Sept 3, 2025
Continuing from the posts of the last two days, I want to describe how I control the Pharo server process on my Linux machine. Most Linux versions use a framework called systemd (see also systemd's Wikipedia entry) to setup, manage and control so called daemons or server processes. We want to integrate with systemd to be a nice Linux server citizen. This will help sysadmins recognize us as a something they understand.
You need two things:
Here is the contents of zinc-http-server-nxt.service, our service specification:
[Unit]
Description=Zinc HTTP Components Server NXT
After=network.target
[Service]
Type=forking
User=stfx
WorkingDirectory=/home/stfx/pharo13
ExecStart=/home/stfx/pharo13/pharo-ctl.sh run-zn start zinc
ExecStop=/home/stfx/pharo13/pharo-ctl.sh run-zn stop zinc
PIDFile=/home/stfx/pharo13/run-zn.pid
Restart=always
[Install]
WantedBy=default.target
Although there exist many features and options, the basic idea should be clear.
We refer to a working directory where a script called pharo-ctl.sh lives
that can start and stop our Pharo server, leaving a PID file behind when started
(a file containing the OS's process identifier of Pharo).
The pharo-ctl.sh script is a variant of
pharo-ctl.sh
in my (old) pharo-server-tools project.
Invoked without arguments, the script explains how to use it:
$ ./pharo-ctl.sh
Executing ./pharo-ctl.sh
Working directory /home/stfx/pharo13
Usage: ./pharo-ctl.sh <script> <command> <image>
manage a Pharo server
Naming
script is used as unique identifier
script.st must exist and is the Pharo startup script
script.pid will be used to hold the process id
image.image is the Pharo image that will be started
Commands:
start start the server in background
stop stop the server
restart restart the server
run run the server in foreground
pid print the process id
The script being the one I showed yesterday, the image the one we build with our packages.
In practice, you use a tool called systemctl to manage your service, once installed.
Here is the output from the status subcommand:
$ sudo systemctl status zinc-http-server-nxt
● zinc-http-server-nxt.service - Zinc HTTP Components Server NXT
Loaded: loaded (/etc/systemd/system/zinc-http-server-nxt.service; enabled; preset: enabled)
Active: active (running) since Tue 2025-09-02 15:42:04 CEST; 24h ago
Process: 820303 ExecStart=/home/stfx/pharo13/pharo-ctl.sh run-zn start zinc (code=exited, status=0/SUCCESS)
Main PID: 820306 (pharo)
Tasks: 2 (limit: 1078)
Memory: 87.6M (peak: 104.0M)
CPU: 8min 49.796s
CGroup: /system.slice/zinc-http-server-nxt.service
└─820306 /home/stfx/pharo13/pharo-vm/lib/pharo --headless /home/stfx/pharo13/zinc.image /home/stfx/pharo13/run-zn.>
Sep 02 15:42:04 audio359 systemd[1]: Starting zinc-http-server-nxt.service - Zinc HTTP Components Server NXT...
Sep 02 15:42:04 audio359 pharo-ctl.sh[820303]: Executing /home/stfx/pharo13/pharo-ctl.sh run-zn start zinc
Sep 02 15:42:04 audio359 pharo-ctl.sh[820303]: Working directory /home/stfx/pharo13
Sep 02 15:42:04 audio359 pharo-ctl.sh[820303]: Starting run-zn in background
Sep 02 15:42:04 audio359 pharo-ctl.sh[820303]: /home/stfx/pharo13/pharo-vm/pharo --headless /home/stfx/pharo13/zinc.image /home>
Sep 02 15:42:04 audio359 systemd[1]: Started zinc-http-server-nxt.service - Zinc HTTP Components Server NXT.
The top section details the current state, while the bottom section shows the tail of the log output.
Systemd will make sure our service is started automatically when the system boots, and keeps running, restarting it when needed.
Note that this is a generic solution for any Pharo Smalltalk server/service process, it just happens to be running a Zinc HTTP Components's server demo, but it could really be anything at all.