journalwatch bug: bytes-like objects

[hdak1945git]

Greetings!

I've been using journalwatch for quite a while and haven't had any issues until I recently installed mpd (Music Player Daemon).

It's quite chatty by default in Arch Linux and sometimes it outputs data that journalctl considers binary in nature; which it masks as "blob data".

However this type of log data causes journalwatch (0.2.2) to crash with a (seemingly) unhelpful stack trace.

I've created a patch that fixes the issue by emulating journalctl's behavior. Further below is more details regarding the patch and the problem at hand.

Patch: https://gist.github.com/hdak1945git/1943dcf77a5534e865fde591b9939955

---

When journalwatch (0.2.2) encounters lines marked as "binary" it throws an exception when filtering:

Traceback (most recent call last):
  File "/usr/bin/journalwatch", line 22, in <module>
    sys.exit(journalwatch.main())
  File "/usr/lib/python3.5/site-packages/journalwatch.py", line 466, in main
    run()
  File "/usr/lib/python3.5/site-packages/journalwatch.py", line 453, in run
    if not filter_message(patterns, entry):
  File "/usr/lib/python3.5/site-packages/journalwatch.py", line 310, in filter_message
    if filt.match(entry['MESSAGE']):
TypeError: cannot use a string pattern on a bytes-like object

Skimming through the system log with a plain journalctl results in various lines with text similar to [66B blob data]. Running journalctl -a shows what I'm assuming to be malformed UTF8 -- mpd was specifically complaining about ID3 tags for a few certain Japanese songs.

The patch works against these lines in journalwatch.py:

• line:282 in format_entry: words.append(entry.get('MESSAGE', 'EMPTY!'))
• line:310 in filter_messsage: if filt.match(entry['MESSAGE']):

With a function wrapping around entry.get, replacing bytes-typed data (when specified) with a formatted string similar to:

[journalwatch: {data_length}B blob data]

[The-Compiler]

Thanks! The patch looks good apart from some style issues - I'll apply it later today.

[The-Compiler]

This was a loooong "later today" - sorry for that, I somehow completely forgot about journalwatch again 😆