pgAdmin 4 on Gentoo

Since Gentoo Linux removed pgAdmin 4, you have to install it on your own. Based on the official howto for installing pgAdmin 4 as a Python package, this shows how to

place logfiles and the user database in your home directory
update pgAdmin 4
start pgAdmin 4 from your desktop environment
handle updates of Python.

Install pgAdmin 4

We will install pgAdmin 4 to ~/bin/pgadmin4 in your home directory, and will place its logfile as well as the user database in ~/.pgadmin.

$ python3 -m venv ~/bin/pgadmin4
$ . ~/bin/pgadmin4/bin/activate
$ pip install pgadmin4
$ cat >>~/bin/pgadmin4/lib/python3.9/site-packages/pgadmin4/config_local.py <<EOF
import os.path

DATA_DIR = os.path.realpath(os.path.expanduser('~/.pgadmin/'))
LOG_FILE = os.path.join(DATA_DIR, 'pgadmin4.log')
SQLITE_PATH = os.path.join(DATA_DIR, 'pgadmin4.db')
SESSION_DB_PATH = os.path.join(DATA_DIR, 'sessions')
STORAGE_DIR = os.path.join(DATA_DIR, 'storage')
AZURE_CREDENTIAL_CACHE_DIR = os.path.join(DATA_DIR, 'azurecredentialcache')
EOF

If you want to change the default port 5050 on which pgAdmin listens, add this to config_local.py:

DEFAULT_SERVER_PORT = 5051

Optionally, if you want to access pgAdmin from other hosts than your local desktop, add this:

DEFAULT_SERVER = "0.0.0.0"
# or bind it to a specific interface:
# DEFAULT_SERVER = "192.168.23.42"

In this case, you might want to limit access to certain hosts or networks:

ALLOWED_HOSTS = ("127.0.0.1", "192.168.23.0/24",)

Now start pgAdmin and create the admin user:

$ pgadmin4
NOTE: Configuring authentication for SERVER mode.

Enter the email address and password to use for the initial pgAdmin user account:

Email address: Enter your email address
Password: Enter some password
Retype password: Retype the same password
Starting pgAdmin 4. Please navigate to http://127.0.0.1:5050 in your browser.
...

Now point your web browser to the shown address, and log in with the admin credentials created right before.

Update pgAdmin 4

$ . ~/bin/pgadmin4/bin/activate
$ pip install -U pgadmin4

Start pgAdmin 4

Either create a shell script:

#!/bin/sh

. ~/bin/pgadmin4/bin/activate

echo "*** Press CTRL+C to stop pgAdmin 4 ***"
pgadmin4 | while read LINE; do
  echo "$LINE"
  url="${LINE##*navigate to }"
  url="${url%% in your browser.}"
  addrport="${url##http}"
  if [ "$addrport" != "$url" ]; then
    firefox "$url"
  fi
done

Or create an entry in your start menu, e.g. if you use Xfce:

xfce4-terminal -T pgAdmin4 -I /home/yourusername/bin/pgadmin4/lib/python3.9/site-packages/pgadmin4/pgadmin/static/favicon.ico -x bash --rcfile ~/bin/pgadmin4/bin/activate -i -c 'echo "*** Press CTRL+C to stop pgAdmin 4 ***"; pgadmin4 | while read LINE; do echo "$LINE"; url="${LINE##*navigate to }"; url="${url%% in your browser.}"; addrport="${url##http}"; if [ "$addrport" != "$url" ]; then firefox "$url"; fi; done'

Update of Python

If you have updated Python to a new version, pathes inside the venv directory (~/bin/pgadmin4) will no longer be valid. I have successfully handled updates of Python, e.g. from 3.9 to 3.10, by simply reinstalling pgAdmin4:

$ mv -iv ~/bin/pgadmin4 ~/bin/pgadmin4.old
$ python3 -m venv ~/bin/pgadmin4
$ . ~/bin/pgadmin4/bin/activate
$ pip install pgadmin4
$ cp -aiv ~/bin/pgadmin4.old/lib/python3.9/site-packages/pgadmin4/config_local.py ~/bin/pgadmin4/lib/python3.10/site-packages/pgadmin4/config_local.py

This only works if you have not placed any crucial data inside the venv directory, i.e. set DATA_DIR to a directory outside the venv, as shown by this howto.
If pgAdmin starts ok, you can remove the old venv directory:

$ rm -r ~/bin/pgadmin4.old