doghouse: do not share http client

doghouse/appengine/checker.go

@@ -9,18 +9,19 @@ import (
 	"net/url"
 	"strings"
 
+	"contrib.go.opencensus.io/exporter/stackdriver/propagation"
 	"github.com/reviewdog/reviewdog/doghouse"
 	"github.com/reviewdog/reviewdog/doghouse/server"
 	"github.com/reviewdog/reviewdog/doghouse/server/ciutil"
 	"github.com/reviewdog/reviewdog/doghouse/server/storage"
+	"go.opencensus.io/plugin/ochttp"
 )
 
 type githubChecker struct {
 	privateKey       []byte
 	integrationID    int
 	ghInstStore      storage.GitHubInstallationStore
 	ghRepoTokenStore storage.GitHubRepositoryTokenStore
-	httpCli          *http.Client
 }
 
 func (gc *githubChecker) handleCheck(w http.ResponseWriter, r *http.Request) {
@@ -46,7 +47,12 @@ func (gc *githubChecker) handleCheck(w http.ResponseWriter, r *http.Request) {
 		PrivateKey:    gc.privateKey,
 		IntegrationID: gc.integrationID,
 		RepoOwner:     req.Owner,
-		Client:        gc.httpCli,
+		Client: &http.Client{
+			Transport: &ochttp.Transport{
+				// Use Google Cloud propagation format.
+				Propagation: &propagation.HTTPFormat{},
+			},
+		},
 	}
 
 	gh, err := server.NewGitHubClient(ctx, opt)

doghouse/appengine/main.go

@@ -73,13 +73,6 @@ func main() {
 	ghInstStore := storage.GitHubInstallationDatastore{}
 	ghRepoTokenStore := storage.GitHubRepoTokenDatastore{}
 
-	httpCli := &http.Client{
-		Transport: &ochttp.Transport{
-			// Use Google Cloud propagation format.
-			Propagation: &propagation.HTTPFormat{},
-		},
-	}
-
 	ghHandler := NewGitHubHandler(
 		mustGetenv("GITHUB_CLIENT_ID"),
 		mustGetenv("GITHUB_CLIENT_SECRET"),
@@ -93,7 +86,6 @@ func main() {
 		integrationID:    integrationID,
 		ghInstStore:      &ghInstStore,
 		ghRepoTokenStore: &ghRepoTokenStore,
-		httpCli:          httpCli,
 	}
 
 	ghWebhookHandler := githubWebhookHandler{