Write your session backend code and Dockerfile

Let's create the following files for our session backend in a directory called app.

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
 
app = FastAPI()
 
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
)
 
@app.get("/")
async def read_root():
    return {"res": "Hello World"}

fastapi==0.108.0
uvicorn==0.25.0

To package your session backend into a container, write a Dockerfile that Jamsocket can use to build and push your session backend code.

FROM python:3.9.6-slim
WORKDIR /app
COPY . .
RUN pip install -r requirements.txt
CMD ["uvicorn", "app:app", "--host", "0.0.0.0", "--port", "8080"]

Developing your code locally

Run the Dev CLI

npx jamsocket dev --dockerfile ./Dockerfile --watch .

npx jamsocket dev will start a Jamsocket dev server at localhost:8080. Check out the Dev CLI for more details on how the Dev CLI works.

Connect to a session backend

Get a Connection URL

To connect to your session backend, use the Jamsocket HTTP API or client libraries to get a connection URL.

Try making a curl request to the connect endpoint from the HTTP API:

curl -X POST http://localhost:8080/v2/service/MY_ACCOUNT/MY_SERVICE/connect

A successful JSON response will include a connection url. Use this URL to access your session backend API.

{
  "backend_id": "ebb8ljmndix2ge",
  "spawned": true,
  "status": "scheduled"
  "token": "ClpYXET8OA-ie7ufWFHE5y0Q-NbghE04niQ2fwBZe40",
  "url": "http://localhost:9090/ClpYXET8OA-ie7ufWFHE5y0Q-NbghE04niQ2fwBZe40/",
  "secret_token": "129aky7mT0ym-x0w5I88eTn41FFJawYwV4EgabC4r12",
  "status_url": "http://localhost:8080/v2/backend/ebb8ljmndix2ge/status",
  "ready_url": ""
}

Connect to your session backend API

When the backend returned from the connect endpoint shows a Ready status, make a curl request to an endpoint in your session backend api using the connection url.

A GET request to / should return the Hello World string from the backend.

curl CONNECTION_URL_FROM_SPAWN_REQUEST

Deploy to Jamsocket

Login to Jamsocket

npx jamsocket login

Create a service

npx jamsocket service create my-hello-world

You should see the service appear on your Jamsocket dashboard (opens in a new tab).

Build and push your session backend code to Jamsocket

You can build your session backend docker image and push to Jamsocket's container registry with a single command:

npx jamsocket push my-hello-world --dockerfile ./Dockerfile

Connect to session backends in production

To use the HTTP API in production, create an API token from the Jamsocket dashboard (opens in a new tab). You'll also need to provide your account and service name in the connect endpoint.

A connect request should look like this:

curl \
  -X POST \
  -H "Authorization: Bearer YOUR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d "{}" \
  https://api.jamsocket.com/v2/service/ACCOUNT_NAME/my-hello-world/connect

Just like in development, making a request to the connection url should return a the hello world string from the backend.

curl CONNECTION_URL_FROM_SPAWN_REQUEST

See your session backend's logs

Finally, you can view logs from your session backends in Production with the Jamsocket CLI.

npx jamsocket logs BACKEND_NAME

Or view logs from your dashboard (opens in a new tab) when you click on the backend name in the Service page.