Add input plugin for rollbar service. (#1247)

* Report rollbar events.

Signed-off-by: Cyril Duez <cyril@stormz.me>
Signed-off-by: François de Metz <francois@stormz.me>

* Fix indent with go fmt.

* Add test for rollbar webhooks.

* Report more data from new_item event.

* Handle new deploy webhook.

Signed-off-by: Cyril Duez <cyril@stormz.me>
Signed-off-by: François de Metz <francois@stormz.me>

* Update default port.

* Add readme.

* Add rollbar_webhooks to the readme.

* Add rollbar_webhooks to plugins list.

* Add tag level for new_item event.

* Update readme.

* Update changelog.

plugins/inputs/rollbar_webhooks/rollbar_webhooks.go

@@ -0,0 +1,119 @@
+package rollbar_webhooks
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/gorilla/mux"
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+func init() {
+	inputs.Add("rollbar_webhooks", func() telegraf.Input { return NewRollbarWebhooks() })
+}
+
+type RollbarWebhooks struct {
+	ServiceAddress string
+	// Lock for the struct
+	sync.Mutex
+	// Events buffer to store events between Gather calls
+	events []Event
+}
+
+func NewRollbarWebhooks() *RollbarWebhooks {
+	return &RollbarWebhooks{}
+}
+
+func (rb *RollbarWebhooks) SampleConfig() string {
+	return `
+  ## Address and port to host Webhook listener on
+  service_address = ":1619"
+`
+}
+
+func (rb *RollbarWebhooks) Description() string {
+	return "A Rollbar Webhook Event collector"
+}
+
+func (rb *RollbarWebhooks) Gather(acc telegraf.Accumulator) error {
+	rb.Lock()
+	defer rb.Unlock()
+	for _, event := range rb.events {
+		acc.AddFields("rollbar_webhooks", event.Fields(), event.Tags(), time.Now())
+	}
+	rb.events = make([]Event, 0)
+	return nil
+}
+
+func (rb *RollbarWebhooks) Listen() {
+	r := mux.NewRouter()
+	r.HandleFunc("/", rb.eventHandler).Methods("POST")
+	err := http.ListenAndServe(fmt.Sprintf("%s", rb.ServiceAddress), r)
+	if err != nil {
+		log.Printf("Error starting server: %v", err)
+	}
+}
+
+func (rb *RollbarWebhooks) Start(_ telegraf.Accumulator) error {
+	go rb.Listen()
+	log.Printf("Started the rollbar_webhooks service on %s\n", rb.ServiceAddress)
+	return nil
+}
+
+func (rb *RollbarWebhooks) Stop() {
+	log.Println("Stopping the rbWebhooks service")
+}
+
+func (rb *RollbarWebhooks) eventHandler(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+	data, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	dummyEvent := &DummyEvent{}
+	err = json.Unmarshal(data, dummyEvent)
+	if err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	event, err := NewEvent(dummyEvent, data)
+	if err != nil {
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	rb.Lock()
+	rb.events = append(rb.events, event)
+	rb.Unlock()
+
+	w.WriteHeader(http.StatusOK)
+}
+
+func generateEvent(event Event, data []byte) (Event, error) {
+	err := json.Unmarshal(data, event)
+	if err != nil {
+		return nil, err
+	}
+	return event, nil
+}
+
+func NewEvent(dummyEvent *DummyEvent, data []byte) (Event, error) {
+	switch dummyEvent.EventName {
+	case "new_item":
+		return generateEvent(&NewItem{}, data)
+	case "deploy":
+		return generateEvent(&Deploy{}, data)
+	default:
+		return nil, errors.New("Not implemented type: " + dummyEvent.EventName)
+	}
+}