Remove duplicate leading slash on $SYSCONFDIR

[Elwell]

There's quite a bit of history on this edit - it's been added and removed several times over the years. Current CMake policy (CMP0192) says it's an absolute rather than relative path.

Closes #6619

---

Testing
Before we can approve your change; please submit the following in a comment:

• [N/A] Example configuration file for the change
• [N/A] Debug log output from testing the change
• [N/A] Attached Valgrind output that shows no leaks or memory corruption was found

This is a packaging change for the generation of a systemd unit file and does not alter any internals of fluent-bit.

Typical configuration on a fresh install of 4.2.2 looks like this before the change:

[root@poddy ~]# rpm -ql fluent-bit | grep serv
/usr/lib/systemd/system/fluent-bit.service
[root@poddy ~]# grep ExecStart /usr/lib/systemd/system/fluent-bit.service
ExecStart=/opt/fluent-bit/bin/fluent-bit -c //etc/fluent-bit/fluent-bit.conf
[root@poddy ~]#

Documentation

• Documentation required for this feature

Backporting

• Backport to latest stable release.

---

Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

Summary by CodeRabbit

Release Notes

• Chores
  • Updated service configuration path format to a relative-style layout, improving startup and configuration loading.
  • No changes to environment file handling or restart behavior; runtime behavior remains unchanged.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

📝 Walkthrough

Walkthrough

Removed a leading slash before the CMAKE_INSTALL_SYSCONFDIR variable in the ExecStart line of the systemd unit template to avoid producing a double slash in the configuration file path.

Changes

Cohort / File(s)	Summary
Systemd service template init/systemd.in	Removed the leading / before @CMAKE_INSTALL_SYSCONFDIR@ in the ExecStart command so the -c option no longer yields //... when expanded.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Suggested reviewers

• edsiper

Poem

A rabbit hopped in, with whiskers bright,
Found a slash that doubled in sight,
Nibbled one off, neat and spry,
Now the config path runs tidy and shy 🐇

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: removing a duplicate leading slash in the systemd unit file path configuration.
Linked Issues check	✅ Passed	The PR directly addresses issue #6619 by fixing the double slash in ExecStart path (//etc to /etc) as required.
Out of Scope Changes check	✅ Passed	The change is narrowly scoped to init/systemd.in only, directly fixing the reported double-slash issue without unrelated modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

init/systemd.in (1)

11-11: Fix correctly addresses the double-slash issue.

Removing the leading slash before @CMAKE_INSTALL_SYSCONFDIR@ properly resolves the //etc/... path problem when CMAKE_INSTALL_SYSCONFDIR is set to an absolute path.

However, consider using @CMAKE_INSTALL_FULL_SYSCONFDIR@ instead to match the pattern used for the binary path (@CMAKE_INSTALL_FULL_BINDIR@). The FULL variants are guaranteed to be absolute paths. Without it, the behavior of CMAKE_INSTALL_SYSCONFDIR depends on the CMake policy CMP0192 and the CMAKE_INSTALL_PREFIX setting—it will only be absolute when CMP0192 is NEW and CMAKE_INSTALL_PREFIX is a special prefix like / or /usr. Using CMAKE_INSTALL_FULL_SYSCONFDIR would ensure consistent behavior across all build configurations.

📜 Review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 5bb2b6c and 7c317b1.

📒 Files selected for processing (1)

• init/systemd.in

[Elwell]

The coderabbitai suggestion of switching @CMAKE_INSTALL_SYSCONFDIR@ to @CMAKE_INSTALL_FULL_SYSCONFDIR@ sounds like it would be the ideal fix to ensure that there's always a fully qualified path for the config file. The potential issue is that the binary packaging presently uses /opt/fluent-bit/ as the destinaton, and /opt is apparently handled as a special case and uses /etc/opt/ for sysconfig as per FHS.
I suspect this would therefore need testing by people with access to the build farm to ensure it didn't break all the variants.