chroma: fingerprint command's write from config

This turns on metadata-writing based on the import.write config option, so
those with this option turned off will be spared any surprises. (Affects #217
and #143.)

beetsplug/chroma.py

@@ -159,11 +159,13 @@ class AcoustidPlugin(plugins.BeetsPlugin):
         submit_cmd.func = submit_cmd_func
 
         fingerprint_cmd = ui.Subcommand('fingerprint',
-            help='fingerprints files with no fingerprint stored')
+            help='generate fingerprints for items without them')
         def fingerprint_cmd_func(lib, opts, args):
             for item in lib.items(ui.decargs(args)):
-                fingerprint_item(item, lib=lib, write=True)
+                fingerprint_item(item, lib=lib,
+                                 write=config['import']['write'].get(bool))
         fingerprint_cmd.func = fingerprint_cmd_func
+
         return [submit_cmd, fingerprint_cmd]
 
 
@@ -235,23 +237,27 @@ def submit_items(userkey, items, chunksize=64):
 
 
 def fingerprint_item(item, lib=None, write=False):
-    """Fingerprints files that don't already have prints stored
+    """Get the fingerprint for an Item. If the item already has a
+    fingerprint, it is not regenerated. If fingerprint generation fails,
+    return None. If `lib` is provided, then new fingerprints are saved
+    to the database. If `write` is set, then the new fingerprints are
+    also written to files' metadata.
     """
     # Get a fingerprint and length for this track.
     if not item.length:
         log.info(u'{0}: no duration available'.format(
             util.displayable_path(item.path)
         ))
-        return
     elif item.acoustid_fingerprint:
-        if not write:
+        if write:
+            log.info(u'{0}: fingerprint exists, skipping'.format(
+                    util.displayable_path(item.path)
+            ))
+        else:
             log.info(u'{0}: using existing fingerprint'.format(
                 util.displayable_path(item.path)
             ))
             return item.acoustid_fingerprint
-        log.info(u'{0}: skipping. fingerprint exists'.format(
-                util.displayable_path(item.path)
-        ))
     else:
         log.info(u'{0}: fingerprinting'.format(
             util.displayable_path(item.path)
@@ -259,16 +265,15 @@ def fingerprint_item(item, lib=None, write=False):
         try:
             _, fp = acoustid.fingerprint_file(item.path)
             item.acoustid_fingerprint = fp
-            if write and lib is not None:
+            if write:
                 log.info(u'{0}: writing fingerprint'.format(
                     util.displayable_path(item.path)
                 ))
                 item.write()
+            if lib:
                 lib.store(item)
             return item.acoustid_fingerprint
         except acoustid.FingerprintGenerationError as exc:
             log.info(
                 'fingerprint generation failed: {0}'.format(exc)
             )
-    return
-

docs/plugins/chroma.rst

@@ -78,9 +78,11 @@ editing your :doc:`configuration file </reference/config>`. Put ``chroma`` on
 your ``plugins:`` line. With that, beets will use fingerprinting the next time
 you run ``beet import``.
 
-You can also use ``beet fingerprint`` to fingerprint the tracks already imported
-without fingerprints. (You can provide a query to fingerprint a subset of your
-library).
+You can also use the ``beet fingerprint`` command to generate fingerprints for
+items already in your library. (Provide a query to fingerprint a subset of your
+library.) The generated fingerprints will be stored in the library database.
+If you have the ``import.write`` config option enabled, they will also be
+written to files' metadata.
 
 .. _submitfp: