Casava Common Library

This is the common shared library used across all the Node.js microservice within Casava. Common feature/code are placed in this library.

Usage

Using the library requires AWS IAM credentials loaded as enviromental variables with the following keys value pairs:

AWS_ACCESS_KEY_ID=xxxxxxxxxxxxxxxx
AWS_SECRET_ACCESS_KEY=xxxxxxxxxxxxxxx

# For publishing to SNS topics
AWS_SNS_TOPIC_ARN=xxxxxxxxxxxxxxxxxx

Initializing the library

The library exposes a single entrypoint (a singleton) for accessing services provided. so as to avoid re-validation of AWS credentials per initialization.

import { config } from "dotenv";
import casavaLibrary from "casava-common"

const libraryInstance1 = casavaLibrary(); // returns an instance of CasavaCommonLibrary
const libraryInstance2 = casavaLibrary();

libraryInstance1 == libraryInstance2 // returns true: it's a singleton.

Services:

all services provided are public properties of CasavaCommonLibrary class.

CasavaCommonLibrary.pubSub : PubSub

• CasavaCommonLibrary.pubSub.publish: publishing to an AWS SNS Topic

  const library = casavaLibrary();
  const params = {
    message: 'Hello world',
    filters: [
      {
        attributeName: 'useraction', // attribute name for message filtering
        attributeValues: ['registration', 'request_verification'] // values of the attribute name:  must be of type string[]
      }
    ],
    topicArn: AWS_TOPIC_ARN // if not provided, it uses the AWS_SNS_TOPIC_ARN .env variable 
  }
  
  const publishJob = library.pubSub.publish(params);
  
  publishJob.then((res: PublishedMessageResponse) => console.log(res)).catch(console.error); // async/await can also be used.