---
title: Empowering Django with Background Workers
class: text-center
highlighter: shiki
transition: slide-left
mdc: true
monaco: false
themeConfig:
  primary: '#0c4b33'
---

# Empowering Django with Background Workers

### Jake Howard{style="color: #e85537;" }

<ul class="list-none! text-sm [&>li]:m-0! mt-1 uppercase">
  <li>Senior Systems Engineer @ Torchbox <mdi-fire class="fill-white"/></li>
  <li>Security & Performance @ Wagtail <logos-wagtail class="fill-white"/></li>
</ul>

<ul class="list-none! text-xs [&>li]:m-0! mt-3 font-light">
  <li><mdi-earth /> theorangeone.net</li>
  <li><mdi-twitter /> @RealOrangeOne</li>
  <li><mdi-github /> @RealOrangeOne</li>
  <li><mdi-mastodon /> @jake@theorangeone.net</li>
</ul>

---
layout: center
---

# Django isn't _just_ for websites


```mermaid
flowchart LR
    U(User 🧑‍💻)
    D[\Django/]

    U---->|Request|D
    D---->|Response|U
```

<style>
  .mermaid {
    margin-top: 2rem;
    text-align: center;
    transform: scale(1.5);
  }
</style>

---
layout: full
---

```mermaid
flowchart BT
    U[User 🧑‍💻]
    D[\Django/]
    DB[(Database)]
    C[(Cache)]
    E>Email]
    EA[External API]
    V[[Video Transcode]]
    ML((Machine Learning))

    U---->|Request|D
    D---->|Response|U

    D-.-DB & E & EA & V & ML & C
```

---
layout: full
---

```mermaid
flowchart BT
    U[User 🧑‍💻]
    D[\Django/]
    DB[(Database)]
    C[(Cache)]
    E>Email]
    EA[External API]
    V[[Video Transcode]]
    ML((Machine Learning))
    B{{Background Processing}}

    U--->|Request|D
    D--->|Response|U

    D---B

    D-.-C & DB

    B---E & V & ML & EA
    B---C & DB
```

---
layout: cover
---

# Background Workers?

---
layout: fact
---

```mermaid
flowchart LR
    D[\Django/]
    S[(Queue Store)]
    R1{Runner}
    R2{Runner}
    R3{Runner}

    D<--->S<-..->R1 & R2 & R3
```

---
layout: cover
---

# When?

---
layout: fact
---



```mermaid
flowchart BT
    D[\Django/]

    subgraph Fast & Reliable
      DB[(Database)]
      C[(Cache)]
    end

    subgraph Slow / Unreliable
      E>Email]
      EA[External API]
      V[[Video Transcode]]
      ML((Machine Learning))
    end

    D---DB & C

    D-.-E & EA & V & ML
```

---
layout: cover
---

# Background Workers _in Django_

---
layout: cover
background: https://docs.celeryq.dev/en/stable/_static/celery_512.png
---

# Celery!

<style>
.slidev-layout {
    background: white;
}
</style>

---
layout: image-right
image: https://images.unsplash.com/photo-1444703686981-a3abbc4d4fe3?q=80&w=1740&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D
---

# Others...

<Transform :scale="1.05">

- ~~Celery~~
- arq
- Django DB Queue
- Django Lightweight Queue
- Django Too Simple Q
- Django-Q
- Django-Q2
- Dramatiq
- Huey
- RQ
- Taskiq
- ...

</Transform>

---
layout: cover
background: https://images.unsplash.com/photo-1522096823084-2d1aa8411c13?q=80&w=1740&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D
---

# Email <mdi-email-fast-outline />

---
layout: none
---

```python {all|8|9-14|16-19|all}
from django.contrib.auth.models import User
from django.core.mail import send_mail
from django.template.loader import render_to_string

import django_rq

def send_email_to_user(user: User):
    email_content = render_to_string("email-template.html", {"user": user})
    send_mail(
      subject="Here is your important customized message",
      message=email_content
      from_email=None,  # Use the default sender email
      recipient_list=[user.email]
    )

users_to_email = User.objects.all()

for user in users_to_email.iterator():
    django_rq.enqueue(send_email_to_user, user)
```

<style>
.slidev-page, .slidev-code-wrapper, .slidev-code {
  height: 100%;
}
</style>

---
layout: center
---

# A problem

````md magic-move
```python
from django.contrib.auth.models import User
from django.core.mail import send_mail
from django.template.loader import render_to_string

import django_rq

def send_email_to_user(user: User):
    email_content = render_to_string("email-template.html", {"user": user})
    send_mail(
      subject="Here is your important customized message",
      message=email_content
      from_email=None,  # Use the default sender email
      recipient_list=[user.email]
    )

users_to_email = User.objects.all()

for user in users_to_email.iterator():
    django_rq.enqueue(send_email_to_user, user)
```

```python {all|5-7,20|all}
from django.contrib.auth.models import User
from django.core.mail import send_mail
from django.template.loader import render_to_string

from my_celery_config import app

@app.task
def send_email_to_user(user: User):
    email_content = render_to_string("email-template.html", {"user": user})
    send_mail(
      subject="Here is your important customized message",
      message=email_content
      from_email=None,  # Use the default sender email
      recipient_list=[user.email]
    )

users_to_email = User.objects.all()

for user in users_to_email.iterator():
    send_email_to_user.delay(user)
```
````

---
layout: fact
---

# Situation:
## There are _14_ competing standards.

<style>
.slidev-layout {
    background: white;
    color: black;
}
</style>

---
layout: image-right
image: https://images.unsplash.com/photo-1674027444485-cec3da58eef4?q=80&w=1932&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D
class: flex items-center text-2xl
---

- Application developers
- Library maintainers
- System Engineers

---
layout: image
image: /ridiculous.png
class: bg-top!
---

# Ridiculous!

---
layout: fact
---

## Introducing:{.mb-5}

# `django.tasks`

---
layout: center
---

````md magic-move
```python
from django.contrib.auth.models import User
from django.core.mail import send_mail
from django.template.loader import render_to_string

from my_celery_config import app

@app.task
def send_email_to_user(user: User):
    email_content = render_to_string("email-template.html", {"user": user})
    send_mail(
      subject="Here is your important customized message",
      message=email_content
      from_email=None,  # Use the default sender email
      recipient_list=[user.email]
    )

users_to_email = User.objects.all()

for user in users_to_email.iterator():
    send_email_to_user.delay(user)
```

```python {all|5-7,20|all}
from django.contrib.auth.models import User
from django.core.mail import send_mail
from django.template.loader import render_to_string

from django.tasks import task

@task()
def send_email_to_user(user: User):
    email_content = render_to_string("email-template.html", {"user": user})
    send_mail(
      subject="Here is your important customized message",
      message=email_content
      from_email=None,  # Use the default sender email
      recipient_list=[user.email]
    )

users_to_email = User.objects.all()

for user in users_to_email.iterator():
    send_email_to_user.enqueue(user)
```
````

---
layout: center
---

```python
from django.contrib.auth.models import User
from django.core.mail import send_mail
from django.template.loader import render_to_string

users_to_email = User.objects.all()

email_content = render_to_string("email-template.html")

for user in users_to_email.iterator():
    send_mail(
      subject="Here is your important message",
      message=email_content
      from_email=None,  # Use the default sender email
      recipient_list=[user.email]
    )
```

<v-click>

```python
# settings.py
EMAIL_BACKEND = "django.core.mail.backends.tasks.SMTPEmailBackend"
```

</v-click>


---
layout: image-right
image: /soon.png
class: flex justify-center text-2xl flex-col
---

# Q: Why something new?

<v-click>

### A: We're not

</v-click>

---
layout: center
---

# Why something built-in?

<Transform :scale="1.3">
<v-clicks>

- Reduces barrier to entry
- Improve interoperability
- Reduce cognitive load

</v-clicks>
</Transform>

---
layout: section
---

# Where are we now?

<v-click>

## `pip install django-tasks`

</v-click>

---
layout: section
---

# Where are we going?

---
layout: image-right
image: https://images.unsplash.com/photo-1451187580459-43490279c0fa?q=80&w=1744&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D
class: flex justify-center flex-col text-xl
---

# Out of scope

- Completion / failed hooks
- Bulk queueing
- Automated task retrying
- Task runner API
- Unified observability
- Cron-based scheduling
- Task timeouts
- Swappable argument serialization

---
layout: section
---

# What's next?

---
layout: end
---