[systemd-devel] python - reading the journal

Zbigniew Jędrzejewski-Szmek zbyszek at in.waw.pl
Mon Feb 4 18:49:34 PST 2013


On Mon, Feb 04, 2013 at 10:42:02PM +0000, Steven Hiscocks wrote:
> I've made the suggested changes and pushed it to github. Feedback
> welcomed :)

Some more thoughts on the API below. Some of those are probably
stupid, but I want to throw them out in the open, for your feedback.

SD_MESSAGE_* are string constants. Shouldn't they be int constants
like in C? The conversion both ways is pretty simple, but if the
constants were used outside of journal matches it would be nicer
to have them as ints. The downside would be that the user
would have to printf the int to use it in a match. But... see next

It would be nice to expose the rest of sd-id128 API:
sd_id128_to_string(3), sd_id128_randomize(3),
sd_id128_get_machine(3). They would probably go in a separate module
(systemd.id128), since they are useful in writing journal entries too.

>>> journal.seek_monotonic(int(monotonic.total_seconds()*1E6), bootid)
Python interfaces usually use floating point numbers to mean
seconds. A double has ~16 significant numbers, so the accuracy should
be enough, so I believe the detail that this is microseconds should
be hidden.

It would be better to replace PyRun_String with normal C methods,
but that can be done later.

sd_journal_open_directory is not wrapped, but that can be added

What about renaming Journalctl to Journal? It doesn't really control
anything :)

SD_JOURNAL_LOCAL_ONLY should probably be renamed to LOCAL_ONLY
(SD_JOURNAL_RUNTIME_ONLY, SYSTEM_ONLY likewise). Here namespaceing
will be provided by the module, so there's no need for the long name.

Second argument to .seek(), a documentation only change: it would be
nice to use io.SEEK_SET, io.SEEK_CUR, io.SEEK_END in the description.

Should .query_unique() return a set instead? This would make checking
if an field is present faster, and also underline the fact that those
are non-repeating entries.

Your module will be great for creating a test suite for journal. At the
same time it will also serve as a test suite for the module.


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