Amon output

closes #350

outputs/amon/amon.go

@@ -0,0 +1,148 @@
+package amon
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"strings"
+
+	"github.com/influxdb/influxdb/client/v2"
+	"github.com/influxdb/telegraf/duration"
+	"github.com/influxdb/telegraf/outputs"
+)
+
+type Amon struct {
+	ServerKey    string
+	AmonInstance string
+	Timeout      duration.Duration
+
+	client *http.Client
+}
+
+var sampleConfig = `
+  # Amon Server Key
+  server_key = "my-server-key" # required.
+
+  # Amon Instance URL
+  amon_instance = "https://youramoninstance" # required
+
+  # Connection timeout.
+  # timeout = "5s"
+`
+
+type TimeSeries struct {
+	Series []*Metric `json:"series"`
+}
+
+type Metric struct {
+	Metric string   `json:"metric"`
+	Points [1]Point `json:"points"`
+}
+
+type Point [2]float64
+
+func (a *Amon) Connect() error {
+	if a.ServerKey == "" || a.AmonInstance == "" {
+		return fmt.Errorf("serverkey and amon_instance are required fields for amon output")
+	}
+	a.client = &http.Client{
+		Timeout: a.Timeout.Duration,
+	}
+	return nil
+}
+
+func (a *Amon) Write(points []*client.Point) error {
+	if len(points) == 0 {
+		return nil
+	}
+	ts := TimeSeries{}
+	var tempSeries = make([]*Metric, len(points))
+	var acceptablePoints = 0
+	for _, pt := range points {
+		metric := &Metric{
+			Metric: strings.Replace(pt.Name(), "_", ".", -1),
+		}
+		if p, err := buildPoint(pt); err == nil {
+			metric.Points[0] = p
+			tempSeries[acceptablePoints] = metric
+			acceptablePoints += 1
+		} else {
+			log.Printf("unable to build Metric for %s, skipping\n", pt.Name())
+		}
+	}
+	ts.Series = make([]*Metric, acceptablePoints)
+	copy(ts.Series, tempSeries[0:])
+	tsBytes, err := json.Marshal(ts)
+	if err != nil {
+		return fmt.Errorf("unable to marshal TimeSeries, %s\n", err.Error())
+	}
+	req, err := http.NewRequest("POST", a.authenticatedUrl(), bytes.NewBuffer(tsBytes))
+	if err != nil {
+		return fmt.Errorf("unable to create http.Request, %s\n", err.Error())
+	}
+	req.Header.Add("Content-Type", "application/json")
+
+	resp, err := a.client.Do(req)
+	if err != nil {
+		return fmt.Errorf("error POSTing metrics, %s\n", err.Error())
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode > 209 {
+		return fmt.Errorf("received bad status code, %d\n", resp.StatusCode)
+	}
+
+	return nil
+}
+
+func (a *Amon) SampleConfig() string {
+	return sampleConfig
+}
+
+func (a *Amon) Description() string {
+	return "Configuration for Amon Server to send metrics to."
+}
+
+func (a *Amon) authenticatedUrl() string {
+
+	return fmt.Sprintf("%s/api/system/%s", a.AmonInstance, a.ServerKey)
+}
+
+func buildPoint(pt *client.Point) (Point, error) {
+	var p Point
+	if err := p.setValue(pt.Fields()["value"]); err != nil {
+		return p, fmt.Errorf("unable to extract value from Fields, %s", err.Error())
+	}
+	p[0] = float64(pt.Time().Unix())
+	return p, nil
+}
+
+func (p *Point) setValue(v interface{}) error {
+	switch d := v.(type) {
+	case int:
+		p[1] = float64(int(d))
+	case int32:
+		p[1] = float64(int32(d))
+	case int64:
+		p[1] = float64(int64(d))
+	case float32:
+		p[1] = float64(d)
+	case float64:
+		p[1] = float64(d)
+	default:
+		return fmt.Errorf("undeterminable type")
+	}
+	return nil
+}
+
+func (a *Amon) Close() error {
+	return nil
+}
+
+func init() {
+	outputs.Add("amon", func() outputs.Output {
+		return &Amon{}
+	})
+}