Fix PluginOutputHookImplementation gets called twice #5271

[moreamazingnick]

Concatenate Output.

This might break workarounds used implemented in a PluginOutputHookImplementation but I haven't found any out in the wild.

This removes the annoying space between the first line and the other lines in the monitoring module plugin output

Alternatives :
Introduce a monitoring setting that disables this fix for a fast switch back in case this breaks something

Best Regards
Nicolas

[nilmerg]

This might break workarounds used implemented in a PluginOutputHookImplementation but I haven't found any out in the wild.

Yeah. Though, I think mentioning this in the upgrade documentation should suffice. Please adjust this as well.

[moreamazingnick]

@nilmerg do you mean I should edit this as well?
https://github.com/Icinga/icingaweb2/blob/main/CHANGELOG.md

[nilmerg]

No, the upgrade documentation. You can refer to the 2.11.x framework changes to get an idea how.

[moreamazingnick]

Something like that:

Upgrading to Icinga Web 2.12.2

Framework changes affecting third-party code

• (monitoring/ido) When rendering the Icinga check output, the output and long_output fields are now concatenated with a newline (\n) before any post-processing occurs, such as through a PluginOutputHook

[nilmerg]

Yep. But instead of (monitoring/ido), mention the absolute class path of the hook. (With code highlighting using single backticks)

[nilmerg]

LGTM!