hk-audit-producer

Library to facilitate sending messages to AWS SQS.

Requirements

Preconfigured resources

• AWS SQS: fifo source queue.
• Slack: webhook to receive notifications.
• Sendgrid: template and verified email to send email notifications.

Environment variables

# AWS SQS
AWS_SQS_REGION=
AWS_SQS_SOURCE_QUEUE_URL=

# SLACK
AUDIT_SLACK_NOTIFICATION_URL=

# SENDGRID
AUDIT_SENDGRID_API_KEY=
AUDIT_SENDGRID_FAILURE_NOTIFICATION_TEMPLATE_ID=
AUDIT_SENDGRID_FAILURE_NOTIFICATION_VERIFIED_EMAIL=
AUDIT_SENDGRID_FAILURE_NOTIFICATION_FROM_NAME=
AUDIT_SENDGRID_FAILURE_NOTIFICATION_SUBJECT=
AUDIT_SENDGRID_FAILURE_NOTIFICATION_RECIPIENTS=

Available utilities

• SQSAuditMessage: data type of the message to send to SQS.

• messageHandler(): asynchronous function to send the message to SQS.

Installation

Install via yarn

yarn add @houlak/hk-audit-producer

Usage

import { SQSAuditMessage, messageHandler } from '@houlak/hk-audit-producer'

const messageToSend: SQSAuditMessage = {
  auditType: 'PAYMENT_CANCELLED',
  date: new Date(),
  clientName: 'main-project-name',
  tags: ['tag01', 'tag02', 'tag03'],
  text: 'payment cancelled detail',
  metadata: {
    metadata01: {
      subMetadata0102: 'subMetadata0102',
      subMetadata0102: 'subMetadata0102',
    },
    metadata02: {
      subMetadata0201: 'subMetadata0201',
      subMetadata0202: 'subMetadata0202',
    },
  },
}

const groupId = 'a-group'
const fallbackFile = '/absolute/path/to/fallback/file/file_name.txt'

await messageHandler(messageToSend, groupId, fallbackFile)

Clarifications

• SQSAuditMessage

Define the structure of the message.

Fields auditType, date and clientName are required. tags and metadata are optional.

• messageHandler()

In charge of preparing the message and sending it to SQS.

If message is sent: details of sent message will be logged as info log.

If message could not be sent: will be stored in fallback file, details of unsent message will be logged as error log and notifications of failure will be sent by slack and email.

• Semaphore

When main application call messageHandler() for the first time, a semaphore instance is created and its light is defined in yellow.

If the message could be successfully sent to the SQS, semaphore light is changed to green. If it could not be sent, it is changed to red.

It is the key to handling the fallback file.

• Fallback file

Is a .txt file where the messages that cannot be sent to the SQS are stored.

When a message could not be delivered, it is stored in fallback file and semaphore light is changed to red.

When a message is sent to SQS, semaphore light is changed to green and fallback file is read. Trying to send the messages, those that are sent will be deleted from the file and those that are not will be kept.