Chore: Cleanup command arguments and standardize process count handling (#4541)

Cleans up some command help text and adds more control over process count for command with a Pool

src/documents/management/commands/document_thumbnails.py

@@ -6,6 +6,8 @@ import tqdm
 from django import db
 from django.core.management.base import BaseCommand
 
+from documents.management.commands.mixins import MultiProcessMixin
+from documents.management.commands.mixins import ProgressBarMixin
 from documents.models import Document
 from documents.parsers import get_parser_class_for_mime_type
 
@@ -32,13 +34,8 @@ def _process_document(doc_id):
         parser.cleanup()
 
 
-class Command(BaseCommand):
-    help = """
-        This will regenerate the thumbnails for all documents.
-    """.replace(
-        "    ",
-        "",
-    )
+class Command(MultiProcessMixin, ProgressBarMixin, BaseCommand):
+    help = "This will regenerate the thumbnails for all documents."
 
     def add_arguments(self, parser):
         parser.add_argument(
@@ -47,19 +44,20 @@ class Command(BaseCommand):
             default=None,
             type=int,
             required=False,
-            help="Specify the ID of a document, and this command will only "
-            "run on this specific document.",
-        )
-        parser.add_argument(
-            "--no-progress-bar",
-            default=False,
-            action="store_true",
-            help="If set, the progress bar will not be shown",
+            help=(
+                "Specify the ID of a document, and this command will only "
+                "run on this specific document."
+            ),
         )
+        self.add_argument_progress_bar_mixin(parser)
+        self.add_argument_processes_mixin(parser)
 
     def handle(self, *args, **options):
         logging.getLogger().handlers[0].level = logging.ERROR
 
+        self.handle_processes_mixin(**options)
+        self.handle_progress_bar_mixin(**options)
+
         if options["document"]:
             documents = Document.objects.filter(pk=options["document"])
         else:
@@ -72,11 +70,15 @@ class Command(BaseCommand):
         # with postgres.
         db.connections.close_all()
 
-        with multiprocessing.Pool() as pool:
-            list(
-                tqdm.tqdm(
-                    pool.imap_unordered(_process_document, ids),
-                    total=len(ids),
-                    disable=options["no_progress_bar"],
-                ),
-            )
+        if self.process_count == 1:
+            for doc_id in ids:
+                _process_document(doc_id)
+        else:  # pragma: no cover
+            with multiprocessing.Pool(processes=self.process_count) as pool:
+                list(
+                    tqdm.tqdm(
+                        pool.imap_unordered(_process_document, ids),
+                        total=len(ids),
+                        disable=self.no_progress_bar,
+                    ),
+                )