Multiple Apps Parse Server

Changelog

• collectionPrefix for mongodb can be optional (2017/10/31).
• be able to enable/disable single parse server app(2017/10/31).
• add app and customer field, so that customer can handle multiple apps(2017/10/30).

Objective

• run and manage multiple parse apps (instances) in a server and using a single port.
• one code, one database, create a parse app in one second.
• parse dashboard integrated, each app's manager can log into parse dashboard to manage their app.
• one admin account in parse dashboard to manage all apps
• customers(clients) can manage their own apps (2017/10/30)

Prerequisites

• Node.JS 7.6 or above
• MongoDB (if run in local)
• pm2

Architecture

• Parse Server
• Parse Server Dashboard
• each parse app has different port and use node-http-proxy to handle port route.

Install

• add config.json (can copy from config_sample.json)

{
  "portFrom":1337, //the port of the first app will be started from 1337 
  "maxInstances":100, //maxiumum number of parse apps (<100 is suggested)  

  "parseDashboardURI":"https://app.xxx.com:4040", //parse server dashboard public uri
  "globalURI":"https://app.xxx.com",   //parse server public uri
  "databaseURI":"mongodb://localhost:27017/",  //parse server mongodb uri
  "cloudCodeFolder":"./cloudcode/", //parse server cloud code folder, the main.js will be auto created in the sub-folder(named by customer)
  "internalProxyPort":3000, 
  "S3FilesAdapter":{ //parse server s3 file adapter
    "bucket":"xxxx",
    "accessKey":"xxx",
    "secretKey":"xxxx"
  },
  "parseDashboard":{  //parse server dashboard settings
    "port":4040
  }
}

• install node modules and pm2

 npm install

 sudo npm install pm2 -g  

• create the first parse app

  
  app=firstapp customer=c1 node newInstance.js

customer field (optional) , each customer can have multiple apps and can manage these apps with 
the same username and password in parse dashboard.   

newInstance will auto start several processes by using pm2.
 If successfully, you will see

This is firstly start parse dashboard, admin is created.

dashboard URL: https://app.xxx.com:4040 username: admin password: ***

No.1 parse server instance is created! The app and customer information are shown as following, you can copy & paste to your customer

api URL: https://app.xxx.com/firstapp application id: rEIIPpggXbKJCy master key: ZepMVqJMRGuuXd //please keep master key in secret dashboard URL: https://app.xxx.com:4040 dashboard username:c1 dashboard password: ** //please keep this password in secret

 if you want to test locally, try `http://localhost:3000/firstapp` for the first app parse server and
 `http://localhost:4040` for parse dashboard.

 you can create the second app by `app=secondapp customer=c1 node newInstance.js`, and so on.

* cloud code monitoring

we use pm2 watch method to monitor the change of cloud code folder, therefore,
 once the main.js or other files in the folder are modified, the corresponding parse app will be restart.
Each app developer can deploy their cloud code by using git server(not include here).
* set load balance or dns server to your own domain, then enjoy!

## Enable/Disable One of Parse Server Apps
 you can enable/disable one of parse server apps by using the following command

app=AppName enable=true/false node setapp

## MongoDB CollectionPrefix
parse server supports collection prefix for mongodb, so that you can use one database link for multiple parse server apps.
if you want to turn off collection prefix, set "useCollectionPrefix":false in config.json.

## PM2 Script File
* initial.json - route-proxy and parse-dashboard
* appServers.json - all parse apps

There are two processes in inital.json, one is route-proxy, the other is parse-dashboard,
to start/stop these two processes, 

pm2 start/stop initial.json

appServers.json contains all parse apps processes, To start/stop all parse apps, 

pm2 start/stop appServers.json

## Performance 
### pm2 status at a glance

┌─────────────────┬────┬──────┬───────┬────────┬─────────┬────────┬─────┬───────────┬─────────┬──────────┐ │ App name │ id │ mode │ pid │ status │ restart │ uptime │ cpu │ mem │ user │ watching │ ├─────────────────┼────┼──────┼───────┼────────┼─────────┼────────┼─────┼───────────┼─────────┼──────────┤ │ firstapp │ 0 │ fork │ 65458 │ online │ 0 │ 52s │ 0% │ 73.9 MB │ richard │ enabled │ │ parse-dashboard │ 2 │ fork │ 65564 │ online │ 2 │ 37s │ 0% │ 53.4 MB │ richard │ disabled │ │ parse-route │ 1 │ fork │ 65561 │ online │ 2 │ 37s │ 0% │ 40.6 MB │ richard │ disabled │ │ secondapp │ 3 │ fork │ 65485 │ online │ 0 │ 44s │ 0% │ 74.9 MB │ richard │ enabled │ │ thirdapp │ 4 │ fork │ 65533 │ online │ 0 │ 38s │ 3% │ 76.5 MB │ richard │ enabled │ └─────────────────┴────┴──────┴───────┴────────┴─────────┴────────┴─────┴───────────┴─────────┴──────────┘

each app occupies around 70MB memory size when no traffic. The 4-GB ram size server can handle at least 40 low-traffic 
parse apps.

## Clean environment
if you are in development stage, and need to have a clean environment. 
previous generated apps are not needed anymore. you can do 
```sh
 ./cleanenv.sh

all the process will be deleted and all the parse apps are also delete. (the data in mongodb still be remained)