[Freeipa-devel] [PATCH 0434] log: add timestamp to filename of logs

[Jan Cholasta]

On 14.3.2016 13:56, Rob Crittenden wrote:
> Jan Cholasta wrote:
>> On 11.3.2016 15:56, Gabe Alford wrote:
>>> On Fri, Mar 11, 2016 at 7:35 AM, Petr Vobornik <pvoborni at redhat.com
>>> <mailto:pvoborni at redhat.com>> wrote:
>>>
>>>      On 03/11/2016 03:00 PM, Rob Crittenden wrote:
>>>
>>>          Martin Kosek wrote:
>>>
>>>              On 03/11/2016 09:55 AM, Jan Cholasta wrote:
>>>
>>>                  On 11.3.2016 09:33, Martin Kosek wrote:
>>>
>>>                      On 03/08/2016 07:07 PM, Martin Basti wrote:
>>>
>>>
>>>
>>>                          On 08.03.2016 16:37, Martin Basti wrote:
>>>
>>>
>>>
>>>                              On 08.03.2016 16:31, Martin Basti wrote:
>>>
>>>
>>> https://fedorahosted.org/freeipa/ticket/4501
>>>
>>>                                  Patch attached.
>>>
>>>
>>>                              Rebased patch attached.
>>>
>>>
>>>
>>>                          self-NACK
>>>
>>>                          Scripts print to CLI unformatted strings, it
>>>                          should not be so easy.
>>>                          See /var/log/ipaupgrade-{timestamp}.log for more
>>>                          information
>>>
>>>
>>>                      second-NACK. We cannot break existing log file
>>>                      paths. The paths are mentioned
>>>                      in a documentation and there may be also automation
>>>                      around that (gathering log
>>>                      files). So there should be always symlink from the
>>>                      well known location to the
>>>                      newest timestampe'd log.
>>>
>>>
>>>                  Sorry, but this is absurd. What's the point of
>>>                  maintaining backward
>>>                  compatibility with obsolete documentation? Following
>>>                  this logic, we would not
>>>                  be able to change anything ever. What we should actually
>>>                  do is update the
>>>                  documentation. Ditto for automation.
>>>
>>>
>>>              +1 for updating the automation and documentation. But some
>>>              backward
>>>              compatibility will need to be retained, at least for the
>>>              stable systems like
>>>              RHEL where *other* people may have some automation or
>>>              documentation around it,
>>>              not just us.
>>>
>>>
>>>          Or you could just also create a symlink to the old name and it
>>> will
>>>          always just work.
>>>
>>>          rob
>>>
>>>
>>>      Aren't the symlinks what Martin2 mentioned in second-NACK?
>>>
>>>      These new timestamped logs should be combined with the Gabe's
>>>      patches: #5728 (renamed to command name) and #5724 (move to
>>>      /var/log/ipa directory).
>>>
>>>      So that there will be e.g.:
>>>      /var/log/ipaserver-install.log ->
>>>      /var/log/ipa-server-install-{timestamp}.log
>>>
>>>      /var/log/ipa/ipa-server-install.log ->
>>>      /var/log/ipa-server-install-{timestamp}.log
>>>
>>>
>>> I wonder if it would be simpler/better to always write to the *.log
>>> file, and then have old logs timestamped rather than write directly to a
>>> timestamped log file?
>>> Then just symlink the original log file in /var/log/ to the new log file
>>> name/location in /var/log/ipa.
>>>
>>> For example:
>>> /var/log/ipaserver-install.log ->
>>> /var/log/ipa/ipa-server-install.log                <-- We write to this
>>> log (current)
>>>
>>> /var/log/ipa-server-install-{timestamp}.log   <-- Old log with some date
>>>
>>> /var/log/ipa-server-install-{timestamp}.log   <-- Older log with some
>>> date
>>>
>>> /var/log/ipa-server-install-{timestamp}.log   <-- Oldest log with some
>>> date
>>
>> This is way too overengineered for something that should actually be
>> really simple. I don't care if it is done this way or not, but IMHO it
>> would be a waste of time. Logs are not API and should not be treated as
>> such. If it needs to be done differently on RHEL, it should be handled
>> downstream.
>
> Sure logs are not API but they have been named the same way since
> inception (nearly 8 years now). I don't think symlinking to the old
> names is a big deal.

It kind of is, since you have to keep the symlink up to date, handle the 
case when there is a regular file in place of the symlink, and they 
won't work properly for commands which currently append to their log 
files rather than overwrite them anyway.

To do this properly, you have to add a new FileHandler with proper 
options for each old log file. IMHO there is no benefit in doing this 
upstream, but it is relatively straightforward and isolated to be done 
downstream.

-- 
Jan Cholasta