[PATCH v26 00/15] Log subsystem improvements

[David Marchand]

Hello Stephen,

On Wed, Oct 16, 2024 at 10:24 PM Stephen Hemminger
<stephen at networkplumber.org> wrote:
>
> Improvements and unification of logging library.
> This version works on all platforms: Linux, Windows and FreeBSD.
>
> This is update to rework patch set. It adds several new features
> to the console log output.
>
>   * Putting a timestamp on console output which is useful for
>     analyzing performance of startup codes. Timestamp is optional
>     and must be enabled on command line.
>
>   * Displaying console output with colors.
>     It uses the standard conventions used by many other Linux commands
>     for colorized display.  The default is to enable color if the
>     console output is going to a terminal. But it can be always
>     on or disabled by command line flag. This default was chosen
>     based on what dmesg(1) command does.
>
>     Color is used by many tools (vi, iproute2, git) because it is helpful;
>     DPDK drivers and libraries print lots of not very useful messages.
>     And having error messages highlighted in bold face helps.
>     This might also get users to pay more attention to error messages.
>     Many bug reports have earlier messages that are lost because
>     there are so many info messages.
>
>   * Add support for automatic detection of systemd journal
>     protocol. If running as systemd service will get enhanced
>     logging.
>
>   * Use of syslog is optional and the meaning of the
>     --syslog flag has changed. The default is *not* to use
>     syslog if output is going to a terminal.
>
> Add myself as maintainer for log because by now have added
> more than previous authors.

Thanks for the series.

Overall, it looks good, but I am too short on time for merging in rc1
and I have some comments.
I'll consider merging it in rc2.


- The main point is the "automatic" aspect but we want to provide some
way to force where the logs end up.
With this series, the user has --syslog (whose meaning is changed) and
--log-journal options to affect where the logs go.
Can we get a single option?
Like maybe --log-destination=console|syslog|journal|auto ?

- I don't really understand why changing the --syslog is better.
We lose the ability to select the syslog facility.
Either this feature was useless, and I would rather deprecate or
remove it explicitly (and the --syslog with it).
Or we should keep it as is for compat reason.


- The color and timestamping options only affect the console output,
which is not clear with the --log-color / --log-timestamp names.
Maybe we can enhance with some other name?


- Did you test redirecting all logs to an external logging function?
I suppose it still works, but it is important not to break such feature for OVS.


-- 
David Marchand