extend-event-handler-python

flowchart LR
   subgraph AccelByte Gaming Services
   KF[Kafka]
   KB[Kafka Connect]  
   subgraph Extend Event Handler App

   SV["gRPC Server\n(you are here)"]   
   end   
   KB --- SV
   KF --- KB
   end   

AccelByte Gaming Services (AGS) capabilities can be extended with Extend Event Handler apps. An Extend Event Handler app is a gRPC server which listens to Kafka events from AGS via Kafka Connect and takes actions according to a custom logic.

Overview

This repository serves as a template project for an Extend Event Handler app written in Python. You can clone this repository and start creating custom event handler by including the relevant AGS event specification and implementing your own logic to handle AGS Kafka events.

By using this repository as a template project, you will get some instrumentation for observability out-of-the-box so that metrics, traces, and logs will be available when the app is deployed. Since the source code is included, you can customize them according to your needs.

As an example to get you started, this template project contains a sample event handler which will listen to userLoggedIn event from AGS and then proceed to grant an entitlement to the said user.

Project Structure

...
├── src
│  ├── accelbyte_grpc_plugin
│  │  ├── __init__.py
│  │  ├── interceptors
│  │  │  ├── __init__.py
│  │  │  ├── logging.py
│  │  │  └── metrics.py
│  │  └── opts
│  │    ├── __init__.py
│  │    ├── grpc_health_checking.py
│  │    ├── grpc_reflection.py
│  │    ├── loki.py
│  │    ├── prometheus.py
│  │    └── zipkin.py
│  └── app
│    ...
│    └── services
│      ├── __init__.py
│      └── login_handler.py   # Where we put custom logic that will get called when the event 
│                             # we interested got invoked
...

The AGS event specification can be obtained here. For the sample event handler, we are only interested in userLoggedIn event. Therefore, we only include the AGS event specification for IAM.

Prerequisites

Before starting, you will need the following.

1. Windows 11 WSL2 or Linux Ubuntu 22.04 with the following installed.

   a. Bash

   bash --version
   
   GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu)
   ...
   

   b. Make

   • To install from Ubuntu repository, run: sudo apt update && sudo apt install make

   make --version
   
   GNU Make 4.3
   ...
   

   c. Docker (Docker Engine v23.0+)

   • To install from Ubuntu repository, run: sudo apt update && sudo apt install docker.io
   • Add your user to docker group: sudo usermod -aG docker $USER
   • Log out and log back in so that the changes take effect

   docker version
   
   ...
   Server: Docker Desktop
    Engine:
     Version:          24.0.5
   ...
   

   d. Python 3.10

   • To install from Ubuntu repository, run: sudo apt update && sudo apt install python3 python3-venv

   python3 --version
   
   Python 3.10.12
   

   e. grpcui

   • Use binary available here

   grpcui --version
   
   grpcui v1.4.1
   

2. Access to AccelByte Gaming Services demo environment.

   a. Base URL:

   • For Starter tier e.g. https://spaceshooter.prod.gamingservices.accelbyte.io
   • For Premium tier e.g. https://dev.accelbyte.io

   b. Create a Game Namespace if you don't have one yet. Keep the Namespace ID.

   c. Create an OAuth Client with confidential client type with the following permissions. Keep the Client ID and Client Secret.

   • For AGS Premium customers:
     • ADMIN:NAMESPACE:{namespace}:USER:*:FULFILLMENT [CREATE]
   • For AGS Starter customers:
     • Platform Store -> Fulfillment (Create)

3. A published AGS Store. Take a note of the item id which is to be granted after a user in a certain namespace successfully logged in.

Setup

To be able to run the sample event handler, you will need to follow these setup steps.

1. Create a docker compose .env file by copying the content of .env.template file.

   ⚠️ The host OS environment variables have higher precedence compared to .env file variables: If the variables in .env file do not seem to take effect properly, check if there are host OS environment variables with the same name. See documentation about docker compose environment variables precedence for more details.

2. Fill in the required environment variables in .env file as shown below.

   AB_BASE_URL=https://demo.accelbyte.io     # Base URL of AccelByte Gaming Services demo environment
   AB_CLIENT_ID='xxxxxxxxxx'                 # Client ID from the Prerequisites section
   AB_CLIENT_SECRET='xxxxxxxxxx'             # Client Secret from the Prerequisites section
   AB_NAMESPACE='xxxxxxxxxx'                 # Namespace ID from the Prerequisites section
   ITEM_ID_TO_GRANT='xxxxxxxxxx'             # Item id from a published store we noted previously
   

Building

To build this sample app, use the following command.

make build

Running

To (build and) run this sample app in a container, use the following command.

docker compose up --build

Testing

Test in Local Development Environment

The sample event handler can be tested locally using grpcui.

1. Run this Extend Event Handler sample app by using the command below.

   docker compose up --build

2. Run grpcui with the following command.

   grpcui -plaintext localhost:6565

   ⚠️ If you are running grpc-plugin-dependencies stack alongside this sample app as mentioned in Test Observability: Use localhost:10000 instead of localhost:6565. This way, the gRPC server will be called via Envoy service within grpc-plugin-dependencies stack instead of directly.

3. Now in grpcui, send a sample of kafka event you are interested in. In this case, we are interested in userLoggedIn event. So, we are using sample payload here.

   {
     "payload": {
        "userAccount": {
           "userId": "string",
           "emailAddress": "string",
           "country": "string",
           "namespace": "string"
        },
        "userAuthentication": {
           "platformId": "string",
           "refresh": true
        }
     },
     "id": "string",
     "version": 0,
     "name": "string",
     "namespace": "string",
     "parentNamespace": "string",
     "timestamp": "2019-08-24T14:15:22Z",
     "clientId": "string",
     "userId": "string",
     "traceId": "string",
     "sessionId": "string"
   }

   ❗ You can change the field value you are interested in to suits your need, e.g. namespace , userId, etc

   Finally, make sure to select the right service name and method name and click Invoke to send the request.

   

   ❗ If you are interested on other events: you can find it here.

4. If successful, you will see in the response as follows and you can also see the item granted to the user you are using for this test.

   

   

Test Observability

To be able to see the how the observability works in this sample app locally, there are few things that need be setup before performing tests.

1. Uncomment loki logging driver in docker-compose.yaml

    # logging:
    #   driver: loki
    #   options:
    #     loki-url: http://host.docker.internal:3100/loki/api/v1/push
    #     mode: non-blocking
    #     max-buffer-size: 4m
    #     loki-retries: "3"
   

   ⚠️ Make sure to install docker loki plugin beforehand: Otherwise, this sample app will not be able to run. This is required so that container logs can flow to the loki service within grpc-plugin-dependencies stack. Use this command to install docker loki plugin: docker plugin install grafana/loki-docker-driver:latest --alias loki --grant-all-permissions.

2. Clone and run grpc-plugin-dependencies stack alongside this sample app. After this, Grafana will be accessible at http://localhost:3000.

   git clone https://github.com/AccelByte/grpc-plugin-dependencies.git
   cd grpc-plugin-dependencies
   docker compose up
   

   ❗ More information about grpc-plugin-dependencies is available here.

3. Perform testing. For example, by following Test in Local Development Environment.

Deploying

To deploy this app to AGS, follow the steps below.

1. Create a new Extend Event Handler app on Admin Portal. Keep the Repository URI.

2. Download and setup extend-helper-cli (only if it has not been done previously).

3. Perform docker login with extend-helper-cli using the following command.

   extend-helper-cli dockerlogin --namespace <my-game> --app <my-app> --login
   

   ❗ For your convenience, the above extend-helper-cli command can also be copied from Repository Authentication Command under the corresponding app detail page.

4. Build and push sample app docker image to AccelByte ECR using the following command.

   make imagex_push IMAGE_TAG=v0.0.1 REPO_URL=xxxxxxxxxx.dkr.ecr.us-west-2.amazonaws.com/accelbyte/justice/development/extend/xxxxxxxxxx/xxxxxxxxxx
   

   ❗ The REPO_URL is obtained from step 1: It can be found under 'Repository URI' in the app detail.

5. Open Admin Portal, go to Extend -> Event Handler. And then select the extend app.

6. To deploy selected image tag, click Image Version History and select desired image tag to be deployed.

7. Click Deploy Image, confirm the deployment and go back to App Detail by clicking Cancel.

8. Wait until app status is running.

For more information on how to deploy an Extend Event Handler app, see here.

Next Step

Proceed to modify this template project and create your custom event handler. See here for more details.