Pull request 2237: 7053 journald Log

Updates #7053.

Squashed commit of the following:

commit f763a229660c00013fbd51cf7a3deabf00a01787
Merge: 06fc83d08 8432593be
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Jun 17 17:52:11 2024 +0300

    Merge branch 'master' into 7053-journald-log

commit 06fc83d08e
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Thu Jun 13 15:59:35 2024 +0300

    all: imp chlog

commit 1f57a7e84a
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Jun 11 20:36:55 2024 +0300

    all: imp chlog

commit 7c9a2547a8
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Jun 11 18:33:26 2024 +0300

    home: imp doc

commit 63731e7ba5
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Jun 11 18:27:31 2024 +0300

    home: imp systemd script

CHANGELOG.md

@@ -30,11 +30,29 @@ NOTE: Add new changes BELOW THIS COMMENT.
 ### Changed
 
 - Frontend rewritten in TypeScript.
+- The `systemd`-based service now uses `journal` for logging by default.  It
+  also doesn't create the `/var/log/` directory anymore ([#7053]).
+
+  **NOTE:** With an installed service for changes to take effect, you need to
+  reinstall the service using `-r` flag of the [install script][install-script]
+  or via the CLI (with root privileges):
+
+  ```sh
+  ./AdGuardHome -s uninstall
+  ./AdGuardHome -s install
+  ```
+
+  Don't forget to backup your configuration file and other important data before
+  reinstalling the service.
 
 ### Deprecated
 
 - Node 18 support, Node 20 will be required in future releases.
 
+[#7053]: https://github.com/AdguardTeam/AdGuardHome/issues/7053
+
+[install-script]: https://github.com/AdguardTeam/AdGuardHome/?tab=readme-ov-file#automated-install-linux-and-mac
+
 <!--
 NOTE: Add new changes ABOVE THIS COMMENT.
 -->

internal/home/service.go

@@ -460,8 +460,9 @@ var launchdConfig = `<?xml version='1.0' encoding='UTF-8'?>
 //  1. The RestartSec setting is set to a lower value of 10 to make sure we
 //     always restart quickly.
 //
-//  2. The ExecStartPre setting is added to make sure that the log directory is
-//     always created to prevent the 209/STDOUT errors.
+//  2. The StandardOutput and StandardError settings are set to redirect the
+//     output to the systemd journal, see
+//     https://man7.org/linux/man-pages/man5/systemd.exec.5.html#LOGGING_AND_STANDARD_INPUT/OUTPUT.
 const systemdScript = `[Unit]
 Description={{.Description}}
 ConditionFileIsExecutable={{.Path|cmdEscape}}
@@ -471,7 +472,6 @@ ConditionFileIsExecutable={{.Path|cmdEscape}}
 [Service]
 StartLimitInterval=5
 StartLimitBurst=10
-ExecStartPre=/bin/mkdir -p /var/log/
 ExecStart={{.Path|cmdEscape}}{{range .Arguments}} {{.|cmd}}{{end}}
 {{if .ChRoot}}RootDirectory={{.ChRoot|cmd}}{{end}}
 {{if .WorkingDirectory}}WorkingDirectory={{.WorkingDirectory|cmdEscape}}{{end}}
@@ -479,8 +479,8 @@ ExecStart={{.Path|cmdEscape}}{{range .Arguments}} {{.|cmd}}{{end}}
 {{if .ReloadSignal}}ExecReload=/bin/kill -{{.ReloadSignal}} "$MAINPID"{{end}}
 {{if .PIDFile}}PIDFile={{.PIDFile|cmd}}{{end}}
 {{if and .LogOutput .HasOutputFileSupport -}}
-StandardOutput=file:/var/log/{{.Name}}.out
-StandardError=file:/var/log/{{.Name}}.err
+StandardOutput=journal
+StandardError=journal
 {{- end}}
 {{if gt .LimitNOFILE -1 }}LimitNOFILE={{.LimitNOFILE}}{{end}}
 {{if .Restart}}Restart={{.Restart}}{{end}}