Restore a Postgresql database into a Docker container so when Postgres starts up the DB is in place

As Stackoverflow penaltizes answers which are too succinct I repeat what is written there:

1. Create a data only container
2. Run a temporary Postgres container to restore the backup. Attach the data only container AND the directory containing the local backup.
3. Attach to the restore container. Within the container,
4. Switch to the postgresql user
5. Create the superuser and matching password for the database to restore.
6. Exit the psql session with \q. Still within the container,
7. restore the backup on the command prompt
8. Create the final Docker Postgres container. Note to specify the correct name of the database the restore has been made into from the previous step.
9. delete the container used to restore the backup into the data only volume

The easiest would be to create an empty postgresql database on the host in separate folder, then start the PostgreSQL daemon, then import the data and then simply mount it to the container. Using the script below you can create the DB in /tmp/postgres-mem folder and then import data into it.

#!/bin/bash

export PGDIR=/tmp/postgres-mem

pg_ctl -D "$PGDIR" stop

rm -vfr "$PGDIR"

mkdir "$PGDIR"

pg_ctl init -D "$PGDIR"

pg_ctl -D "$PGDIR" start -o "-h localhost -c fsync=off -c synchronous_commit=off -c full_page_writes=off -c log_destination='stderr' -c logging_collector=on -c log_directory='pg_log' -c log_filename='postgresql-%Y-%m-%d_%H%M%S.log' -c log_statement='all' -k /tmp/postgres-mem"

sleep 3

psql -h localhost -c 'create user cooluser with superuser' template1
psql -h localhost -c 'create database "whatever"' template1

and then

psql -U cooluser whatever < your_dump_file.sql

then you copy the content of /tmp/postgres-mem into your data container

However you may want to consider this approach.