MOPO

Table of Contents

1. About
2. Installation
3. Configuration
4. Usage
5. Attribution

About

Mopo is a simple cli tool for replicating MongoDB to PostgreSQL in realtime.

Installation

git clone https://github.com/rebellionpay/mopo mopo && cd mopo
npm i
npm run build

Preparation

MongoDB

Mopo uses Replica Set feature in MongoDB. But you don't have to replicate between MongoDB actually. Just follow the steps below.

Start a new mongo instance with no data:

$ mongod --replSet "rs0" --oplogSize 100

Open another terminal, and go to MongoDB Shell:

$ mongo
....
> rs.initiate()

rs.initiate() command prepare the collections that is needed for replication.

PostgreSQL

Launch postgres instance, and create the new database to use.

Configuration

Create a new .mopo.json file like this:

{
    "mongo": {
        "connection": {
            "uri": "<MONGOQUERY>",
            "options": {
                "useNewUrlParser": true,
                "useUnifiedTopology": true,
                "auto_reconnect": true
            }
        },
        "collectionModels": {
            "users": {
                "_id": {
                    "type": "TEXT",
                    "primary": true
                },
                "email": {
                    "type": "TEXT"
                },
                "name": {
                    "type": "TEXT"
                },
                "createdAt": {
                    "type": "TIMESTAMP"
                },
                "updatedAt": {
                    "type": "TIMESTAMP"
                }
            }
        }
    },
    "postgres": {
        "connection": {
            "config": {
                "host": "localhost",
                "database": "exampleDB"
            }
        }
    },
    "sync": [
        {
            "collection": "users",
            "syncAll": true,
            "watchOperations": [
                "INSERT",
                "UPDATE"
            ]
        }
    ]
}

_id field is required for each collection and should be string.

Field names and types

Currently these native types are supported:

• BIGINT
• BOOLEAN
• VARCHAR
• DATE
• TIMESTAMP
• TEXT

Usage

node dist/index.js --start .mopo.json --log-level debug

Usage: index [options]

Options:
  -s, --start <config file>  start sync with config file
  -sa, --sync-all            Sync all data first if schema syncAll enabled
  -bi, --bulk-insert <number>  Number of documents to insert at once (only works if --sync-all enabled). Default 10.
  -l, --log-level <level>    Log level
  -h, --help                 display help for command

Attribution

Icons made by Icongeek26 from www.flaticon.com