How to install and launch PostgreSQL as part of a stand-alone Python-based application? - postgresql

Question

I have created a Python application that utilizes a PostgreSQL database and now I'd like to package it as a stand-alone application. I have worked out how to package everything as a single executable using PyInstaller however it will fail upon launch when attempting to establish a connection to the database if it doesn't exist. To address this my assumption is that I need to also include a mechanism for installing and launching a PostgreSQL database instance if it's not present.
I'm trying to provide a single installation process that creates/configures/launches the database (if not present) and installs the application's executable. I want to create installers for Linux, Windows, and MacOS.
How do I best go about this? I am hoping to find documentation for a solution to this use case -- my Google-Fu appears to be weak and/or the solution is obscure.

Answer 1

Handling external software is not the purpose of Pyinstaller. So you need to handle its dependencies by yourself. So about your question, you need to first find a portable version of PostgreSQL, then in your script, run and configure it manually. For example, there is a good portable version in here.
Just extract the contents of PGRE portable to a directory like PostgreSQL next to your python script (app.py).
Then you can use the below code to launch Database:
import subprocess
import os
import sys
PGRE_EXE = "PostgreSQL/PostgreSQLPortable.exe"
def resource_path(relative_path):
if hasattr(sys, '_MEIPASS'):
return os.path.join(sys._MEIPASS, relative_path)
return os.path.join(os.path.abspath("."), relative_path)
def start_pgre():
pgre_path = os.path.join(resource_path("."), PGRE_EXE)
print(pgre_path)
p = subprocess.Popen(
[pgre_path], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout, stderr = p.communicate()
print(stdout)
print(stderr)
if __name__ == "__main__":
start_pgre()
Then add the whole PostgreSQL as external data with --add-data:
pyinstaller -F --add-data "./PostgreSQL:PostgreSQL" app.py