Event Manager Backend (event-manager-backend)

Welcome to Event Manager Backend (event-manager-backend)

Table of contents

• Introduction
• Requirements
• Installation
• Configuration
• Troubleshooting & FAQ

Introduction

The service is based on Strapi JS framework.

Requirements

• CPU cores >= 1
• RAM >= 256MB
• Git 2.*
• Docker 20.*

Installation

• Set up git to have ssh access to the repository
• Clone the source into local machine

$ git clone git@github.com:dasmeta/event-manager-backend.git

• Go to the project source $ cd event-manager-backend
• Run make with prefered configuration to start development environment.
• Run docker build to create a production ready image and install project dependencies.

$ docker build -t event-manager-backend:latest .

Configuration

• Create an environment file .env and defined variables

# Web Server
HOST=0.0.0.0
PORT=1337
SERVE_ADMIN_PANEL=

# Database

# mongo
DATABASE_CLIENT=mongo
DATABASE_URL=mongodb://strapi:strapi@mongo/strapi?authSource=admin
// or
DATABASE_HOST=strapi
DATABASE_USERNAME=strapi
DATABASE_PASSWORD=strapi
DATABASE_NAME=strapi
AUTHENTICATION_DATABASE=admin

# postgres
DATABASE_CLIENT=postgres
DATABASE_HOST=postgres
DATABASE_USERNAME=strapi
DATABASE_PASSWORD=strapi
DATABASE_NAME=strapi

# JWT settings to validate token
JWT_SECRET=
JWT_ALGORITHM="HS256"

# Centralized Authentication
AUTHENTICATION_SERVICE_API_HOST=
AUTHENTICATION_IS_LIVE_MODE=

# For aws lambda with sns trigger
MQ_CLIENT_NAME=SNS
AWS_REGION=
AWS_ACCESS_KEY_ID=
AWS_SECRET_ACCESS_KEY=

• Create and start a container ready to handle connections

$ make up-with-mongo 
$ make up-with-postgres

• The service will be accessible on http://0.0.0.0:8037

If data retention following env variables should be defined

ENABLE_CRON=true
DATA_RETENTION_DAYS=40 // event that are created more than 40 days ago will be remove, but only those which have 100% success
DATA_CLEANUP_HOUR=04 // time in a day on which cleanup job will be executed, in UTC and 24 hour format 

Indexes (MUST!!!)

For smooth performance set following indexes (written in mongo syntax, if using SQL databases must be changed accordingly)

## event (collection / table)

{ entity: 1, entityId: 1 }
{ entity: 1, entityId: 1, createdAt: 1 },
{ topic: 1 }

## event_subscription (collection / table)

{ createdAt: -1 }
{ eventId: 1 }
{ eventId: 1, createdAt: 1 }
{ eventId: 1, subscription: 1 }
{ isError: 1 }
{ isError: 1, isPreconditionFail: 1, isSuccess: 1, updatedAt: 1 }
{ isPreconditionFail: 1 }
{ isSuccess: 1 }
{ subscription: 1 }
{ topic: 1 }
{ topic: 1, subscription: 1 }
{ topic: 1, subscription: 1, isError: 1, "error.message": 1, updatedAt: -1 }
{ topic: 1, subscription: 1, isError: 1, isPreconditionFail: 1, isSuccess: 1 }
{ topic: 1, subscription: 1, isError: 1, isPreconditionFail: 1, isSuccess: 1, createdAt: 1 }
{ topic: 1, subscription: 1, isSuccess: 1 }
{ topic: 1, subscription: 1, isError: 1, isPreconditionFail: 1, isSuccess: 1, "error.message": 1, createdAt: 1 }

Troubleshooting & FAQ

• View service logs

$ docker logs -f --since 2m em-backend

• Run tests

$ docker exec em-backend bash -c "yarn test"

pubSub

Extended event publishing PubSub/Kafka package.

yarn add @dasmeta/event-manager-node-api

start local pub/sub

$ gcloud beta emulators pubsub start $ DATASTORE_EMULATOR_HOST=localhost:8432 DATASTORE_PROJECT_ID=YOUR_GCLOUD_PROJECT_ID gcloud beta emulators datastore start

example1.js

const { registerSubscriber, publish } = require("@dasmeta/event-manager-node-api");

async function test1(data) {
    console.log("test1", data);
}

async function test2(data) {
    console.log("test2", data);
}

async function test3(data) {
    console.log("test3", data);
}

registerSubscriber("dev.test", "dev-test_test1", test1);
registerSubscriber("dev.test", "dev-test_test2", test2);
registerSubscriber("dev.test.other", "dev-test_test3", test3);

setInterval(async () => {
    await publish("dev.test", { key: Date.now() });
}, 300);

setInterval(async () => {
    await publish("dev.test.other", { key2: Date.now() });
}, 500);

PUBSUB_EMULATOR_HOST="localhost:8085" PUBSUB_PROJECT_ID="YOUR_GCLOUD_PROJECT_ID" GCLOUD_PROJECT="YOUR_GCLOUD_PROJECT_ID" node example1.js

example2.js

const { publish, subscribeMulti } = require("@dasmeta/event-manager-node-api");


function subscribe1() {
    subscribeMulti("test", ["dev.test", "dev.test.other"], async (topic, data) => {
        console.log('\x1b[31m%s %s\x1b[0m', " 1 ", topic, data);
    });
}

function subscribe2() {
    // resubscribe
    subscribeMulti("test", ["dev.test"], async (topic, data) => {
        console.log('\x1b[32m%s %s\x1b[0m', " 2 ", topic, data);
    });

    subscribeMulti("test3", ["dev.test", "dev.test.other"], async (topic, data) => {
        console.log('\x1b[33m%s %s\x1b[0m', " 3 ", topic, data);
    });
}


setInterval(async () => {
    await publish("dev.test", { key: Date.now() });
}, 200);

setInterval(async () => {
    await publish("dev.test.other", { key2: Date.now() });
}, 300);

subscribe1();

setTimeout(async () => {
    subscribe2();
}, 20 * 1000);

PUBSUB_EMULATOR_HOST="localhost:8085" PUBSUB_PROJECT_ID="YOUR_GCLOUD_PROJECT_ID" GCLOUD_PROJECT="YOUR_GCLOUD_PROJECT_ID" node example2.js

example3.js

import { autoStart as AutoStart, subscribe as on, publish } from "@dasmeta/event-manager-node-api";

@AutoStart
class Example {
    @on("dev.test")
    async test1(data) {
        console.log("test1", data);
    }

    @on("dev.test")
    async test2(data) {
        console.log("test2", data);
    }

    @on("dev.test.other")
    async test3(data) {
        console.log("test3", data);
    }
}

setInterval(async () => {
    await publish("dev.test", { key: Date.now() });
}, 300);

setInterval(async () => {
    await publish("dev.test.other", { key2: Date.now() });
}, 500);

PUBSUB_EMULATOR_HOST="localhost:8085" PUBSUB_PROJECT_ID="YOUR_GCLOUD_PROJECT_ID" GCLOUD_PROJECT="YOUR_GCLOUD_PROJECT_ID" node example3.js

Kafka : run all examples with env variables

MQ_CLIENT_NAME='Kafka' KAFKA_BROKERS='127.0.0.1:29092'

PubSub : run all examples with env variables

PUBSUB_EMULATOR_HOST="localhost:8085" PUBSUB_PROJECT_ID="YOUR_GCLOUD_PROJECT_ID" GCLOUD_PROJECT="YOUR_GCLOUD_PROJECT_ID"