Replace usage of http.DefaultClient and http.DefaultTransport (#104135)

Remove usage of http.DefaultClient and http.DefaultTransport

Part of grafana/data-sources#484

pkg/api/login_oauth_test.go

@@ -16,20 +16,6 @@ import (
 	"github.com/grafana/grafana/pkg/setting"
 )
 
-func setClientWithoutRedirectFollow(t *testing.T) {
-	t.Helper()
-	old := http.DefaultClient
-	http.DefaultClient = &http.Client{
-		CheckRedirect: func(req *http.Request, via []*http.Request) error {
-			return http.ErrUseLastResponse
-		},
-	}
-
-	t.Cleanup(func() {
-		http.DefaultClient = old
-	})
-}
-
 func TestOAuthLogin_Redirect(t *testing.T) {
 	type testCase struct {
 		desc             string
@@ -79,7 +65,9 @@ func TestOAuthLogin_Redirect(t *testing.T) {
 			})
 
 			// we need to prevent the http.Client from following redirects
-			setClientWithoutRedirectFollow(t)
+			server.HttpClient.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+				return http.ErrUseLastResponse
+			}
 
 			res, err := server.Send(server.NewGetRequest("/login/generic_oauth"))
 			require.NoError(t, err)
@@ -155,7 +143,9 @@ func TestOAuthLogin_AuthorizationCode(t *testing.T) {
 			})
 
 			// we need to prevent the http.Client from following redirects
-			setClientWithoutRedirectFollow(t)
+			server.HttpClient.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+				return http.ErrUseLastResponse
+			}
 
 			res, err := server.Send(server.NewGetRequest("/login/generic_oauth?code=code"))
 			require.NoError(t, err)
@@ -198,8 +188,9 @@ func TestOAuthLogin_Error(t *testing.T) {
 		hs.log = log.NewNopLogger()
 		hs.SecretsService = fakes.NewFakeSecretsService()
 	})
-
-	setClientWithoutRedirectFollow(t)
+	server.HttpClient.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+		return http.ErrUseLastResponse
+	}
 
 	res, err := server.Send(server.NewGetRequest("/login/azuread?error=someerror"))
 	require.NoError(t, err)

pkg/api/webassets/webassets.go

@@ -13,6 +13,7 @@ import (
 	"github.com/grafana/grafana/pkg/api/dtos"
 	"github.com/grafana/grafana/pkg/services/licensing"
 	"github.com/grafana/grafana/pkg/setting"
+	"github.com/grafana/grafana/pkg/util/httpclient"
 )
 
 type ManifestInfo struct {
@@ -36,6 +37,7 @@ type EntryPointInfo struct {
 var (
 	entryPointAssetsCacheMu sync.RWMutex           // guard entryPointAssetsCache
 	entryPointAssetsCache   *dtos.EntryPointAssets // TODO: get rid of global state
+	httpClient              = httpclient.New()
 )
 
 func GetWebAssets(ctx context.Context, cfg *setting.Cfg, license licensing.Licensing) (*dtos.EntryPointAssets, error) {
@@ -88,7 +90,7 @@ func readWebAssetsFromCDN(ctx context.Context, baseURL string) (*dtos.EntryPoint
 	if err != nil {
 		return nil, err
 	}
-	response, err := http.DefaultClient.Do(req)
+	response, err := httpClient.Do(req)
 	if err != nil {
 		return nil, err
 	}