events: add progress bar to event expiry migration

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

authentik/events/migrations/0014_expiry.py

@@ -1,6 +1,7 @@
 # Generated by Django 3.1.7 on 2021-03-18 16:01
 
 from datetime import timedelta
+from typing import Iterable
 
 from django.apps.registry import Apps
 from django.db import migrations, models
@@ -9,11 +10,59 @@ from django.db.backends.base.schema import BaseDatabaseSchemaEditor
 import authentik.events.models
 
 
+# Taken from https://stackoverflow.com/questions/3173320/text-progress-bar-in-the-console
+def progress_bar(
+    iterable: Iterable,
+    prefix="Writing: ",
+    suffix=" finished",
+    decimals=1,
+    length=100,
+    fill="█",
+    print_end="\r",
+):
+    """
+    Call in a loop to create terminal progress bar
+    @params:
+        iteration   - Required  : current iteration (Int)
+        total       - Required  : total iterations (Int)
+        prefix      - Optional  : prefix string (Str)
+        suffix      - Optional  : suffix string (Str)
+        decimals    - Optional  : positive number of decimals in percent complete (Int)
+        length      - Optional  : character length of bar (Int)
+        fill        - Optional  : bar fill character (Str)
+        print_end   - Optional  : end character (e.g. "\r", "\r\n") (Str)
+    """
+    total = len(iterable)
+    if total < 1:
+        return
+
+    def print_progress_bar(iteration):
+        """Progress Bar Printing Function"""
+        percent = ("{0:." + str(decimals) + "f}").format(
+            100 * (iteration / float(total))
+        )
+        filledLength = int(length * iteration // total)
+        bar = fill * filledLength + "-" * (length - filledLength)
+        print(f"\r{prefix} |{bar}| {percent}% {suffix}", end=print_end)
+
+    # Initial Call
+    print_progress_bar(0)
+    # Update Progress Bar
+    for i, item in enumerate(iterable):
+        yield item
+        print_progress_bar(i + 1)
+    # Print New Line on Complete
+    print()
+
+
 def update_expires(apps: Apps, schema_editor: BaseDatabaseSchemaEditor):
     db_alias = schema_editor.connection.alias
 
+    print("\nAdding expiry to events, this might take a couple of minutes...")
+
     Event = apps.get_model("authentik_events", "event")
-    for event in Event.objects.using(db_alias).all():
+    all_events = Event.objects.using(db_alias).all()
+    for event in progress_bar(all_events):
         event.expires = event.created + timedelta(days=365)
         event.save()