your script make_db.sh will be executed before the postgres service would be started, hence the error message "could not connect to database postgres".

After that there is another useful piece of information:

If you need to execute SQL commands as part of your initialization, the use of Postgres single user mode is highly recommended.

Agreed this can be a bit mysterious at the first look. What it says is that your initialization script should start the postgres service in single mode before doing its actions. So you could change your make_db.ksh script as follow and it should get you closer to what you want:

gosu postgres postgres --single <<- EOSQL
    CREATE USER docker;
    CREATE DATABASE docker;
    GRANT ALL PRIVILEGES ON DATABASE docker TO docker;
EOSQL
share|improve this answer
    
Worked perfectly. Thank you. I guess I just didn't understand the purpose of single user mode before. Interesting feature! –  and_it_is_ten Oct 28 '14 at 12:44
    
Is there a way to run an sql file in single user mode –  DarVar Jan 6 at 17:05
1  
you can with: gosu postgres postgres --single < /tmp/somefile.sql –  Thomasleveil Jan 6 at 17:06
    
How can I run psql -U myDb -d myDb -f myDb.sql –  DarVar Jan 6 at 17:38
up vote 0 down vote

I add custom commands to a environment evoked in a CMD after starting services... I haven't done it with postgres, but with Oracle:

#set up var with noop command
RUN export POST_START_CMDS=":"
RUN mkdir /scripts
ADD script.sql /scripts
CMD service oracle-xe start; $POST_START_CMDS; tail -f /var/log/dmesg

and start with 

docker run -d ... -e POST_START_CMDS="su - oracle -c 'sqlplus @/scripts/script' " <image>

.

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up vote 1 down vote

You need to have the database running before you create the users. For this you need multiple processes. You can either start postgres in a subshell (&) in the shell script, or use a tool like supervisord to run postgres and then run any initialization scripts.

A guide to supervisord and docker https://docs.docker.com/articles/using_supervisord/

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