OpenTracing for Fission (#1079)

Added Opentracing integration using opencensus libraries for all Fission components.

environments/fetcher/client/client.go

@@ -2,6 +2,7 @@ package client
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"io/ioutil"
 	"log"
@@ -9,18 +10,25 @@ import (
 	"strings"
 	"time"
 
+	"go.opencensus.io/plugin/ochttp"
+	"golang.org/x/net/context/ctxhttp"
+
 	"github.com/fission/fission"
 )
 
 type (
 	Client struct {
-		url string
+		url        string
+		httpClient *http.Client
 	}
 )
 
 func MakeClient(fetcherUrl string) *Client {
 	return &Client{
 		url: strings.TrimSuffix(fetcherUrl, "/"),
+		httpClient: &http.Client{
+			Transport: &ochttp.Transport{},
+		},
 	}
 }
 
@@ -36,18 +44,18 @@ func (c *Client) getUploadUrl() string {
 	return c.url + "/upload"
 }
 
-func (c *Client) Specialize(req *fission.FunctionSpecializeRequest) error {
-	_, err := sendRequest(req, c.getSpecializeUrl())
+func (c *Client) Specialize(ctx context.Context, req *fission.FunctionSpecializeRequest) error {
+	_, err := sendRequest(ctx, c.httpClient, req, c.getSpecializeUrl())
 	return err
 }
 
-func (c *Client) Fetch(fr *fission.FunctionFetchRequest) error {
-	_, err := sendRequest(fr, c.getFetchUrl())
+func (c *Client) Fetch(ctx context.Context, fr *fission.FunctionFetchRequest) error {
+	_, err := sendRequest(ctx, c.httpClient, fr, c.getFetchUrl())
 	return err
 }
 
-func (c *Client) Upload(fr *fission.ArchiveUploadRequest) (*fission.ArchiveUploadResponse, error) {
-	body, err := sendRequest(fr, c.getUploadUrl())
+func (c *Client) Upload(ctx context.Context, fr *fission.ArchiveUploadRequest) (*fission.ArchiveUploadResponse, error) {
+	body, err := sendRequest(ctx, c.httpClient, fr, c.getUploadUrl())
 
 	uploadResp := fission.ArchiveUploadResponse{}
 	err = json.Unmarshal(body, &uploadResp)
@@ -58,7 +66,7 @@ func (c *Client) Upload(fr *fission.ArchiveUploadRequest) (*fission.ArchiveUploa
 	return &uploadResp, nil
 }
 
-func sendRequest(req interface{}, url string) ([]byte, error) {
+func sendRequest(ctx context.Context, httpClient *http.Client, req interface{}, url string) ([]byte, error) {
 	body, err := json.Marshal(req)
 	if err != nil {
 		return nil, err
@@ -68,7 +76,7 @@ func sendRequest(req interface{}, url string) ([]byte, error) {
 	var resp *http.Response
 
 	for i := 0; i < maxRetries; i++ {
-		resp, err = http.Post(url, "application/json", bytes.NewReader(body))
+		resp, err = ctxhttp.Post(ctx, httpClient, url, "application/json", bytes.NewReader(body))
 
 		if err == nil {
 			if resp.StatusCode == 200 {