Changes to _Reader make it match closer to C API, by removing `get_next`
and `get_previous`. A `get_all` method added, which returns dictionary
of fields using C API SD_JOURNAL_FOREACH_DATA macro, which can be used
in conjunction with `next`.
_Reader `get`, `next`, `get_{realtime,monotonic,cursor}` and new
`previous` methods are made private. This is so the traversal and
getting of journal fields can be made transparent in the python
interface.
Reader now solely implements `get_next` and `get_previous`, returning a
standard dictionary (future: other mapping types?) with all standard and
special fields through the converters. This makes the output the same as
journalctl json/export format output.
Iterator methods also moved to Reader, as they do not function as intend
with changes to _Reader.
These changes also mean that more optimised journal interfaces can be
made more easily from _Reader, by avoiding getting of unrequired fields
by using the `_get` method, and avoiding field conversions.
The behaviour wrt. seconds vs. microseconds was inconsistent.
Now _Reader always uses native units (us), while Reader always
uses seconds and accepts both floats and ints. This way the
conversion is always done in the Python layer, and the lower
level API allows access to the journal API without the potentially
lossy conversion between double and uint64_t.
It's better to explictly check, instead of just documenting it.
The return value from init is changed from 1 to -1 on error.
Python seems to ignore 1 every second time. Looks like a bug
in Python, but the return value doesn't seem to be documented
anywhere, and -1 works as expected... so let's just use that.
First of all, 'try: ... except: ...' (with no exception specified) is
always a no-no, since it catches all BaseExceptions, which includes ^C
and other stuff which should almost never be caught.
Now the conversion is stricter, and only one conversion is attempted,
and only a ValueEror is caught. It seems reasonable to catch ValueErrors,
since the entries in the journal are not verified, and any erroneous
application might log a field which cannot be converted. The consumer
of events must only check if a field is an instance of bytes and can
otherwise assume that the conversion was performed correctly.
Order of arguments in Reader.__init__ has been changed to match order
in _Reader.__init__.
Conversions have been updated to work under Python 2 and 3.
It seems inevitable that we'll also grow a writing interface,
and then it'll be cumbersome to have a "Journal" for reading,
and a "Writer" for writing.
__REALTIME_TIMESTAMP and __MONOTONIC_TIMESTAMP return ints.
It doesn't make sense to convert to string, just to convert
back to a number later on.
Also try to follow systemd rules for indentation.
Supports Python versions 2.6 through 3.3 (tested on 2.7 and 3.2).
See JournalHandler docstring for usage details.
[zj: - use send() instead of using sendv() directly
- do exception handling like in the logging module
- bumped min version to python2.6, since the module
does not work with python2.5 anyway ]
