Make Prepare a method of a Provider

internal/sinks/provider/http.go

@@ -2,10 +2,12 @@ package provider
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"net/http"
 	"time"
 
+	"github.com/hashicorp/nomad/api"
 	"github.com/sirupsen/logrus"
 )
 
@@ -63,6 +65,15 @@ func NewHTTP(opts HTTPOpts) (*HTTPManager, error) {
 	return httpMgr, nil
 }
 
+// Prepare takes batches of events and returns JSON encoding of the same.
+func (m *HTTPManager) Prepare(events []api.Event) ([]byte, error) {
+	data, err := json.Marshal(events)
+	if err != nil {
+		return nil, err
+	}
+	return data, nil
+}
+
 // Push sends out events to an HTTP Endpoint.
 func (m *HTTPManager) Push(data []byte) error {
 	req, err := http.NewRequest("POST", m.rootURL, bytes.NewBuffer(data))

internal/sinks/provider/provider.go

@@ -1,8 +1,12 @@
 package provider
 
+import "github.com/hashicorp/nomad/api"
+
 type Provider interface {
 	// Name returns the name of the Provider.
 	Name() string
+	// Prepare returns a prepared payload as an array of bytes
+	Prepare([]api.Event) ([]byte, error)
 	// Push pushes a batch of event to upstream. The implementation varies across providers.
 	Push([]byte) error
 	// Ping implements a healthcheck.

internal/sinks/worker.go

@@ -2,7 +2,6 @@ package sink
 
 import (
 	"context"
-	"encoding/json"
 	"time"
 
 	"github.com/hashicorp/nomad/api"
@@ -74,26 +73,17 @@ func (w *Worker) flush(batch []api.Event) {
 		return
 	}
 
-	data, err := prepareJSON(batch)
-	if err != nil {
-		w.log.WithField("batch_len", len(batch)).WithError(err).Error("error while json marshall")
-	}
-
 	w.log.WithField("batch_len", len(batch)).Info("pushing events to providers")
 	for _, prov := range w.providers {
+		data, err := prov.Prepare(batch)
+		if err != nil {
+			w.log.WithField("batch_len", len(batch)).WithError(err).Error("error while json marshall")
+		}
+
 		err = prov.Push(data)
 		if err != nil {
 			// TODO: Handle the error better.
 			w.log.WithError(err).Error("error while pushing to provider")
 		}
 	}
 }
-
-// prepareJSON takes batches of events and returns JSON encoding of the same.
-func prepareJSON(events []api.Event) ([]byte, error) {
-	data, err := json.Marshal(events)
-	if err != nil {
-		return nil, err
-	}
-	return data, nil
-}