Merge pull request #85 from tecladocode/jose/cou-158-rest-add-lecture-on-deploying-rq-worker

Author: jslvtr

docs/docs/12_task_queues_emails/07_deploy_background_worker_render/README.md

@@ -0,0 +1,47 @@
+# Deploy the rq background worker to Render.com
+
+When deploying to Render.com, it's much easier if we don't have to pass the `REDIS_URL` and the queue name directly to the command.
+
+So instead, let's create a `settings.py` file and put our `rq` worker configuration there:
+
+```python title="settings.py"
+import os
+from dotenv import load_dotenv
+
+load_dotenv()
+
+REDIS_URL = os.getenv("REDIS_URL", "redis://localhost:6379")
+QUEUES = ["emails", "default"]
+```
+
+The names of the variables are important, see [the documentation](https://python-rq.org/docs/workers/#using-a-config-file) for all the options that are currently supported.
+
+To run the `rq` worker using this settings file use `rq worker -c settings`.
+
+Let's add this to our repo, and then deploy the background worker to Render.com.
+
+First create a new background worker:
+
+![Create a new service of type background worker in Render.com](./assets/render-create-bg-worker.png)
+
+Then, give it a name and fill in its basic settings. The default works for the most part. Make sure it's in the same region as or close to your Postgres and Redis databases:
+
+![Filling in the Render basic worker information with its name set to 'rest-api-background-worker', environment set to 'docker', and region set to 'Frankfurt'](./assets/render-bg-worker-basic-settings.png)
+
+Add the environment variables it needs. Although in this case it doesn't need the `DATABASE_URL`, you can add it if you will be adding other tasks that do use the database in the near future. If not, leave it out.
+
+:::warning Internal URL
+If your Redis database is with Render.com, you'd want to use the Redis database **Internal URL**, but I encountered some issues with it where the `redis` package didn't recognise the URL. Try it, but fall back to the external URL if it doesn't work.
+:::
+
+![Environment variables added in Render.com including DATABASE_URL, REDIS_URL, MAILGUN_API_KEY, and MAILGUN_DOMAIN, with their respective values](./assets/render-bg-worker-env-vars.png)
+
+Finally, this "background worker" is just a Python program without networking capabilities. So if we leave it as is, it will actually just run our Dockerfile and the Dockerfile's `CMD` command (which starts our web application). Therefore we want to give it a custom Docker command that starts the background worker.
+
+In that command, I'll go into the `/app` directory of the Docker container, and run the `rq` worker passing in the `settings.py` file.
+
+The command is `/bin/bash -c cd /app && rq worker -c settings`.
+
+This is what it looks like in Render.com:
+
+![Screenshot showing the Docker command in Render.com](./assets/render-bg-worker-docker-command.png)

docs/docs/12_task_queues_emails/07_deploy_background_worker_render/assets/render-bg-worker-basic-settings.png

@@ -0,0 +1,4 @@
+DATABASE_URL=
+MAILGUN_API_KEY=
+MAILGUN_DOMAIN=
+REDIS_URL=

docs/docs/12_task_queues_emails/07_deploy_background_worker_render/assets/render-bg-worker-docker-command.png

@@ -0,0 +1,2 @@
+FLASK_APP=app
+FLASK_DEBUG=True

docs/docs/12_task_queues_emails/07_deploy_background_worker_render/assets/render-bg-worker-env-vars.png

@@ -0,0 +1,7 @@
+.env
+.venv
+.vscode
+__pycache__
+data.db
+*.pyc
+.DS_Store

docs/docs/12_task_queues_emails/07_deploy_background_worker_render/assets/render-create-bg-worker.png

@@ -0,0 +1 @@
+3.10.6

docs/docs/12_task_queues_emails/07_deploy_background_worker_render/end/.env.example

@@ -0,0 +1,7 @@
+# CONTRIBUTING
+
+## How to run the Dockerfile locally
+
+```
+docker run -dp 5000:5000 -w /app -v "$(pwd):/app" IMAGE_NAME sh -c "flask run"
+```