func (m *Memcached) gatherServer(
	address string,
	unix bool,
	acc plugins.Accumulator,
) error {
	var conn net.Conn
	if unix {
		conn, err := net.DialTimeout("unix", address, defaultTimeout)
		if err != nil {
			return err
		}
		defer conn.Close()
	} else {
		_, _, err := net.SplitHostPort(address)
		if err != nil {
			address = address + ":11211"
		}

		conn, err = net.DialTimeout("tcp", address, defaultTimeout)
		if err != nil {
			return err
		}
		defer conn.Close()
	}

	// Extend connection
	conn.SetDeadline(time.Now().Add(defaultTimeout))

	// Read and write buffer
	rw := bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn))

	// Send command
	if _, err := fmt.Fprint(rw, "stats\r\n"); err != nil {
		return err
	}
	if err := rw.Flush(); err != nil {
		return err
	}

	values, err := parseResponse(rw.Reader)
	if err != nil {
		return err
	}

	// Add server address as a tag
	tags := map[string]string{"server": address}

	// Process values
	for _, key := range sendMetrics {
		if value, ok := values[key]; ok {
			// Mostly it is the number
			if iValue, errParse := strconv.ParseInt(value, 10, 64); errParse != nil {
				acc.Add(key, value, tags)
			} else {
				acc.Add(key, iValue, tags)
			}
		}
	}
	return nil
}

// Process Twemproxy server stats
func (ti *TwemproxyInstance) processStat(
	acc plugins.Accumulator,
	tags map[string]string,
	data map[string]interface{},
) {
	if source, ok := data["source"]; ok {
		if val, ok := source.(string); ok {
			tags["source"] = val
		}
	}

	metrics := []string{"total_connections", "curr_connections", "timestamp"}
	for _, m := range metrics {
		if value, ok := data[m]; ok {
			if val, ok := value.(float64); ok {
				acc.Add(m, val, tags)
			}
		}
	}

	for _, pool := range ti.Pools {
		if poolStat, ok := data[pool]; ok {
			if data, ok := poolStat.(map[string]interface{}); ok {
				poolTags := copyTags(tags)
				poolTags["pool"] = pool
				ti.processPool(acc, poolTags, pool+"_", data)
			}
		}
	}
}

func gatherPoolStats(pool poolInfo, acc plugins.Accumulator) error {
	lines, err := internal.ReadLines(pool.ioFilename)
	if err != nil {
		return err
	}

	if len(lines) != 3 {
		return err
	}

	keys := strings.Fields(lines[1])
	values := strings.Fields(lines[2])

	keyCount := len(keys)

	if keyCount != len(values) {
		return fmt.Errorf("Key and value count don't match Keys:%v Values:%v", keys, values)
	}

	tag := map[string]string{"pool": pool.name}

	for i := 0; i < keyCount; i++ {
		value, err := strconv.ParseInt(values[i], 10, 64)
		if err != nil {
			return err
		}

		acc.Add(keys[i], value, tag)
	}

	return nil
}

func (n *Mesos) gatherUrl(addr *url.URL, acc plugins.Accumulator) error {
	resp, err := client.Get(fmt.Sprintf("%s/metrics/snapshot", addr.String()))
	if err != nil {
		return fmt.Errorf("Unabale to make HTTP request %s: %v", addr.String(), err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("Unexpected HTTP status %s: %v", addr.String(), resp.Status)
	}

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return err
	}

	metrics := map[string]interface{}{}
	if err := json.Unmarshal(body, &metrics); err != nil {
		return err
	}

	tags := getTags(addr)

	for k, v := range metrics {
		name := strings.Replace(k, "/", "_", -1)
		acc.Add(name, v.(float64), tags)
	}

	return nil
}

func (z *Zfs) Gather(acc plugins.Accumulator) error {
	kstatMetrics := z.KstatMetrics
	if len(kstatMetrics) == 0 {
		kstatMetrics = []string{"arcstats", "zfetchstats", "vdev_cache_stats"}
	}

	kstatPath := z.KstatPath
	if len(kstatPath) == 0 {
		kstatPath = "/proc/spl/kstat/zfs"
	}

	tags := getTags(kstatPath)

	for _, metric := range kstatMetrics {
		lines, err := internal.ReadLines(kstatPath + "/" + metric)
		if err != nil {
			return err
		}
		for i, line := range lines {
			if i == 0 || i == 1 {
				continue
			}
			if len(line) < 1 {
				continue
			}
			rawData := strings.Split(line, " ")
			key := metric + "_" + rawData[0]
			rawValue := rawData[len(rawData)-1]
			value, _ := strconv.ParseInt(rawValue, 10, 64)
			acc.Add(key, value, tags)
		}
	}
	return nil
}

// Process pool data in Twemproxy stats
func (ti *TwemproxyInstance) processPool(
	acc plugins.Accumulator,
	tags map[string]string,
	prefix string,
	data map[string]interface{},
) {
	serverTags := make(map[string]map[string]string)

	for key, value := range data {
		switch key {
		case "client_connections", "forward_error", "client_err", "server_ejects", "fragments", "client_eof":
			if val, ok := value.(float64); ok {
				acc.Add(prefix+key, val, tags)
			}
		default:
			if data, ok := value.(map[string]interface{}); ok {
				if _, ok := serverTags[key]; !ok {
					serverTags[key] = copyTags(tags)
					serverTags[key]["server"] = key
				}
				ti.processServer(acc, serverTags[key], prefix, data)
			}
		}
	}
}

func (e *Engine) AddEngineStats(keys []string, acc plugins.Accumulator, tags map[string]string) {
	engine := reflect.ValueOf(e).Elem()
	for _, key := range keys {
		acc.Add(
			key,
			engine.FieldByName(engineStats[key]).Interface(),
			tags,
		)
	}
}

func (k *Kafka) Gather(acc plugins.Accumulator) error {
	k.Lock()
	defer k.Unlock()
	npoints := len(k.pointChan)
	for i := 0; i < npoints; i++ {
		point := <-k.pointChan
		acc.AddFields(point.Name(), point.Fields(), point.Tags(), point.Time())
	}
	return nil
}

func (d *MongodbData) add(acc plugins.Accumulator, key string, val interface{}) {
	acc.AddValuesWithTime(
		key,
		map[string]interface{}{
			"value": val,
		},
		d.Tags,
		d.StatLine.Time,
	)
}

// Flattens the map generated from the JSON object and stores its float values using a
// plugins.Accumulator. It ignores any non-float values.
// Parameters:
//     acc: the Accumulator to use
//     prefix: What the name of the measurement name should be prefixed by.
//     tags: telegraf tags to
func processResponse(acc plugins.Accumulator, prefix string, tags map[string]string, v interface{}) {
	switch t := v.(type) {
	case map[string]interface{}:
		for k, v := range t {
			processResponse(acc, prefix+"_"+k, tags, v)
		}
	case float64:
		acc.Add(prefix, v, tags)
	}
}

func (s *SystemStats) Gather(acc plugins.Accumulator) error {
	lv, err := s.ps.LoadAvg()
	if err != nil {
		return err
	}

	acc.Add("load1", lv.Load1, nil)
	acc.Add("load5", lv.Load5, nil)
	acc.Add("load15", lv.Load15, nil)

	return nil
}

// Import HTTP stat data into Telegraf system
func importMetric(r io.Reader, acc plugins.Accumulator, host string) (poolStat, error) {
	stats := make(poolStat)
	var currentPool string

	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		statLine := scanner.Text()
		keyvalue := strings.Split(statLine, ":")

		if len(keyvalue) < 2 {
			continue
		}
		fieldName := strings.Trim(keyvalue[0], " ")
		// We start to gather data for a new pool here
		if fieldName == PF_POOL {
			currentPool = strings.Trim(keyvalue[1], " ")
			stats[currentPool] = make(metric)
			continue
		}

		// Start to parse metric for current pool
		switch fieldName {
		case PF_ACCEPTED_CONN,
			PF_LISTEN_QUEUE,
			PF_MAX_LISTEN_QUEUE,
			PF_LISTEN_QUEUE_LEN,
			PF_IDLE_PROCESSES,
			PF_ACTIVE_PROCESSES,
			PF_TOTAL_PROCESSES,
			PF_MAX_ACTIVE_PROCESSES,
			PF_MAX_CHILDREN_REACHED,
			PF_SLOW_REQUESTS:
			fieldValue, err := strconv.ParseInt(strings.Trim(keyvalue[1], " "), 10, 64)
			if err == nil {
				stats[currentPool][fieldName] = fieldValue
			}
		}
	}

	// Finally, we push the pool metric
	for pool := range stats {
		tags := map[string]string{
			"url":  host,
			"pool": pool,
		}
		for k, v := range stats[pool] {
			acc.Add(strings.Replace(k, " ", "_", -1), v, tags)
		}
	}

	return stats, nil
}

func (s *NetIOStats) Gather(acc plugins.Accumulator) error {
	netio, err := s.ps.NetIO()
	if err != nil {
		return fmt.Errorf("error getting net io info: %s", err)
	}

	for _, io := range netio {
		if len(s.Interfaces) != 0 {
			var found bool

			for _, name := range s.Interfaces {
				if name == io.Name {
					found = true
					break
				}
			}

			if !found {
				continue
			}
		} else if !s.skipChecks {
			iface, err := net.InterfaceByName(io.Name)
			if err != nil {
				continue
			}

			if iface.Flags&net.FlagLoopback == net.FlagLoopback {
				continue
			}

			if iface.Flags&net.FlagUp == 0 {
				continue
			}
		}

		tags := map[string]string{
			"interface": io.Name,
		}

		acc.Add("bytes_sent", io.BytesSent, tags)
		acc.Add("bytes_recv", io.BytesRecv, tags)
		acc.Add("packets_sent", io.PacketsSent, tags)
		acc.Add("packets_recv", io.PacketsRecv, tags)
		acc.Add("err_in", io.Errin, tags)
		acc.Add("err_out", io.Errout, tags)
		acc.Add("drop_in", io.Dropin, tags)
		acc.Add("drop_out", io.Dropout, tags)
	}

	return nil
}

func (l *Lustre2) GetLustreProcStats(fileglob string, wanted_fields []*mapping, acc plugins.Accumulator) error {
	files, err := filepath.Glob(fileglob)
	if err != nil {
		return err
	}

	for _, file := range files {
		/* Turn /proc/fs/lustre/obdfilter/<ost_name>/stats and similar
		 * into just the object store target name
		 * Assumpion: the target name is always second to last,
		 * which is true in Lustre 2.1->2.5
		 */
		path := strings.Split(file, "/")
		name := path[len(path)-2]
		tags := map[string]string{
			"name": name,
		}

		lines, err := internal.ReadLines(file)
		if err != nil {
			return err
		}

		for _, line := range lines {
			fields := strings.Fields(line)

			for _, wanted := range wanted_fields {
				var data uint64
				if fields[0] == wanted.inProc {
					wanted_field := wanted.field
					// if not set, assume field[1]. Shouldn't be field[0], as
					// that's a string
					if wanted_field == 0 {
						wanted_field = 1
					}
					data, err = strconv.ParseUint((fields[wanted_field]), 10, 64)
					if err != nil {
						return err
					}
					report_name := wanted.inProc
					if wanted.reportAs != "" {
						report_name = wanted.reportAs
					}
					acc.Add(report_name, data, tags)

				}
			}
		}
	}
	return nil
}

func gatherQueues(r *RabbitMQ, serv *Server, acc plugins.Accumulator, errChan chan error) {
	// Gather information about queues
	queues := make([]Queue, 0)
	err := r.requestJSON(serv, "/api/queues", &queues)
	if err != nil {
		errChan <- err
		return
	}

	for _, queue := range queues {
		if !shouldGatherQueue(queue, serv) {
			continue
		}
		tags := map[string]string{
			"url":         serv.URL,
			"queue":       queue.Name,
			"vhost":       queue.Vhost,
			"node":        queue.Node,
			"durable":     strconv.FormatBool(queue.Durable),
			"auto_delete": strconv.FormatBool(queue.AutoDelete),
		}

		acc.AddFields(
			"queue",
			map[string]interface{}{
				// common information
				"consumers":            queue.Consumers,
				"consumer_utilisation": queue.ConsumerUtilisation,
				"memory":               queue.Memory,
				// messages information
				"messages":                  queue.Messages,
				"messages_ready":            queue.MessagesReady,
				"messages_unack":            queue.MessagesUnacknowledged,
				"messages_ack":              queue.MessageStats.Ack,
				"messages_ack_rate":         queue.MessageStats.AckDetails.Rate,
				"messages_deliver":          queue.MessageStats.Deliver,
				"messages_deliver_rate":     queue.MessageStats.DeliverDetails.Rate,
				"messages_deliver_get":      queue.MessageStats.DeliverGet,
				"messages_deliver_get_rate": queue.MessageStats.DeliverGetDetails.Rate,
				"messages_publish":          queue.MessageStats.Publish,
				"messages_publish_rate":     queue.MessageStats.PublishDetails.Rate,
				"messages_redeliver":        queue.MessageStats.Redeliver,
				"messages_redeliver_rate":   queue.MessageStats.RedeliverDetails.Rate,
			},
			tags,
		)
	}

	errChan <- nil
}

func (s *Trig) Gather(acc plugins.Accumulator) error {
	sinner := math.Sin((s.x*math.Pi)/5.0) * s.Amplitude
	cosinner := math.Cos((s.x*math.Pi)/5.0) * s.Amplitude

	fields := make(map[string]interface{})
	fields["sine"] = sinner
	fields["cosine"] = cosinner

	tags := make(map[string]string)

	s.x += 1.0
	acc.AddFields("trig", fields, tags)

	return nil
}

// Process backend server(redis/memcached) stats
func (ti *TwemproxyInstance) processServer(
	acc plugins.Accumulator,
	tags map[string]string,
	prefix string,
	data map[string]interface{},
) {
	for key, value := range data {
		switch key {
		default:
			if val, ok := value.(float64); ok {
				acc.Add(prefix+key, val, tags)
			}
		}
	}
}

func (j *Jolokia) Gather(acc plugins.Accumulator) error {

	context := j.Context //"/jolokia/read"
	servers := j.Servers
	metrics := j.Metrics
	tags := j.Tags

	if tags == nil {
		tags = map[string]string{}
	}

	for _, server := range servers {
		for _, metric := range metrics {

			measurement := metric.Name
			jmxPath := metric.Jmx

			tags["server"] = server.Name
			tags["port"] = server.Port
			tags["host"] = server.Host

			// Prepare URL
			requestUrl, err := url.Parse("http://" + server.Host + ":" +
				server.Port + context + jmxPath)
			if err != nil {
				return err
			}
			if server.Username != "" || server.Password != "" {
				requestUrl.User = url.UserPassword(server.Username, server.Password)
			}

			out, _ := j.getAttr(requestUrl)

			if values, ok := out["value"]; ok {
				switch values.(type) {
				case map[string]interface{}:
					acc.AddFields(measurement, metric.filterFields(values.(map[string]interface{})), tags)
				case interface{}:
					acc.Add(measurement, values.(interface{}), tags)
				}
			} else {
				fmt.Printf("Missing key 'value' in '%s' output response\n", requestUrl.String())
			}
		}
	}

	return nil
}

func (z *Zookeeper) gatherServer(address string, acc plugins.Accumulator) error {
	_, _, err := net.SplitHostPort(address)
	if err != nil {
		address = address + ":2181"
	}

	c, err := net.DialTimeout("tcp", address, defaultTimeout)
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		return err
	}
	defer c.Close()

	fmt.Fprintf(c, "%s\n", "mntr")

	rdr := bufio.NewReader(c)

	scanner := bufio.NewScanner(rdr)

	for scanner.Scan() {
		line := scanner.Text()

		re := regexp.MustCompile(`^zk_(\w+)\s+([\w\.\-]+)`)
		parts := re.FindStringSubmatch(string(line))

		service := strings.Split(address, ":")

		if len(parts) != 3 || len(service) != 2 {
			return fmt.Errorf("unexpected line in mntr response: %q", line)
		}

		tags := map[string]string{"server": service[0], "port": service[1]}

		measurement := strings.TrimPrefix(parts[1], "zk_")
		sValue := string(parts[2])

		iVal, err := strconv.ParseInt(sValue, 10, 64)
		if err == nil {
			acc.Add(measurement, iVal, tags)
		} else {
			acc.Add(measurement, sValue, tags)
		}
	}

	return nil
}

func (s *SwapStats) Gather(acc plugins.Accumulator) error {
	swap, err := s.ps.SwapStat()
	if err != nil {
		return fmt.Errorf("error getting swap memory info: %s", err)
	}

	swaptags := map[string]string(nil)

	acc.Add("total", swap.Total, swaptags)
	acc.Add("used", swap.Used, swaptags)
	acc.Add("free", swap.Free, swaptags)
	acc.Add("used_percent", swap.UsedPercent, swaptags)
	acc.Add("in", swap.Sin, swaptags)
	acc.Add("out", swap.Sout, swaptags)

	return nil
}