bron10/the-syncing-stores

Syncing-stores

This repository contains solution how can we sync two Data-stores. The solution is based on events. where each store has a listener that listen to the changes and sync up the updates to one another. Two data stores implemented are :

1. MongoDB
2. Redis

The problem took around 5 hours for first prototype completion. The best part of this application is minimal latency.

Improvements can be more unit tests cases.

How to setup.

• Setup local Redis and MongoDB. Refer config/default.json for default setup configuration.

• The Redis server by default on local is pretty much auto-started.

• Run following command to start mongoDB on local sudo mongod --replSet rs0

• dont forget to create data store location /data/db

• We need replicaSet functionality activated in mongoDB to use listening feature of mongoDB. Ref[https://docs.mongodb.com/v3.6/changeStreams/]

• Start the mongo shell in terminal by command mongo. initiate the replica set to default db as shown below rs.initiate()

• Once both data stores are done. Run the following commands

  1. Created migration using npx migrate create customers

  2. npm install //Install packages

  3. npm start //for prod run

  4. Use any client such as postman as shown in demo Runs at http://localhost:3000/

APIS

1. Create customer

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POST: /v1/customer Content-Type : application/json body: { "name": "cc Inc", "address": "cahce 37", }

The above api inserts data in DS store 1. whereas if same api used with /v2 inserts data to DS store 2. The same logic goes for PUT, GET. The other APIS are also shown below with different versions

2. Update customer

---

PUT: /v2/customer/:uid Content-Type : application/json body: { "name": "cc Inc", "address": "cahce 37", }

Here uid is unique id that is created when we insert customer/user data in above CREATE api.

3. Get all customer

---

GET: /v1/customers

Get list of all customers.

DEMO

1. Create a new customer with v1 (DS : mongoDB)

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2. Update an existing customer with v2 (DS : redis)

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3. Create a new customer with v2 (DS : redis)

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4. Update an existing customer with v1 (DS : mongoDB)