Why doesn't my application behave the same when it's launched by systemd.service as when it's launched manually?

Question

I've got a dotnet API running on my raspberry, when I lauch the executable manually, it listens on http://<raspberry_ip>:<custom-port> as configured on my appsettings.json but when I use it as a service on my raspberry boot, it lauches on http://localhost:5000.

I know something must be missing in my /lib/systemd/system/<app>.service but I failed to see what.

My service configuration :

[Unit]
Description=Lauches API on boot
After=multi-user.target

[Service]
ExecStart=/home/<user>/Dev/<app_executable>
User=<user>

[Install]
WantedBy=multi-user.target

It seems quite strange, is this because of the moment the service lauches (too soon?) or am I missing something else in my configuration ?

Thanks a lot.

Ps: I also tried to change ExecStart and provide my dotnet path like so : ExecStart = /<dotnet_path> /<app_path>.dll but it didn't work either.

Answer 1

You need to set the WorkingDirectory parameter.

According to the docs:

WorkingDirectory=
Takes a directory path relative to the service's root directory specified by RootDirectory=, or the special value "~". Sets the working directory for executed processes. If set to "~", the home directory of the user specified in User= is used. If not set, defaults to the root directory when systemd is running as a system instance and the respective user's home directory if run as user. If the setting is prefixed with the "-" character, a missing working directory is not considered fatal. If RootDirectory=/RootImage= is not set, then WorkingDirectory= is relative to the root of the system running the service manager. Note that setting this parameter might result in additional dependencies to be added to the unit (see above).