Plugins: Remove various custom headers logic (#54146) (#54284)

Removes various custom headers logic sprinkled around in the backend.
It should automatically be applied to outgoing HTTP requests via the
CustomHeadersMiddleware.
This also removes decryption of SecureJSONData to populate custom
headers in ngalert which seemed to have caused a ton of CPU usage.

(cherry picked from commit 87afd9cadc)

pkg/tsdb/legacydata/service/service.go

@@ -3,12 +3,10 @@ package service
 import (
 	"context"
 	"fmt"
-	"strings"
 	"time"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 
-	"github.com/grafana/grafana/pkg/components/simplejson"
 	"github.com/grafana/grafana/pkg/plugins"
 	"github.com/grafana/grafana/pkg/plugins/adapters"
 	"github.com/grafana/grafana/pkg/services/datasources"
@@ -16,11 +14,6 @@ import (
 	"github.com/grafana/grafana/pkg/tsdb/legacydata"
 )
 
-const (
-	headerName  = "httpHeaderName"
-	headerValue = "httpHeaderValue"
-)
-
 var oAuthIsOAuthPassThruEnabledFunc = func(oAuthTokenService oauthtoken.OAuthTokenService, ds *datasources.DataSource) bool {
 	return oAuthTokenService.IsOAuthPassThruEnabled(ds)
 }
@@ -126,11 +119,6 @@ func generateRequest(ctx context.Context, ds *datasources.DataSource, decryptedJ
 		Headers: query.Headers,
 	}
 
-	// Apply Configured Custom Headers to query request.
-	for k, v := range customHeaders(ds.JsonData, instanceSettings.DecryptedSecureJSONData) {
-		req.Headers[k] = v
-	}
-
 	for _, q := range query.Queries {
 		modelJSON, err := q.Model.MarshalJSON()
 		if err != nil {
@@ -151,24 +139,4 @@ func generateRequest(ctx context.Context, ds *datasources.DataSource, decryptedJ
 	return req, nil
 }
 
-func customHeaders(jsonData *simplejson.Json, decryptedJsonData map[string]string) map[string]string {
-	if jsonData == nil {
-		return nil
-	}
-
-	data := jsonData.MustMap()
-
-	headers := map[string]string{}
-	for k := range data {
-		if strings.HasPrefix(k, headerName) {
-			if header, ok := data[k].(string); ok {
-				valueKey := strings.ReplaceAll(k, headerName, headerValue)
-				headers[header] = decryptedJsonData[valueKey]
-			}
-		}
-	}
-
-	return headers
-}
-
 var _ legacydata.RequestHandler = &Service{}

pkg/tsdb/legacydata/service/service_test.go

@@ -61,39 +61,6 @@ func TestHandleRequest(t *testing.T) {
 	})
 }
 
-func Test_generateRequest(t *testing.T) {
-	t.Run("Should attach custom headers to request if present", func(t *testing.T) {
-		jsonData := simplejson.New()
-		jsonData.Set(headerName+"testOne", "x-test-one")
-		jsonData.Set("testOne", "x-test-wrong")
-		jsonData.Set(headerName+"testTwo", "x-test-two")
-
-		decryptedJsonData := map[string]string{
-			headerValue + "testOne": "secret-value-one",
-			headerValue + "testTwo": "secret-value-two",
-			"something":             "else",
-		}
-
-		ds := &datasources.DataSource{Id: 12, Type: "unregisteredType", JsonData: jsonData}
-		query := legacydata.DataQuery{
-			TimeRange: &legacydata.DataTimeRange{},
-			Queries: []legacydata.DataSubQuery{
-				{RefID: "A", DataSource: &datasources.DataSource{Id: 1, Type: "test"}, Model: simplejson.New()},
-				{RefID: "B", DataSource: &datasources.DataSource{Id: 1, Type: "test"}, Model: simplejson.New()},
-			},
-		}
-
-		req, err := generateRequest(context.Background(), ds, decryptedJsonData, query)
-		require.NoError(t, err)
-		require.NotNil(t, req)
-		require.EqualValues(t,
-			map[string]string{
-				"x-test-one": "secret-value-one",
-				"x-test-two": "secret-value-two",
-			}, req.Headers)
-	})
-}
-
 type fakePluginsClient struct {
 	plugins.Client
 	backend.QueryDataHandlerFunc