How to run pg_cron via Dockerfile

Few months ago I wrote about how you can have cron jobs in Postgres using pg_cron. But I didn't really specify how to install pg_cron. While pg_cron is a great addition to Postgres, it's not a built-in feature.

So in this post, I'll show you how to quickly have a Postgres that has pg_cron installed. You can simply use the following Dockerfile to install pg_cron:

FROM postgres:15
RUN apt-get update && apt-get install -y curl
RUN apt-get -y install postgresql-15-cron
RUN echo "shared_preload_libraries='pg_cron'" >> /usr/share/postgresql/postgresql.conf.sample
RUN echo "cron.database_name='postgres'" >> /usr/share/postgresql/postgresql.conf.sample

Then you need to build the image first:

docker build -t postgres-with-cron .

Once the image is built, you can run it with the following command:

docker run  \
  --name postgres-cron \
  -e POSTGRES_PASSWORD=mysecretpassword \
  -p 5432:5432 \
  postgres-with-cron

One last thing to do is to run the following query in the postgres database:

CREATE EXTENSION IF NOT EXISTS pg_cron;

That's it! Now you can use pg_cron in your Postgres database.

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