XML filter or prune filter more suited for this log file? Or simply grok it?

[Callahan]

This is the output I get from querying a Sonos speaker using a Python script that I've got outputting to a file. I have 2 questions. Firstly, my aim is to extract only a small segment of info from this text file. Specifically, I want to only extract the following :
dc:titleFinally Moving</dc:title>
dc:creatorPretty Lights</dc:creator>
upnp:albumPrime Chill</upnp:album>

Prune seems to be more suited to this as there is so little I actually want from this file.

My second question is, I plan to run this script every 5 mins and output the log file overwriting the existing output file. Can anyone confirm my beleif that when Logstash sees a new file, it will ingest it and throw the results to Elasticsearch even if the output file has the same name?

The content I want to filter:

e[37mResponse:
e[36m{u'AbsTime': u'NOT_IMPLEMENTED', u'@xmlns:u': u'urn:schemas-upnp-org:service:AVTransport:1', u'Track': u'30', u'TrackDuration': u'0:04:38', u'TrackURI': u'x-sonosapi-hls-static:catalog%2ftracks%2fB0037858OA%2f%3fplaylistAsin%3dB07J1GFY3G%26playlistType%3dprimePlaylist?sid=201&flags=0&sn=1', u'RelTime': u'0:00:21', u'TrackMetaData': u'<DIDL-Lite xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:upnp="urn:schemas-upnp-org:metadata-1-0/upnp/" xmlns:r="urn:schemas-rinconnetworks-com:metadata-1-0/" xmlns="urn:schemas-upnp-org:metadata-1-0/DIDL-Lite/"><item id="-1" parentID="-1" restricted="true"><res protocolInfo="sonos.com-http:*:application/x-mpegURL:*" duration="0:04:38">x-sonosapi-hls-static:catalog%2ftracks%2fB0037858OA%2f%3fplaylistAsin%3dB07J1GFY3G%26playlistType%3dprimePlaylist?sid=201&amp;flags=0&amp;sn=1</res><r:streamContent></r:streamContent><upnp:albumArtURI>/getaa?s=1&amp;u=x-sonosapi-hls-static%3acatalog%252ftracks%252fB0037858OA%252f%253fplaylistAsin%253dB07J1GFY3G%2526playlistType%253dprimePlaylist%3fsid%3d201%26flags%3d0%26sn%3d1</upnp:albumArtURI><dc:title>Finally Moving</dc:title><upnp:class>object.item.audioItem.musicTrack</upnp:class><dc:creator>Pretty Lights</dc:creator><upnp:album>Prime Chill</upnp:album></item></DIDL-Lite>', u'RelCount': u'2147483647', u'AbsCount': u'2147483647'}

Thanks for any advice you have.