mac-/hapi-statsd

var StatsdClient = require('statsd-client'),
    Hoek = require('@hapi/hoek'),
    defaults = {
        statsdClient: null,
        host: 'localhost',
        port: '8125',
        prefix: 'hapi',
        pathSeparator: '_',
        template: '{path}.{method}.{statusCode}',
        defaultFilter: {
            enableCounter: true,
            enableTimer: true,
        },
        filters: [],
    };

var register = function (server, options) {
    var settings = Hoek.applyToDefaults(defaults, options || {}),
        statsdClient = options.statsdClient || new StatsdClient({
            host: settings.host,
            port: settings.port,
            prefix: settings.prefix
        }),
        normalizePath = function(path) {
            path = (path.indexOf('/') === 0) ? path.substr(1) : path;
            return path.replace(/\//g, settings.pathSeparator);
        },
        filterCache = {}, //cache results so that we don't have to compute them every time
        getFilter = function(statName, route, status) {
            var cachedFilter = filterCache[statName];
            if(cachedFilter) {
                return cachedFilter;
            }

            var foundFilter = settings.filters.find(function(filter) {
                if (filter.id && route.settings && route.settings.id !== filter.id) {
                    return false;
                }

                if (filter.path && route.path !== filter.path) {
                    return false;
                }

                if (filter.status && status !== filter.status) {
                    return false;
                }

                if (filter.method && route.method.toUpperCase() !== filter.method.toUpperCase()) {
                    return false;
                }

                // If none of the above checks failed, then we have a match
                return true;
            });

            return filterCache[statName] = Hoek.applyToDefaults(settings.defaultFilter, foundFilter || {});
        };

    server.decorate('server', 'statsd', statsdClient);

    server.ext('onPreResponse', function (request, h) {
        var startDate = new Date(request.info.received);
        var statusCode = (request.response.isBoom) ? request.response.output.statusCode : request.response.statusCode;

        var path = request._route.path;
        var specials = request._core.router.specials;

        if (request._route === specials.notFound.route) {
            path = '/{notFound*}';
        }
        else if (specials.options && request._route === specials.options.route) {
            path = '/{cors*}';
        }
        else if (request._route.path === '/' && request._route.method === 'options') {
            path = '/{cors*}';
        }

        var statName = settings.template
            .replace('{path}', normalizePath(path))
            .replace('{method}', request.method.toUpperCase())
            .replace('{statusCode}', statusCode);

        statName = (statName.indexOf('.') === 0) ? statName.substr(1) : statName;

        var filter = getFilter(statName, request._route, statusCode);
        if (filter.name) {
            statName = filter.name;
        }

        if (filter.enableCounter) {
            statsdClient.increment(statName);
        }

        if (filter.enableTimer) {
            statsdClient.timing(statName, startDate);
        }

        return h.continue;
    });

};

var pkg = require('../package.json');
var name = pkg['name'];
var version = pkg['version'];

exports.plugin = {
  register: register,
  name: name,
  version: version,
  pkg: pkg
};