ca-apm-probe/lib/utils/trace-util.js

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

/**
 * Copyright (c) 2016 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.
 */

'use strict';

// truncate parameter value string to this limit
var MAX_ARG_VALUE_LENGTH = 100;

// value expected to be string
function truncateEventArgValue(value) {
    var strValue = value;

    //truncation logic
    if (strValue && strValue.length > MAX_ARG_VALUE_LENGTH) {
        strValue = strValue.substr(0, MAX_ARG_VALUE_LENGTH) + ' ...(truncated)';
    }

    return strValue;
}

// always returns a string value
function formatEventArgValueObject(object) {
    if (object) {
        return truncateEventArgValue((JSON.stringify(object)));
    }

    return '';
}

function createErrorObject(errorClass, errMsg) {
    var errorObject = {
        class: errorClass,
        msg: formatEventArgValueObject(errMsg)
    }

    return errorObject;
}

function getFormattedErrorObject(err) {
    return (err instanceof Error) ? {
        class: err.name,
        msg: truncateEventArgValue(err.message)
    } : null;
}

function checkCallbackArgsForError(args, defaultErrorClass) {

    // based on callback calling conventions, first argument to callback is error
    var err = args[0];

    if (err != null) {
        var object = getFormattedErrorObject(err);

        if (!object && defaultErrorClass) {
            object = createErrorObject(defaultErrorClass, err);
        }

        return object;
    }

    return null;
}


module.exports.truncateEventArgValue = truncateEventArgValue;
module.exports.formatEventArgValueObject = formatEventArgValueObject;
module.exports.createErrorObject = createErrorObject;
module.exports.getFormattedErrorObject = getFormattedErrorObject;
module.exports.checkCallbackArgsForError = checkCallbackArgsForError;