inngest 0.3.2

Python SDK for Inngest

Serverless event-driven queues, background jobs, and scheduled jobs for Python.
Works with any framework and platform.

Read the documentation and get started in minutes.

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Inngest Python SDK

🚧 Currently in beta! Users have deployed our Python SDK in their production environments but it isn't as battle-tested as our TypeScript SDK.

We currently support the following frameworks (but adding a new framework is easy!):

• Django
• FastAPI
• Flask
• Tornado

Getting started

Install inngest in your project:

pip install inngest

Write a basic function and serve it (see the basic example for guidance).

Start the Dev Server (the local version of our cloud platform):

npx inngest-cli@latest dev

Browse to http://127.0.0.1:8288 and you should see your app! Visit our docs to read more about the Dev Server.

Examples

💡 You can mix async and non-async functions in the same app!

• Basic
• Step run
• Async function

Basic (no steps)

This is a minimal example of an Inngest function. It's missing some of our features but it's a good starting point.

import flask
import inngest.flask
import requests

inngest_client = inngest.Inngest(
    app_id="flask_example",
    is_production=False,
)

@inngest_client.create_function(
    fn_id="find_person",
    trigger=inngest.TriggerEvent(event="app/person.find"),
)
def fetch_person(
    ctx: inngest.Context,
    step: inngest.StepSync,
) -> dict:
    person_id = ctx.event.data["person_id"]
    res = requests.get(f"https://swapi.dev/api/people/{person_id}")
    return res.json()

app = flask.Flask(__name__)

# Register functions with the Inngest server
inngest.flask.serve(
    app,
    inngest_client,
    [fetch_person],
)

app.run(port=8000)

Send the following event in the Dev Server UI and the fetch_person function will run:

{
  "name": "app/person.find",
  "data": {
    "person_id": 1
  }
}

Step run

The following example registers a function that will:

1. Get the person ID from the event
2. Fetch the person with that ID
3. Fetch the person's ships
4. Return a summary dict

@inngest_client.create_function(
    fn_id="find_ships",
    trigger=inngest.TriggerEvent(event="app/ships.find"),
)
def fetch_ships(
    ctx: inngest.Context,
    step: inngest.StepSync,
) -> dict:
    """
    Find all the ships a person has.
    """

    person_id = ctx.event.data["person_id"]

    def _fetch_person() -> dict:
        res = requests.get(f"https://swapi.dev/api/people/{person_id}")
        return res.json()

    # Wrap the function with step.run to enable retries
    person = step.run("fetch_person", _fetch_person)

    def _fetch_ship(url: str) -> dict:
        res = requests.get(url)
        return res.json()

    ship_names = []
    for ship_url in person["starships"]:
        # step.run works in loops!
        ship = step.run("fetch_ship", lambda: _fetch_ship(ship_url))

        ship_names.append(ship["name"])

    return {
        "person_name": person["name"],
        "ship_names": ship_names,
    }

Send the following event in the Dev Server UI and the fetch_person function will run:

{
  "name": "app/ships.find",
  "data": {
    "person_id": 1
  }
}

Async function

@inngest_client.create_function(
    fn_id="find_person",
    trigger=inngest.TriggerEvent(event="app/person.find"),
)
async def fetch_person(
    ctx: inngest.Context,
    step: inngest.Step,
) -> dict:
    person_id = ctx.event.data["person_id"]
    async with httpx.AsyncClient() as client:
        res = await client.get(f"https://swapi.dev/api/people/{person_id}")
        return res.json()

Sending an event outside a function

Sometimes you want to send an event from a normal, non-Inngest function. You can do that using the client:

inngest_client.send_sync(inngest.Event(name="app/test", data={"person_id": 1}))

If you prefer async then use the send method instead:

await inngest_client.send(inngest.Event(name="app/test", data={"person_id": 1}))

Using in production

The Dev Server is not used in production. Inngest Cloud is used instead.

The INNGEST_EVENT_KEY and INNGEST_SIGNING_KEY environment variables must be set. These secrets establish trust between Inngest Cloud and your app. We also use request signature verification to mitigate man-in-the-middle attacks. You can read more about environment variables in our docs.

Your Inngest client must be in production mode. This is typically done with an environment variable:

inngest_client = inngest.Inngest(
    app_id="my_app",
    is_production=os.getenv("INNGEST_DEV") is None,
)