mof-bottleneck/index.js

A middleware wrapped Bottleneckp module for floodesh

'use strict'

const Bottleneck = require('bottleneckp')

module.exports = (options) => {
    return function* ( ctx, next ) {
	if(!ctx.app.scheduler){
	    let scheduler = ctx.app.scheduler = Object.create(null);
	    Object.keys(options).forEach(cfg => scheduler[cfg] = new Bottleneck.Cluster(options[cfg].concurrent, options[cfg].rate,options[cfg].priorityRange,options[cfg].defaultPriority, options[cfg].homogenous) );
	}
	
	yield new Promise((resolve) => {
	    let clusterCfg = ctx.func;
	    if( !(clusterCfg in ctx.app.scheduler) )
		clusterCfg = "defaultCfg";

	    ctx.opt.clusterCfg = clusterCfg;
	    let cluster = ctx.app.scheduler[clusterCfg];
	    
	    if( ! ctx.opt.hasOwnProperty("limiter") )
		ctx.opt.limiter = "default";

	    ctx.app.logger.verbose("Bottleneck submit, cluster: %s, limiter: %s", clusterCfg,ctx.opt.limiter);
	    ctx.app.logger.verbose("Bottleneck cluster: %s, status: %s", clusterCfg, cluster.status);
	    
	    if(ctx.scounter) ctx.scounter('bottleneck');// for metrics collecting
	    
	    cluster.key(ctx.opt.limiter).submit( ctx.opt.priority||1 ,done => {
	    	ctx.app.logger.verbose("Bottleneck callback, cluster: %s, limiter: %s",ctx.opt.clusterCfg, ctx.opt.limiter);
    	    	ctx.resourceList.bottleneck = done;
	    	resolve();
    	    });
	});
	
	yield next();
	ctx.resourceList.bottleneck();// release bottleneck resource here
	delete ctx.resourceList.bottleneck;
	ctx.app.logger.verbose("Bottleneck released, cluster: %s, limiter: %s",ctx.opt.clusterCfg, ctx.opt.limiter);
    }
}