polished-load-balancer
v0.2.0
Published
Simple R Shiny app load balancer
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15
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polished-load-balancer
polished-load-balancer
is a simple load balancer for a single Shiny app.
- it runs several instances of your Shiny app to overcome the single-process limitation of a standard shiny app
- new Shiny app instances are automatically started and stopped as your app experiences more and less traffic
- it is a middleware for a Node.js Express application, so it can be easily extended
Installation
npm install polished-load-balancer
Simple Example
The following example will serve a Shiny app located in the /srv/shiny_app
folder:
# server.js
import express from 'express'
import polishedLoadBalancer from 'polished-load-balancer'
const plb = await polishedLoadBalancer({
appDir: "/srv/shiny_app",
maxSessions: 1
})
const app = express()
app.use(plb)
app.listen(8080)
If you run the above server using node server.js
, your auto scaling Shiny app will be available at http://localhost:8080
.
Options
The load balancer middleware is created by polishedLoadBalancer(options)
. options
is an object with
the following configurable properties:
appDir: string - the path of the folder containing the Shiny app.
maxSessions: integer > 0 - the max number of active sessions per Shiny app instance before starting up a new Shiny app instance. New Shiny app instances are automatically scaled up and down as each running Shiny app reaches this maxSessions number of sessions.
Prior Work
This package was adapted from node-shiny-proxy by Martin Vergier