aws-xray-sdk-core/dist/lib/segments/plugins/plugin.js

AWS X-Ray SDK for Javascript

"use strict";
var http = require('http');
var Plugin = {
    METADATA_TIMEOUT: 1000,
    /**
     * Asynchronously retrieves metadata from on-instance endpoint with an HTTP request using retries for
     * requests that time out.
     * @param {object} options - The HTTP options to make the request with
     * @param {function} callback - callback to plugin
     */
    getPluginMetadata: function (options, callback) {
        const METADATA_RETRY_TIMEOUT = 250; // Millis
        const METADATA_RETRIES = 5;
        var retries = METADATA_RETRIES;
        var getMetadata = function () {
            var httpReq = http.__request ? http.__request : http.request;
            var req = httpReq(options, function (res) {
                var body = '';
                res.on('data', function (chunk) {
                    body += chunk;
                });
                res.on('end', function () {
                    if (this.statusCode === 200 || this.statusCode === 300) {
                        try {
                            body = JSON.parse(body);
                        }
                        catch (e) {
                            callback(e);
                            return;
                        }
                        callback(null, body);
                    }
                    else if (retries > 0 && Math.floor(this.statusCode / 100) === 5) {
                        retries--;
                        setTimeout(getMetadata, METADATA_RETRY_TIMEOUT);
                    }
                    else {
                        callback(new Error(`Failed to retrieve metadata with options: ${options}`));
                    }
                });
            });
            req.on('error', function (err) {
                callback(err);
            });
            req.on('timeout', function () {
                req.abort();
            });
            req.setTimeout(Plugin.METADATA_TIMEOUT);
            req.end();
        };
        getMetadata();
    }
};
module.exports = Plugin;