This changes greatly improves the speed of `beet export` and `beet info`
when the `--include-keys` option is used. It also removes the globbing
feature of `--include-keys` that was added in #1295. (See #3762 for
discussion).
Listing all fields for an item requires querying the database to find
any flex attributes. This is slow when done for every item being
exported. We already have a way for the user to specify a fixed set
of keys, but we previously queried everything and filtered it afterwards.
The new approach is more efficient.
Code that iterates through all fields now have to handle invalid field
names. The export and info plugins output invalid fields as None.
Timings before:
> /usr/bin/time beet export -i title,path,artist -l Bob Dylan
13.26user 20.22system 0:34.01elapsed 98%CPU (0avgtext+0avgdata 52544maxresident)k
> /usr/bin/time beet export -l Bob Dylan
12.93user 20.15system 0:33.58elapsed 98%CPU (0avgtext+0avgdata 53632maxresident)k
Timings after:
> /usr/bin/time beet export -l Bob Dylan
13.33user 20.17system 0:34.02elapsed 98%CPU (0avgtext+0avgdata 53500maxresident)k
> /usr/bin/time beet export -i title,path,artist -l Bob Dylan
0.49user 0.07system 0:00.56elapsed 98%CPU (0avgtext+0avgdata 50496maxresident)k
Notice the dramatic speedup in the last example!
Squashed from the PR, relevant commit messages follow below:
Added file size option to artresizer
- In line with comments on PR, adjusted the ArtResizer API to add
functionality to "resize to X bytes" through `max_filesize` arg
- Adjustment to changelog.rst to include max_filesize change to ArtResizer
and addition of new plugin.
Added explicit tests for PIL & Imagemagick Methods
- Checks new resizing functions do reduce the filesize of images
Expose max_filesize logic to fetchart plugin
- Add syspath escaping for OS cross compatibility
- Return smaller PIL image even if max filesize not reached.
- Test resize logic against known smaller filesize (//2)
- Pass integer (not float) quality argument to PIL
- Remove Pillow from dependencies
- Implement "max_filesize" fetchart option, including
logic to resize and rescale if maxwidth is also set.
Added tests & documentation for fetchart additions.
Tests now check that a target filesize is reached with a
higher initial quality (a difficult check to pass).
With a starting quality of 95% PIL takes 4 iterations to succeed
in lowering the example cover image to 90% its original size.
To cover all bases, the PIL loop has been changed to 5 iterations
in the worst case, and the documentation altered to reflect the
50% loss in quality this implies. This seems reasonable as users
concerned about performance would most likely be persuaded to
install ImageMagick, or remove the maximum filesize constraint.
The previous 30% figure was arbitrary.
