task management and task runtime flow

app/common/errors.py

@@ -0,0 +1,6 @@
+class NoMediaException(Exception):
+    '''
+        Raised when a source returns no media to be indexed. Could be an invalid
+        playlist name or similar, or the upstream source returned an error.
+    '''
+    pass

app/common/static/styles/_colours.scss

@@ -2,9 +2,9 @@ $colour-white: #ffffff;
 $colour-black: #000000;
 $colour-near-black: #011627;
 $colour-near-white: #fdfffc;
-$colour-light-blue: #2e8ac4;
+$colour-light-blue: #1e5c83;
 $colour-red: #e71d36;
-$colour-orange: #ef9912;
+$colour-orange: #ff9c00;
 
 $background-colour: $colour-near-white;
 $text-colour: $colour-near-black;
@@ -37,7 +37,7 @@ $form-help-text-colour: $colour-light-blue;
 $form-delete-button-background-colour: $colour-red;
 
 $collection-no-items-text-colour: $colour-near-black;
-$collection-text-colour: $colour-near-black;
+$collection-text-colour: $colour-light-blue;
 $collection-background-hover-colour: $colour-orange;
 $collection-text-hover-colour: $colour-near-white;
 
@@ -52,6 +52,9 @@ $box-error-text-colour: $colour-near-white;
 $infobox-background-colour: $colour-near-black;
 $infobox-text-colour: $colour-near-white;
 
+$errorbox-background-colour: $colour-red;
+$errorbox-text-colour: $colour-near-white;
+
 $pagination-background-colour: $colour-near-white;
 $pagination-text-colour: $colour-near-black;
 $pagination-border-colour: $colour-light-blue;
@@ -61,3 +64,5 @@ $pagination-border-hover-colour: $colour-light-blue;
 $pagination-current-background-colour: $colour-orange;
 $pagination-current-text-colour: $colour-near-white;
 $pagination-current-border-colour: $colour-orange;
+
+$error-text-colour: $colour-red;

app/common/static/styles/_template.scss

@@ -75,6 +75,12 @@ main {
         font-size: 2rem;
     }
 
+    h2 {
+        margin: 0;
+        padding: 2rem 0 0.5rem 0;
+        font-size: 1.5rem;
+    }
+
     .btn {
         width: 100%;
         background-color: $main-button-background-colour;
@@ -90,6 +96,7 @@ main {
     .collection {
         margin: 0.5rem 0 0 0 !important;
         .collection-item {
+            transition: initial !important;
             display: block;
         }
         a.collection-item {
@@ -167,6 +174,15 @@ main {
         color: $infobox-text-colour;
     }
 
+    .errorbox {
+        background-color: $errorbox-background-colour;
+        color: $errorbox-text-colour;
+    }
+
+    .error-text {
+        color: $error-text-colour !important;
+    }
+
 }
 
 footer {

app/common/templates/base.html

@@ -31,7 +31,7 @@
           <li><a href="{% url 'sync:dashboard' %}"><i class="fas fa-fw fa-th-large"></i><span class="hide-on-med-and-down"> Dashboard</span></a></li>
           <li><a href="{% url 'sync:sources' %}"><i class="fas fa-fw fa-play"></i><span class="hide-on-med-and-down"> Sources</span></a></li>
           <li><a href="{% url 'sync:media' %}"><i class="fas fa-fw fa-film"></i><span class="hide-on-med-and-down"> Media</span></a></li>
-          <li><a href="{% url 'sync:tasks' %}"><i class="fas fa-fw fa-clock"></i><span class="hide-on-med-and-down"> Tasks</span></a></li>
+          <li><a href="{% url 'sync:tasks' %}"><i class="far fa-fw fa-clock"></i><span class="hide-on-med-and-down"> Tasks</span></a></li>
         </ul>
       </div>
     </nav>

app/common/templates/errorbox.html

@@ -0,0 +1,11 @@
+{% if message %}
+<div class="row">
+  <div class="col s12">
+    <div class="card errorbox">
+      <div class="card-content">
+        <i class="fas fa-exclamation-triangle"></i> {{ message|safe }}
+      </div>
+    </div>
+  </div>
+</div>
+{% endif %}

app/sync/admin.py

@@ -6,7 +6,7 @@ from .models import Source, Media
 class SourceAdmin(admin.ModelAdmin):
 
     ordering = ('-created',)
-    list_display = ('name',)
+    list_display = ('name', 'get_source_type_display', 'last_crawl', 'has_failed')
     readonly_fields = ('uuid', 'created')
     search_fields = ('uuid', 'key', 'name')
 

app/sync/migrations/0014_source_has_errors.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.1.4 on 2020-12-07 07:31
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sync', '0013_auto_20201207_0439'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='source',
+            name='has_errors',
+            field=models.BooleanField(default=False, help_text='Source has errors', verbose_name='has errors'),
+        ),
+    ]

app/sync/migrations/0015_auto_20201207_0744.py

@@ -0,0 +1,22 @@
+# Generated by Django 3.1.4 on 2020-12-07 07:44
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sync', '0014_source_has_errors'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='source',
+            name='has_errors',
+        ),
+        migrations.AddField(
+            model_name='source',
+            name='has_failed',
+            field=models.BooleanField(default=False, help_text='Source has failed to index media', verbose_name='has failed'),
+        ),
+    ]

app/sync/models.py

@@ -221,6 +221,11 @@ class Source(models.Model):
         default=FALLBACK_NEXT_HD,
         help_text=_('What do do when media in your source resolution and codecs is not available')
     )
+    has_failed = models.BooleanField(
+        _('has failed'),
+        default=False,
+        help_text=_('Source has failed to index media')
+    )
 
     def __str__(self):
         return self.name
@@ -307,6 +312,8 @@ class Source(models.Model):
         # Account for nested playlists, such as a channel of playlists of playlists
         def _recurse_playlists(playlist):
             videos = []
+            if not playlist:
+                return videos
             entries = playlist.get('entries', [])
             for entry in entries:
                 if not entry:

app/sync/signals.py

@@ -1,47 +1,98 @@
 from django.conf import settings
-from django.db.models.signals import post_save, pre_delete, post_delete
+from django.db.models.signals import pre_save, post_save, pre_delete, post_delete
 from django.dispatch import receiver
-
+from django.utils.translation import gettext_lazy as _
+from background_task.signals import task_failed
+from background_task.models import Task
+from common.logger import log
 from .models import Source, Media
-from .tasks import delete_index_source_task, index_source_task, download_media_thumbnail
+from .tasks import (delete_index_source_task, index_source_task,
+                    download_media_thumbnail, map_task_to_instance)
 from .utils import delete_file
 
 
+@receiver(pre_save, sender=Source)
+def source_pre_save(sender, instance, **kwargs):
+    # Triggered before a source is saved, if the schedule has been updated recreate
+    # its indexing task
+    try:
+        existing_source = Source.objects.get(pk=instance.pk)
+    except Source.DoesNotExist:
+        # Probably not possible?
+        return
+    if existing_source.index_schedule != instance.index_schedule:
+        # Indexing schedule has changed, recreate the indexing task
+        delete_index_source_task(str(instance.pk))
+        verbose_name = _('Index media from source "{}"')
+        index_source_task(
+            str(instance.pk),
+            repeat=instance.index_schedule,
+            verbose_name=verbose_name.format(instance.name)
+        )
+
+
 @receiver(post_save, sender=Source)
 def source_post_save(sender, instance, created, **kwargs):
-    # Triggered when a source is saved, delete any source tasks that might exist
+    # Triggered after a source is saved
-    delete_index_source_task(str(instance.pk))
+    if created:
-    # Create a new scheduled indexing task as the repeat schedule may have changed
+        # Create a new indexing task for newly created sources
-    index_source_task(str(instance.pk), repeat=instance.index_schedule)
+        delete_index_source_task(str(instance.pk))
+        log.info(f'Scheduling media indexing for source: {instance.name}')
+        verbose_name = _('Index media from source "{}"')
+        index_source_task(
+            str(instance.pk),
+            repeat=instance.index_schedule,
+            verbose_name=verbose_name.format(instance.name)
+        )
 
 
 @receiver(pre_delete, sender=Source)
 def source_post_delete(sender, instance, **kwargs):
-    # Triggered just before a source is deleted, delete all media objects to trigger
+    # Triggered before a source is deleted, delete all media objects to trigger
     # the Media models post_delete signal
     for media in Media.objects.filter(source=instance):
+        log.info(f'Deleting media for source: {instance.name} item: {media.name}')
         media.delete()
 
 
 @receiver(post_delete, sender=Source)
 def source_post_delete(sender, instance, **kwargs):
-    # Triggered when a source is deleted
+    # Triggered after a source is deleted
+    log.info(f'Deleting tasks for source: {instance.name}')
     delete_index_source_task(str(instance.pk))
 
 
+@receiver(task_failed, sender=Task)
+def task_task_failed(sender, task_id, completed_task, **kwargs):
+    # Triggered after a source fails by reaching its max retry attempts
+    obj, url = map_task_to_instance(completed_task)
+    if isinstance(obj, Source):
+        log.error(f'Permanent failure for source: {obj} task: {completed_task}')
+        obj.has_failed = True
+        obj.save()
+
+
 @receiver(post_save, sender=Media)
 def media_post_save(sender, instance, created, **kwargs):
-    # Triggered when media is saved
+    # Triggered after media is saved
     if created:
         # If the media is newly created fire a task off to download its thumbnail
         metadata = instance.loaded_metadata
         thumbnail_url = metadata.get('thumbnail', '')
         if thumbnail_url:
-            download_media_thumbnail(str(instance.pk), thumbnail_url)
+            log.info(f'Scheduling task to download thumbnail for: {instance.name} '
+                     f'from: {thumbnail_url}')
+            verbose_name = _('Downloading media thumbnail for "{}')
+            download_media_thumbnail(
+                str(instance.pk),
+                thumbnail_url,
+                verbose_name=verbose_name.format(instance.name)
+            )
 
 
 @receiver(post_delete, sender=Media)
 def media_post_delete(sender, instance, **kwargs):
-    # Triggered when media is deleted, delete media thumbnail
+    # Triggered after media is deleted, delete media thumbnail
     if instance.thumb:
+        log.info(f'Deleting thumbnail for: {instance} path: {instance.thumb.path}')
         delete_file(instance.thumb.path)

app/sync/tasks.py

@@ -6,30 +6,109 @@
 
 import json
 import math
+import uuid
 from io import BytesIO
+from hashlib import sha1
+from datetime import timedelta
 from PIL import Image
 from django.conf import settings
 from django.core.files.uploadedfile import SimpleUploadedFile
 from django.utils import timezone
 from django.db.utils import IntegrityError
 from background_task import background
-from background_task.models import Task
+from background_task.models import Task, CompletedTask
 from common.logger import log
+from common.errors import NoMediaException
 from .models import Source, Media
 from .utils import get_remote_image, resize_image_to_height
 
 
-def delete_index_source_task(source_id):
+def get_hash(task_name, pk):
-    task = None
+    '''
+        Create a background_task compatible hash for a Task or CompletedTask.
+    '''
+    task_params = json.dumps(((str(pk),), {}), sort_keys=True)
+    return sha1(f'{task_name}{task_params}'.encode('utf-8')).hexdigest()
+
+
+def map_task_to_instance(task):
+    '''
+        Reverse-maps an scheduled backgrond task to an instance. Requires the task name
+        to be a known task function and the first argument to be a UUID. This is used
+        because UUID's are incompatible with background_task's "creator" feature.
+    '''
+    TASK_MAP = {
+        'sync.tasks.index_source_task': Source,
+        'sync.tasks.download_media_thumbnail': Media,
+    }
+    MODEL_URL_MAP = {
+        Source: 'sync:source',
+        Media: 'sync:media-item',
+    }
+    task_func, task_args_str = task.task_name, task.task_params
+    model = TASK_MAP.get(task_func, None)
+    if not model:
+        return None, None
+    url = MODEL_URL_MAP.get(model, None)
+    if not url:
+        return None, None
     try:
-        # get_task currently returns a QuerySet, but catch DoesNotExist just in case
+        task_args = json.loads(task_args_str)
-        task = Task.objects.get_task('sync.tasks.index_source_task', args=(source_id,))
+    except (TypeError, ValueError, AttributeError):
-    except Task.DoesNotExist:
+        return None, None
-        pass
+    if len(task_args) != 2:
-    if task:
+        return None, None
-        # A scheduled task exists for this Source, delete it
+    args, kwargs = task_args
-        log.info(f'Deleting Source index task: {task}')
+    if len(args) == 0:
-        task.delete()
+        return None, None
+    instance_uuid_str = args[0]
+    try:
+        instance_uuid = uuid.UUID(instance_uuid_str)
+    except (TypeError, ValueError, AttributeError):
+        return None, None
+    try:
+        instance = model.objects.get(pk=instance_uuid)
+        return instance, url
+    except model.DoesNotExist:
+        return None, None
+
+
+def get_error_message(task):
+    '''
+        Extract an error message from a failed task.
+    '''
+    if not task.has_error():
+        return ''
+    stacktrace_lines = task.last_error.strip().split('\n')
+    if len(stacktrace_lines) == 0:
+        return ''
+    error_message = stacktrace_lines[-1].strip()
+    if ':' not in error_message:
+        return ''
+    return error_message.split(':', 1)[1].strip()
+
+
+def get_source_completed_tasks(source_id, only_errors=False):
+    '''
+        Returns a queryset of CompletedTask objects for a source by source ID.
+    '''
+    source_hash = get_hash('sync.tasks.index_source_task', source_id)
+    q = {'task_hash': source_hash}
+    if only_errors:
+        q['failed_at__isnull'] = False
+    return CompletedTask.objects.filter(**q).order_by('-failed_at')
+
+
+def delete_index_source_task(source_id):
+    Task.objects.drop_task('sync.tasks.index_source_task', args=(source_id,))
+
+
+def cleanup_completed_tasks():
+    days_to_keep = getattr(settings, 'COMPLETED_TASKS_DAYS_TO_KEEP', 30)
+    delta = timezone.now() - timedelta(days=days_to_keep)
+    log.info(f'Deleting completed tasks older than {days_to_keep} days '
+             f'(run_at before {delta})')
+    CompletedTask.objects.filter(run_at__lt=delta).delete()
 
 
 @background(schedule=0)
@@ -43,7 +122,20 @@ def index_source_task(source_id):
         # Task triggered but the Source has been deleted, delete the task
         delete_index_source_task(source_id)
         return
+    # Reset any errors
+    source.has_failed = False
+    source.save()
+    # Index the source
     videos = source.index_media()
+    if not videos:
+        raise NoMediaException(f'Source "{source}" (ID: {source_id}) returned no '
+                               f'media to index, is the source key valid? Check the '
+                               f'source configuration is correct and that the source '
+                               f'is reachable')
+    # Got some media, update the last crawl timestamp
+    source.last_crawl = timezone.now()
+    source.save()
+    log.info(f'Found {len(videos)} media items for source: {source}')
     for video in videos:
         # Create or update each video as a Media object
         key = video.get(source.key_field, None)
@@ -64,6 +156,8 @@ def index_source_task(source_id):
             log.info(f'Indexed media: {source} / {media}')
         except IntegrityError as e:
             log.error(f'Index media failed: {source} / {media} with "{e}"')
+    # Tack on a cleanup of old completed tasks
+    cleanup_completed_tasks()
 
 
 @background(schedule=0)

app/sync/templates/sync/dashboard.html

@@ -3,6 +3,11 @@
 {% block headtitle %}Dashboard{% endblock %}
 
 {% block content %}
+<div class="row">
+  <div class="col s12">
+    <h1 class="truncate">Dashboard</h1>
+  </div>
+</div>
 <div class="row">
   <div class="col s12">
     <div class="card">

app/sync/templates/sync/media.html

@@ -3,6 +3,11 @@
 {% block headtitle %}Media{% if source %} - {{ source }}{% endif %}{% endblock %}
 
 {% block content %}
+<div class="row">
+  <div class="col s12">
+    <h1 class="truncate">Media</h1>
+  </div>
+</div>
 {% include 'infobox.html' with message=message %}
 <div class="row no-margin-bottom">
   {% for m in media %}
@@ -22,7 +27,7 @@
   {% empty %}
   <div class="col s12">
     <div class="collection">
-      <span class="collection-item no-items"><i class="fas fa-info-circle"></i> No media has been indexed.</span>
+      <span class="collection-item no-items"><i class="fas fa-info-circle"></i> No media has been indexed{% if source %} that matches the specified source filter{% endif %}.</span>
     </div>
   </div>
   {% endfor %}

app/sync/templates/sync/source.html

@@ -3,14 +3,22 @@
 {% block headtitle %}Source - {{ source.name }}{% endblock %}
 
 {% block content %}
-<div class="row">
+<div class="row no-margin-bottom">
   <div class="col s12">
     <h1 class="truncate">Source <strong>{{ source.name }}</strong></h1>
     <p class="truncate"><strong><a href="{{ source.url }}" target="_blank"><i class="fas fa-link"></i> {{ source.url }}</a></strong></p>
     <p class="truncate">Saving to: <strong>{{ source.directory_path }}</strong></p>
-    <p><a href="{% url 'sync:media' %}?filter={{ source.pk }}" class="btn">Media<span class="hide-on-small-only"> linked to this source</span> <i class="fas fa-fw fa-film"></i></a></p>
   </div>
 </div>
+<div class="row">
+  <div class="col s12 l6 margin-bottom">
+    <a href="{% url 'sync:media' %}?filter={{ source.pk }}" class="btn">View media<span class="hide-on-small-only"> linked to this source</span> <i class="fas fa-fw fa-film"></i></a>
+  </div>
+  <div class="col s12 l6 margin-bottom">
+    <a href="{% url 'sync:tasks-completed' %}?filter={{ source.pk }}" class="btn">View tasks<span class="hide-on-small-only"> linked to this source</span> <i class="far fa-fw fa-clock"></i></a>
+  </div>
+</div>
+{% if source.has_failed %}{% include 'errorbox.html' with message='This source has encountered permanent failures listed at the bottom of this page, check its settings' %}{% endif %}
 <div class="row">
   <div class="col s12">
     <table class="striped">
@@ -22,6 +30,10 @@
         <td class="hide-on-small-only">Name</td>
         <td><span class="hide-on-med-and-up">Name<br></span><strong>{{ source.name }}</strong></td>
       </tr>
+      <tr title="Number of media items downloaded for the source">
+        <td class="hide-on-small-only">Media items</td>
+        <td><span class="hide-on-med-and-up">Media items<br></span><strong><a href="{% url 'sync:media' %}?filter={{ source.pk }}">{{ media|length }}</a></strong></td>
+      </tr>
       <tr title="Unique key of the source, such as the channel name or playlist ID">
         <td class="hide-on-small-only">Key</td>
         <td><span class="hide-on-med-and-up">Key<br></span><strong>{{ source.key }}</strong></td>
@@ -98,4 +110,20 @@
     <a href="{% url 'sync:delete-source' pk=source.pk %}" class="btn delete-button">Delete source <i class="fas fa-trash-alt"></i></a>
   </div>
 </div>
+{% if errors %}
+<div class="row">
+  <div class="col s12">
+    <h2>Source has encountered {{ errors|length }} Error{{ errors|length|pluralize }}</h2>
+    <div class="collection">
+      {% for task in errors %}
+        <span class="collection-item error-text">
+          <i class="fas fa-exclamation-triangle"></i> <strong>{{ task.verbose_name }}</strong><br>
+          Error: &quot;{{ task.error_message }}&quot;<br>
+          <i class="far fa-clock"></i> Occured at <strong>{{ task.run_at|date:'Y-m-d H:i:s' }}</strong>
+        </span>
+      {% endfor %}
+    </div>
+  </div>
+</div>
+{% endif %}
 {% endblock %}

app/sync/templates/sync/sources.html

@@ -3,8 +3,13 @@
 {% block headtitle %}Sources{% endblock %}
 
 {% block content %}
+<div class="row">
+  <div class="col s12">
+    <h1 class="truncate">Sources</h1>
+  </div>
+</div>
 {% include 'infobox.html' with message=message %}
-<div class="row no-margin-bottom">
+<div class="row">
   <div class="col s12 l6 margin-bottom">
     <a href="{% url 'sync:validate-source' source_type='youtube-channel' %}" class="btn">Add a YouTube channel <i class="fab fa-youtube"></i></a>
   </div>
@@ -17,9 +22,13 @@
     <div class="collection">
     {% for source in sources %}
       <a href="{% url 'sync:source' pk=source.pk %}" class="collection-item">
-        {{ source.icon|safe }} <strong>{{ source.name }}</strong> ({{ source.get_source_type_display }})<br>
+        {{ source.icon|safe }} <strong>{{ source.name }}</strong> ({{ source.get_source_type_display }} &quot;{{ source.key }}&quot;)<br>
         {{ source.format_summary }}<br>
+        {% if source.has_failed %}
+        <span class="error-text"><i class="fas fa-exclamation-triangle"></i> <strong>Source has permanent failures</strong></span>
+        {% else %}
         <strong>{{ source.media_count }}</strong> media items{% if source.delete_old_media and source.days_to_keep > 0 %}, keep {{ source.days_to_keep }} days of media{% endif %}
+        {% endif %}
       </a>
     {% empty %}
       <span class="collection-item no-items"><i class="fas fa-info-circle"></i> You haven't added any sources.</span>

app/sync/templates/sync/tasks-completed.html

@@ -0,0 +1,33 @@
+{% extends 'base.html' %}
+
+{% block headtitle %}Tasks - Completed{% endblock %}
+
+{% block content %}
+<div class="row">
+  <div class="col s12">
+    <h1 class="truncate">Completed tasks</h1>
+  </div>
+</div>
+{% include 'infobox.html' with message=message %}
+<div class="row">
+  <div class="col s12">
+    <div class="collection">
+    {% for task in tasks %}
+      <span class="collection-item">
+      {% if task.has_error %}
+        <i class="fas fa-exclamation-triangle"></i> <strong>{{ task.verbose_name }}</strong><br>
+        Error: &quot;{{ task.error_message }}&quot;<br>
+        <i class="far fa-clock"></i> Task started at <strong>{{ task.run_at|date:'Y-m-d H:i:s' }}</strong>
+      {% else %}
+        <i class="fas fa-check"></i> <strong>{{ task.verbose_name }}</strong><br>
+        <i class="far fa-clock"></i> Task started at <strong>{{ task.run_at|date:'Y-m-d H:i:s' }}</strong>
+      {% endif %}
+      </span>
+    {% empty %}
+      <span class="collection-item no-items"><i class="fas fa-info-circle"></i> There have been no completed tasks.</span>
+    {% endfor %}
+    </div>
+  </div>
+</div>
+{% include 'pagination.html' with pagination=sources.paginator filter=source.pk %}
+{% endblock %}

app/sync/templates/sync/tasks.html

@@ -5,7 +5,83 @@
 {% block content %}
 <div class="row">
   <div class="col s12">
-    tasks
+    <h1>Tasks</h1>
+    <p>
+      Tasks are the background work that TubeSync undertakes to index and download
+      media. This page allows you to see basic overview of what is running and what is
+      scheduled to perform in the future as well as check up on any errors that might
+      have occured.
+    </p>
+  </div>
+</div>
+<div class="row">
+  <div class="col s12">
+    <h2>{{ running|length }} Running</h2>
+    <p>
+      Running tasks are tasks which currently being worked on right now.
+    </p>
+    <div class="collection">
+      {% for task in running %}
+        <a href="{% url task.url pk=task.instance.pk %}" class="collection-item">
+          <i class="fas fa-running"></i> <strong>{{ task }}</strong><br>
+          <i class="far fa-clock"></i> Task started at <strong>{{ task.run_at|date:'Y-m-d H:i:s' }}</strong>
+        </a>
+      {% empty %}
+        <span class="collection-item no-items"><i class="fas fa-info-circle"></i> There are no running tasks.</span>
+      {% endfor %}
+    </div>
+  </div>
+</div>
+<div class="row">
+  <div class="col s12">
+    <h2>{{ errors|length }} Error{{ errors|length|pluralize }}</h2>
+    <p>
+      Tasks which generated an error are shown here. Tasks are retried a couple of
+      times, so if there was an intermittent error such as a download got interrupted
+      it will be scheduled to run again.
+    </p>
+    <div class="collection">
+      {% for task in errors %}
+        <a href="{% url task.url pk=task.instance.pk %}" class="collection-item error-text">
+          <i class="fas fa-exclamation-triangle"></i> <strong>{{ task }}</strong>, attempted {{ task.attempts }} time{{ task.attempts|pluralize }}<br>
+          Error: &quot;{{ task.error_message }}&quot;<br>
+          <i class="fas fa-history"></i> Task will be retried at <strong>{{ task.run_at|date:'Y-m-d H:i:s' }}</strong>
+        </a>
+      {% empty %}
+        <span class="collection-item no-items"><i class="fas fa-info-circle"></i> There are no tasks with errors.</span>
+      {% endfor %}
+    </div>
+  </div>
+</div>
+<div class="row">
+  <div class="col s12">
+    <h2>{{ scheduled|length }} Scheduled</h2>
+    <p>
+      Tasks which are scheduled to run in the future or are waiting in a queue to be
+      processed. They can be waiting for an available worker to run immediately, or
+      run in the future at the specified &quot;run at&quot; time.
+    </p>
+    <div class="collection">
+      {% for task in scheduled %}
+        <a href="{% url task.url pk=task.instance.pk %}" class="collection-item">
+          <i class="far fa-stopwatch"></i> <strong>{{ task }}</strong><br>
+          Scheduled to run {{ task.instance.get_index_schedule_display|lower }}.<br>
+          <i class="fas fa-redo"></i> Task will run at <strong>{{ task.run_at|date:'Y-m-d H:i:s' }}</strong>
+        </a>
+      {% empty %}
+        <span class="collection-item no-items"><i class="fas fa-info-circle"></i> There are no scheduled tasks.</span>
+      {% endfor %}
+    </div>
+  </div>
+</div>
+<div class="row">
+  <div class="col s12">
+    <h2>Completed</h2>
+    <p>
+      A record of recently completed tasks is kept for a few days. You can use the button
+      below to view recent tasks which have completed successfully.
+    </p>
+    <a href="{% url 'sync:tasks-completed' %}" class="btn"><span class="hide-on-med-and-down">View </span>Completed tasks <i class="fas fa-check-double"></i></a>
   </div>
 </div>
 {% endblock %}

app/sync/urls.py

@@ -1,7 +1,7 @@
 from django.urls import path
 from .views import (DashboardView, SourcesView, ValidateSourceView, AddSourceView,
                     SourceView, UpdateSourceView, DeleteSourceView, MediaView,
-                    MediaThumbView, MediaItemView, TasksView)
+                    MediaThumbView, MediaItemView, TasksView, CompletedTasksView)
 
 
 app_name = 'sync'
@@ -61,4 +61,8 @@ urlpatterns = [
          TasksView.as_view(),
          name='tasks'),
 
+    path('tasks-completed',
+         CompletedTasksView.as_view(),
+         name='tasks-completed'),
+
 ]

app/sync/utils.py

@@ -14,25 +14,31 @@ def validate_url(url, validator):
         Validate a URL against a dict of validation requirements. Returns an extracted
         part of the URL if the URL is valid, if invalid raises a ValidationError.
     '''
-    valid_scheme, valid_netloc, valid_path, valid_query, extract_parts = (
+    valid_scheme, valid_netloc, valid_path, invalid_paths, valid_query, \
-        validator['scheme'], validator['domain'], validator['path_regex'],
+        extract_parts = (
-        validator['qs_args'], validator['extract_key'])
+            validator['scheme'], validator['domain'], validator['path_regex'],
+            validator['path_must_not_match'], validator['qs_args'],
+            validator['extract_key']
+    )
     url_parts = urlsplit(str(url).strip())
     url_scheme = str(url_parts.scheme).strip().lower()
     if url_scheme != valid_scheme:
-        raise ValidationError(f'scheme "{url_scheme}" must be "{valid_scheme}"')
+        raise ValidationError(f'invalid scheme "{url_scheme}" must be "{valid_scheme}"')
     url_netloc = str(url_parts.netloc).strip().lower()
     if url_netloc != valid_netloc:
-        raise ValidationError(f'domain "{url_netloc}" must be "{valid_netloc}"')
+        raise ValidationError(f'invalid domain "{url_netloc}" must be "{valid_netloc}"')
     url_path = str(url_parts.path).strip()
     matches = re.findall(valid_path, url_path)
     if not matches:
-        raise ValidationError(f'path "{url_path}" must match "{valid_path}"')
+        raise ValidationError(f'invalid path "{url_path}" must match "{valid_path}"')
+    for invalid_path in invalid_paths:
+        if url_path.lower() == invalid_path.lower():
+            raise ValidationError(f'path "{url_path}" is not valid')
     url_query = str(url_parts.query).strip()
     url_query_parts = parse_qs(url_query)
     for required_query in valid_query:
         if required_query not in url_query_parts:
-            raise ValidationError(f'query string "{url_query}" must '
+            raise ValidationError(f'invalid query string "{url_query}" must '
                                   f'contain the parameter "{required_query}"')
     extract_from, extract_param = extract_parts
     extract_value = ''
@@ -76,7 +82,7 @@ def resize_image_to_height(image, width, height):
     if scaled_width > width:
         # Width too large, crop it
         delta = scaled_width - width
-        left, upper = (delta / 2), 0
+        left, upper = round(delta / 2), 0
         right, lower = (left + width), height
         image = image.crop((left, upper, right, lower))
     return image

app/sync/views.py

@@ -9,11 +9,14 @@ from django.urls import reverse_lazy
 from django.db.models import Count
 from django.forms import ValidationError
 from django.utils.text import slugify
+from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 from common.utils import append_uri_params
+from background_task.models import Task, CompletedTask
 from .models import Source, Media
 from .forms import ValidateSourceForm, ConfirmDeleteSourceForm
 from .utils import validate_url
+from .tasks import map_task_to_instance, get_error_message, get_source_completed_tasks
 from . import signals
 from . import youtube
 
@@ -108,6 +111,7 @@ class ValidateSourceView(FormView):
             'scheme': 'https',
             'domain': 'www.youtube.com',
             'path_regex': '^\/(c\/)?([^\/]+)$',
+            'path_must_not_match': ('/playlist',),
             'qs_args': [],
             'extract_key': ('path_regex', 1),
             'example': 'https://www.youtube.com/SOMECHANNEL'
@@ -116,7 +120,8 @@ class ValidateSourceView(FormView):
             'scheme': 'https',
             'domain': 'www.youtube.com',
             'path_regex': '^\/(playlist|watch)$',
-            'qs_args': ['list'],
+            'path_must_not_match': (),
+            'qs_args': ('list',),
             'extract_key': ('qs_args', 'list'),
             'example': 'https://www.youtube.com/playlist?list=PLAYLISTID'
         },
@@ -239,6 +244,16 @@ class SourceView(DetailView):
     template_name = 'sync/source.html'
     model = Source
 
+    def get_context_data(self, *args, **kwargs):
+        data = super().get_context_data(*args, **kwargs)
+        data['errors'] = []
+        for error in get_source_completed_tasks(self.object.pk, only_errors=True):
+            error_message = get_error_message(error)
+            setattr(error, 'error_message', error_message)
+            data['errors'].append(error)
+        data['media'] = Media.objects.filter(source=self.object).order_by('-published')
+        return data
+
 
 class UpdateSourceView(UpdateView):
 
@@ -286,7 +301,7 @@ class MediaView(ListView):
     context_object_name = 'media'
     paginate_by = settings.MEDIA_PER_PAGE
     messages = {
-        'filter': _('Viewing media for source: <strong>{name}</strong>'),
+        'filter': _('Viewing media filtered for source: <strong>{name}</strong>'),
     }
 
     def __init__(self, *args, **kwargs):
@@ -352,13 +367,90 @@ class MediaItemView(DetailView):
     model = Media
 
 
-class TasksView(TemplateView):
+class TasksView(ListView):
     '''
         A list of tasks queued to be completed. Typically, this is scraping for new
         media or downloading media.
     '''
 
     template_name = 'sync/tasks.html'
+    context_object_name = 'tasks'
+
+    def get_queryset(self):
+        return Task.objects.all().order_by('run_at')
+
+    def get_context_data(self, *args, **kwargs):
+        data = super().get_context_data(*args, **kwargs)
+        data['running'] = []
+        data['errors'] = []
+        data['scheduled'] = []
+        queryset = self.get_queryset()
+        now = timezone.now()
+        for task in queryset:
+            obj, url = map_task_to_instance(task)
+            if not obj:
+                # Orphaned task, ignore it (it will be deleted when it fires)
+                continue
+            setattr(task, 'instance', obj)
+            setattr(task, 'url', url)
+            if task.locked_by_pid_running():
+                data['running'].append(task)
+            elif task.has_error():
+                error_message = get_error_message(task)
+                setattr(task, 'error_message', error_message)
+                data['errors'].append(task)
+            else:
+                data['scheduled'].append(task)
+        return data
+
+
+class CompletedTasksView(ListView):
+    '''
+        List of tasks which have been completed with an optional per-source filter.
+    '''
+
+    template_name = 'sync/tasks-completed.html'
+    context_object_name = 'tasks'
+    paginate_by = settings.TASKS_PER_PAGE
+    messages = {
+        'filter': _('Viewing tasks filtered for source: <strong>{name}</strong>'),
+    }
+
+    def __init__(self, *args, **kwargs):
+        self.filter_source = None
+        super().__init__(*args, **kwargs)
 
     def dispatch(self, request, *args, **kwargs):
+        filter_by = request.GET.get('filter', '')
+        if filter_by:
+            try:
+                self.filter_source = Source.objects.get(pk=filter_by)
+            except Source.DoesNotExist:
+                self.filter_source = None
         return super().dispatch(request, *args, **kwargs)
+
+    def get_queryset(self):
+        return CompletedTask.objects.all().order_by('-run_at')
+
+    def get_queryset(self):
+        if self.filter_source:
+            return CompletedTask.objects.all().order_by('-run_at')
+            #tasks = []
+            #for task in CompletedTask.objects.all().order_by('-run_at'):
+            #    # ???
+            #q = Media.objects.filter(source=self.filter_source)
+        return CompletedTask.objects.all().order_by('-run_at')
+
+    def get_context_data(self, *args, **kwargs):
+        data = super().get_context_data(*args, **kwargs)
+        for task in data['tasks']:
+            if task.has_error():
+                error_message = get_error_message(task)
+                setattr(task, 'error_message', error_message)
+        data['message'] = ''
+        data['source'] = None
+        if self.filter_source:
+            message = str(self.messages.get('filter', ''))
+            data['message'] = message.format(name=self.filter_source.name)
+            data['source'] = self.filter_source
+        return data

app/tubesync/local_settings.py.container

@@ -1,13 +1,15 @@
 import os
 from pathlib import Path
+from 
 
 
 BASE_DIR = Path(__file__).resolve().parent.parent
 ROOT_DIR = Path('/')
 
 
-SECRET_KEY = str(os.getenv('DJANGO_SECRET_KEY', ''))
+RANDOM_SECRET = hexlify(os.urandom(32)).decode()
-ALLOWED_HOSTS_STR = str(os.getenv('DJANGO_ALLOWED_HOSTS', ''))
+SECRET_KEY = str(os.getenv('DJANGO_SECRET_KEY', RANDOM_SECRET))
+ALLOWED_HOSTS_STR = str(os.getenv('TUBESYNC_HOSTS', 'localhost'))
 ALLOWED_HOSTS = ALLOWED_HOSTS_STR.split(',')
 
 
@@ -19,6 +21,9 @@ DATABASES = {
 }
 
 
+BACKGROUND_TASK_ASYNC_THREADS = int(os.get('TUBESYNC_WORKERS', 2))
+
+
 MEDIA_ROOT = ROOT_DIR / 'config' / 'media'
 SYNC_VIDEO_ROOT = ROOT_DIR / 'downloads' / 'video'
 SYNC_AUDIO_ROOT = ROOT_DIR / 'downloads' / 'audio'

app/tubesync/settings.py

@@ -118,10 +118,12 @@ MAX_RUN_TIME = 1800                         # Maximum amount of time in seconds
 BACKGROUND_TASK_RUN_ASYNC = True            # Run tasks async in the background
 BACKGROUND_TASK_ASYNC_THREADS = 2           # Number of async tasks to run at once
 BACKGROUND_TASK_PRIORITY_ORDERING = 'DESC'  # Process high priority tasks first
+COMPLETED_TASKS_DAYS_TO_KEEP = 30            # Number of days to keep completed tasks
 
 
 SOURCES_PER_PAGE = 36
 MEDIA_PER_PAGE = 36
+TASKS_PER_PAGE = 100
 
 
 MEDIA_THUMBNAIL_WIDTH = 430                 # Width in pixels to resize thumbnails to