tmp-postgres

tmp-postgres provides functions creating a temporary postgres instance. By default it will create a temporary directory for the data, a random port for listening and a temporary directory for a UNIX domain socket.

Here is an example using the expection safe 'with' function:

 with $ \db -> bracket (connectPostgreSQL (toConnectionString db)) close $ \conn ->
  execute_ conn "CREATE TABLE foo (id int)"

To extend or override the defaults use withConfig (or startConfig).

tmp-postgres ultimately calls initdb, postgres and createdb. All of the command line, environment variables and configuration files that are generated by default for the respective executables can be extended or overrided.

All tmp-postgres by default is most useful for creating tests by configuring "tmp-postgres" differently it can be used for other purposes.

• By disabling initdb and createdb one could run a temporary postgres on a base backup to test a migration.
• By using the stopPostgres and withRestart functions one can test backup strategies.

The level of custom configuration is extensive but with great power comes ability to screw everything up. tmp-postgres doesn't validate any custom configuration and one can easily create a Config that would not allow postgres to start.

Installation

macOS

$ brew install postgres
$ stack install tmp-postgres

Ubuntu

Ubuntu's PostgreSQL installation does not put initdb on the PATH. We need to add it manually.

$ sudo apt-get install postgresql-VERSION
$ echo "export PATH=$PATH:/usr/lib/postgresql/VERSION/bin/" >> /home/ubuntu/.bashrc
$ stack install tmp-postgres