ca-apm-probe/lib/probes/koa-route.js

CA APM Node.js Agent monitors real-time health and performance of Node.js applications

/**
 * Copyright (c) 2015 CA. All rights reserved.
 *
 * This software and all information contained therein is confidential and proprietary and
 * shall not be duplicated, used, disclosed or disseminated in any way except as authorized
 * by the applicable license agreement, without the express written permission of CA. All
 * authorized reproductions must be marked with this language.
 *
 * EXCEPT AS SET FORTH IN THE APPLICABLE LICENSE AGREEMENT, TO THE EXTENT
 * PERMITTED BY APPLICABLE LAW, CA PROVIDES THIS SOFTWARE WITHOUT WARRANTY
 * OF ANY KIND, INCLUDING WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OF
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL CA BE
 * LIABLE TO THE END USER OR ANY THIRD PARTY FOR ANY LOSS OR DAMAGE, DIRECT OR
 * INDIRECT, FROM THE USE OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, LOST
 * PROFITS, BUSINESS INTERRUPTION, GOODWILL, OR LOST DATA, EVEN IF CA IS
 * EXPRESSLY ADVISED OF SUCH LOSS OR DAMAGE.
 */

var path = require('path');
var agent = require('ca-apm-probe/lib/agent');
var proxy = require('ca-apm-probe/lib/proxy');

var util = require('util');
var methods = require('methods');
var logger = require("ca-apm-probe/lib/logger");


var targetModule = new Object;

module.exports = function (KoaRoute) {

    targetModule.router = KoaRoute;
    targetModule.methodMap = getMethodsWithProbes();

    // instrument each route defined by application

    methods.forEach(function wrap(method) {

        proxy.before(KoaRoute, method, instrumentRoutes)
    });

};

// instrument a given route by registering a call back
function instrumentRoutes(obj, args, storage) {
    proxy.callback(args, 1, routeHook, null);

}

// route hook call back for each registered route request
function routeHook(obj, args, storage) {

    logger.debug('koa-route hook');

    var res = args[0].res;
    var req = args[0].req;
    var eventNameFormatted = 'koa.route';
    var ctx = storage.get('ctx') || req.__CA_ctx;


    if (logger.isDebug()) {
        if (ctx) {
            logger.debug('%s[%d %d %d]: path - %s', eventNameFormatted, ctx.txid, ctx.lane, ctx.evtid, req.url);
        }
        else {
            logger.debug('%s - no context', eventNameFormatted);
            logger.debug((new Error('No context')).stack);
        }
    }

    ctx = agent.asynchEventStart(ctx, eventNameFormatted, {
        route: args[0].routePath,
        http_method: req.method
    });

    storage.set('ctx', ctx);

    var errorObject = new Object();

    var end_save = res.end;

    res.end = function () {
        if (res.finished === false && ctx) {
            ctx = agent.asynchEventDone(ctx, eventNameFormatted, null,
                errorObject);

            if (ctx) {
                agent.asynchEventFinish(ctx);
            }
        }

        end_save.apply(res, arguments);
    };
}


function getMethodsWithProbes() {
    if (!targetModule.methodMap) {
        var mt = new Object;
        mt[0] = 'koa#route';
        targetModule.methodMap = mt;
    }
    return targetModule.methodMap;
}

function instrument(methodMap) {
    targetModule.methodMap = methodMap;
}

module.exports.getMethodsWithProbes = getMethodsWithProbes;

module.exports.instrument = instrument.bind(module);