Problem with a Golang webapp and system service

I am trying to create a Golang server using the gin framework on ubuntu. It works fine when it is executed in the terminal after building it with go build and equally works well locally.

Systemd

Description=goapp

[Service]
Type=simple
Restart=always
RestartSec=5s
ExecStart=/home/.../goapp/main


[Install]
WantedBy=multi-user.target

I got this error

goapp.service - rediate
Loaded: loaded (/lib/systemd/system/goapp.service; disabled; vendor preset: enabled)
Active: activating (auto-restart) (Result: exit-code) since Thu 2022-09-29 08:14:10 UTC; 66ms ago
Process: 21628 
ExecStart=/home/.../go/goapp/main (code=exited, status=2)
Main PID: 21628 (code=exited, status=2)
CPU: 9ms

Go is compiled language. You need to build your code into an executable binary file using go build command and then give path to binary file to systemd via ExecStart property in unit file.

See Go Documentation and specifically Compile and install the application section to find out more about how to compile your application.

In your example you have ExecStart=/home/.../goapp/main.go which is telling systemd to run source code file. That file is not executable and understood by operating system so it fails to execute and systemd unit fails because of that.

Adding a working directory to the systemd fix this error.

Description=goapp

[Service]
Type=simple
Restart=always
RestartSec=
WorkingDirectory=/home/.../goapp
ExecStart=/home/.../goapp/main


[Install]
WantedBy=multi-user.target