From 6986fc90251c3cf2f991760568546cafc1cab335 Mon Sep 17 00:00:00 2001
From: Wesley Aptekar-Cassels <me@wesleyac.com>
Date: Thu, 6 Apr 2023 05:48:24 -0400
Subject: [PATCH] Add form to remove tasks from Celery

---
 bookwyrm/templates/settings/celery.html | 29 ++++++++++++++
 bookwyrm/views/admin/celery_status.py   | 50 +++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/bookwyrm/templates/settings/celery.html b/bookwyrm/templates/settings/celery.html
index 65315da01..5f79dfd9d 100644
--- a/bookwyrm/templates/settings/celery.html
+++ b/bookwyrm/templates/settings/celery.html
@@ -116,6 +116,35 @@
 </div>
 {% endif %}
 
+<section class="block">
+    <div class="content"><h2>{% trans "Clear Queues" %}</h2></div>
+
+    <div class="content notification is-warning is-flex is-align-items-start">
+        <span class="icon icon-warning is-size-4 pr-3" aria-hidden="true"></span>
+        {% trans "Clearing queues can cause serious problems including data loss! Only play with this if you really know what you're doing. You must shut down the Celery worker before you do this." %}
+    </div>
+
+    <form action="{% url 'settings-celery' %}" method="post">
+        {% csrf_token %}
+
+        <div class="columns">
+            <div class="column is-3">
+                <div class="content"><h3>{{ form.queues.label_tag }}</h3></div>
+                {{ form.queues }}
+            </div>
+
+            <div class="column is-9">
+                <div class="content"><h3>{{ form.tasks.label_tag }}</h3></div>
+                {{ form.tasks }}
+            </div>
+        </div>
+
+        <div class="buttons is-right">
+            <button type="submit" class="button is-danger">{% trans "Clear Queues" %}</button>
+        </div>
+    </form>
+</section>
+
 {% if errors %}
 <div class="block content">
     <h2>{% trans "Errors" %}</h2>
diff --git a/bookwyrm/views/admin/celery_status.py b/bookwyrm/views/admin/celery_status.py
index e0b1fe18c..392d7c471 100644
--- a/bookwyrm/views/admin/celery_status.py
+++ b/bookwyrm/views/admin/celery_status.py
@@ -1,10 +1,13 @@
 """ celery status """
+import json
+
 from django.contrib.auth.decorators import login_required, permission_required
 from django.http import HttpResponse
 from django.template.response import TemplateResponse
 from django.utils.decorators import method_decorator
 from django.views import View
 from django.views.decorators.http import require_GET
+from django import forms
 import redis
 
 from celerywyrm import settings
@@ -46,14 +49,61 @@ class CeleryStatus(View):
             queues = None
             errors.append(err)
 
+        form = ClearCeleryForm()
+
         data = {
             "stats": stats,
             "active_tasks": active_tasks,
             "queues": queues,
+            "form": form,
             "errors": errors,
         }
         return TemplateResponse(request, "settings/celery.html", data)
 
+    def post(self, request):
+        """Submit form to clear queues"""
+        form = ClearCeleryForm(request.POST)
+        if form.is_valid():
+            if len(celery.control.ping()) != 0:
+                return HttpResponse(
+                    "Refusing to delete tasks while Celery worker is active"
+                )
+            pipeline = r.pipeline()
+            for queue in form.cleaned_data["queues"]:
+                for task in r.lrange(queue, 0, -1):
+                    task_json = json.loads(task)
+                    if task_json["headers"]["task"] in form.cleaned_data["tasks"]:
+                        pipeline.lrem(queue, 0, task)
+            results = pipeline.execute()
+
+        return HttpResponse(f"Deleted {sum(results)} tasks")
+
+
+class ClearCeleryForm(forms.Form):
+    """Form to clear queues"""
+
+    queues = forms.MultipleChoiceField(
+        label="Queues",
+        choices=[
+            (LOW, "Low prioirty"),
+            (MEDIUM, "Medium priority"),
+            (HIGH, "High priority"),
+            (IMPORTS, "Imports"),
+            (BROADCAST, "Broadcasts"),
+        ],
+        widget=forms.CheckboxSelectMultiple,
+    )
+    tasks = forms.MultipleChoiceField(
+        label="Tasks", choices=[], widget=forms.CheckboxSelectMultiple
+    )
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        celery.loader.import_default_modules()
+        self.fields["tasks"].choices = sorted(
+            [(k, k) for k in celery.tasks.keys() if not k.startswith("celery.")]
+        )
+
 
 @require_GET
 # pylint: disable=unused-argument