Function startWSManagementClient

lib/management/push.js:87–271

* Starts background task that updates configuration and pushes stats. * * Receives pushed Websocket messages on configuration updates, and * sends stat messages in response to API sollicitations. * * @param {string} url API endpoint * @param {string} token API authentication token * @param {f

(url, token, cb)

 * @returns {undefined}
 */
function startWSManagementClient(url, token, cb) {
    logger.info('connecting to push server', { url });
    function _logError(error, errorMessage, method) {
        if (error) {
            logger.error(`management client error: ${errorMessage}`,
              { error: reshapeExceptionError(error), method });
        }
    }

    const socketsByChannelId = [];
    const headers = {
        'x-instance-authentication-token': token,
    };
    const agent = createWSAgent(url, process.env, logger);

    const ws = new WebSocket(url, subprotocols, { headers, agent });
    let pingTimeout = null;

    function sendPing() {
        if (ws.readyState === ws.OPEN) {
            ws.ping(err => _logError(err, 'failed to send a ping', 'sendPing'));
        }
        pingTimeout = setTimeout(() => ws.terminate(), PING_INTERVAL_MS);
    }

    function initiatePing() {
        clearTimeout(pingTimeout);
        setTimeout(sendPing, PING_INTERVAL_MS);
    }

    function pushStats(options) {
        if (process.env.PUSH_STATS === 'false') {
            return;
        }
        const fromURL = `http://${cloudServerHost}:${cloudServerPort}/_/report`;
        const fromOptions = {
            json: true,
            headers: {
                'x-scal-report-token': process.env.REPORT_TOKEN,
                'x-scal-report-skip-cache': Boolean(options && options.noCache),
            },
        };
        request.get(fromURL, fromOptions, (err, response, body) => {
            if (err) {
                _logError(err, 'failed to get metrics report', 'pushStats');
                return;
            }
            ws.send(ChannelMessageV0.encodeMetricsReportMessage(body),
                err => _logError(err, 'failed to send metrics report message',
                    'pushStats'));
        });
    }

    function closeChannel(channelId) {
        const socket = socketsByChannelId[channelId];
        if (socket) {
            socket.destroy();
            delete socketsByChannelId[channelId];