To the discussion in the [[http://trac.prcn.bitcoin-analytics.com/ceasy/ticket/515]] 

We discussed list of modules affected.
* collector/bin/collector.js - entry point for collector process
* server/lib/config.js - constants {{{enabledCurrencies}}}, {{{streamAPIModes}}} the latter intended to be used in {{{exchangeAPIObj.init}}} method
* server/lib/depthAPI.js - all actual configuration of exchange objects defined here. Every exchange is represented by its exchange object instance. Module is responsible for creating instances and provides central storage for them in the form of collection(hash object). Orderbooks accessed from collector structures through public method {{{getCurrentBook2}}} passing exchange tickers of type string as a parameter. Trades on the other hand broadcasted through central event emitter object defined in {{{events}}} module. Trades messages source is every exchange instance. Collector structures register listeners for trades messages. 


Collector side:
* collector/bin/collector.js method {{{nextTick}}}
{{{ 
process.nextTick(function ()
{ 
...
var     exchangeApi = require('../../server/lib/depthAPI')

exchangeApi.init(config.tickersToFetch, config.streamAPIModes, config.enabledCurrencies)
...
}
}}}
* server/lib/config.js constants {{{enabledCurrencies}}}, {{{streamAPIModes}}} the latter intended to be used in {{{exchangeAPIObj.init}}} method to select specific version of internal adapter implementation (REST or Websocket real time synchronized)
{{{
exports.enabledCurrencies = ['USD', 'EUR', 'CNY',

exports.streamAPIModes = {..., coinbaseUSD: 'coinbase1'}
}}}
* server/lib/depthAPI.js
each exchange represented by instance of exchangeAPIObj, collector requests each order book using method {{{getCurrentBook2}}}
while published {{{events}}} is global event emitter instance to pass trades events.
{{{
...

exports.events = new (require('events').EventEmitter)() //trade events, orderbook events

var exchangeAPIObjs = {}

...

exports.getCurrentBook2 = function(ticker)
{
        return exchangeAPIObjs[ticker].currentHashBook
}
...
}}}

method {{{init}}} takes list of exchanges specific for current server to instantiate and initialize exchange objects which is returned as hash(key=ticker,value=exObj) and stored in {{{exchangeAPIObjs}}} in the module scope.
{{{
exports.init = function (tickersToFetch, streamApiModes, currencies)
{
        exchangeAPIObjs = arr.mapToHash(tickersToFetch, function(ticker)
        {
                var exObj = apiParams[ticker].exAPIObj ? new apiParams[ticker].exAPIObj() : new api.exAPIDefault()

                exObj.init(ticker, apiParams, exports.events, streamApiModes)
                return exObj
        })
...
}
}}}

{{{apiParams}}} is initialize from execution of the method {{{makeApiParams}}}
{{{
...

var apiParams = makeApiParams()
exports.apiParams = apiParams
}}}

where definition of the method {{{makeApiParams}}} is as following
{{{
function makeApiParams()
{
        return {
...
,       mtgoxUSD: makeMtgox('USD')
,       btceUSD: {
                url: 'https://btc-e.com/api/3/depth/btc_usd?limit=2000',
                cur : 'USD',
                parse :  fixPriceKeysEx(
                        function (x){ return x['btc_usd']},
                        'bids', 'asks',
                        fn.id),
                exAPIObj: api.btcePollingTrades,
                trades_url: 'https://btc-e.com/api/3/trades/btc_usd?limit=2000',
                trades_key: 'btc_usd',
                polling_freq: 3600 / 30,
                pollingAliveTimeout: 5 * 60 * 1000,
    DoRejectUnauthorized : true
        }
...

}}}

where {{{coinbaseUSD}}} is defined as 
{{{
...

, coinbaseUSD: {
        cur: 'USD',
        exAPIObj: require('./exchange-api/coinbaseAPIClass').exAPICoinbase
}
...
}}}

where {{{api.exAPICoinbase}}} is included from 
{{{
...
, api = require('./exchange-api/apiClasses')
...
}}}