[systemd-devel] python - reading the journal

Steven Hiscocks steven-systemd at hiscocks.me.uk
Mon Feb 4 14:42:02 PST 2013

On 04/02/13 18:30, Steven Hiscocks wrote:
> On 04/02/13 05:13, David Strauss wrote:
>> I second the interest in committing this to the existing Python
>> support once polished.
>> On Sun, Feb 3, 2013 at 6:07 PM, Zbigniew Jędrzejewski-Szmek
>> <zbyszek at in.waw.pl> wrote:
>>> On Sun, Feb 03, 2013 at 09:18:28PM +0000, Steven Hiscocks wrote:
>>>> Hi,
>>>> I've been developing a python module for accessing the journal,
>>>> using the journal API. (https://github.com/kwirk/pyjournalctl)
>>> Great! Have you thought about including it in the systemd repo,
>>> once interface nad implementation is stabilized?
>>>> One issue I've had is with 'sd_journal_seek_monotonic_usec'. When
>>>> called, followed by call to 'sd_journal_next', I end up at the start
>>>> of the journal.
>>>> If I set a match for "_BOOT_ID" , before (or after) the call to
>>>> 'sd_journal_seek_monotonic_usec' (with same "_BOOT_ID"), it then
>>>> behaves as I would expect and returns the closest log entry to the
>>>> monotonic time stamp.
>>>> I was wondering if this is this the intended behaviour, or is this a
>>>> bug?
>>> Looking at the docs, it seems OK. Without _BOOT_ID the behaviour
>>> is unspecified.
>>> Some comments about the API:
>>>>>> journal.add_match("PRIORITY", "5")
>>> Why not journal.add_match(PRIORITY="5") ?
>>> Likewise journal.add_matches({"PRIORITY": "5", "_PID": "1"})
>>> could be written as journal.add_matches(PRIORITY=5, _PID=1).
>>> This would mirror the journal API which is part of the python-systemd
>>> module.
>>> Note: systemd.journal already has LOG_EMERG and friends (imported
>>> from syslog), so there's no need to use plain numbers.
>>> Your object-oriented approach, python 2/3 compatiblity, GIL releasing
>>> support are great. I would definitely want to pull this into the
>>> python-systemd.
>>> Zbyszek
> Thanks both for the positive feedback.
> So if I understand correctly, a _BOOT_ID match must be in place for
> sd_journal_seek_monotonic_usec to function correctly?
> It would be great for it too be included in the systemd repo! I'll look
> at making the suggested changes. I think that using keyword arguments
> will make add_matches redundant, so I'll probably drop that and just
> have the add_match method.

I've made the suggested changes and pushed it to github. Feedback 
welcomed :)

Steven Hiscocks

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