Shared Azure middleware between Azure Monitor and Prometheus datasources (#46002)

* Scopes in Azure middleware

* Enable Azure middleware without feature flag

* Use common Azure middleware in Azure Monitor

* Apply feature flag to JsonData configuration of Azure auth

* Enforce feature flag in Prometheus datasource

* Prometheus provider tests

* Datasource service tests

* Fix http client provider tests

* Pass sdkhttpclient.Options by reference

* Add middleware to httpclient.Options

* Remove dependency on Grafana settings

* Unit-tests updated

* Fix ds_proxy_test

* Fix service_test

pkg/tsdb/azuremonitor/httpclient_test.go

@@ -1,17 +1,21 @@
 package azuremonitor
 
 import (
+	"crypto/tls"
+	"net/http"
 	"testing"
 
+	sdkhttpclient "github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
+	"github.com/grafana/grafana/pkg/infra/httpclient"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/tsdb/azuremonitor/azcredentials"
 	"github.com/grafana/grafana/pkg/tsdb/azuremonitor/deprecated"
 	"github.com/grafana/grafana/pkg/tsdb/azuremonitor/types"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
-func Test_httpCliProvider(t *testing.T) {
-	cfg := &setting.Cfg{}
+func TestHttpClient_Middlewares(t *testing.T) {
 	tests := []struct {
 		name                string
 		route               types.AzRoute
@@ -19,18 +23,6 @@ func Test_httpCliProvider(t *testing.T) {
 		expectedMiddlewares int
 		Err                 require.ErrorAssertionFunc
 	}{
-		{
-			name: "creates an HTTP client with a middleware due to the scope",
-			route: types.AzRoute{
-				URL:    "http://route",
-				Scopes: []string{"http://route/.default"},
-			},
-			model: types.DatasourceInfo{
-				Credentials: &azcredentials.AzureClientSecretCredentials{},
-			},
-			expectedMiddlewares: 1,
-			Err:                 require.NoError,
-		},
 		{
 			name: "creates an HTTP client with a middleware due to an app key",
 			route: types.AzRoute{
@@ -61,7 +53,7 @@ func Test_httpCliProvider(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			m, err := getMiddlewares(tt.route, tt.model, cfg)
+			m, err := getMiddlewares(tt.route, tt.model)
 			require.NoError(t, err)
 
 			// Cannot test that the cli middleware works properly since the azcore sdk
@@ -72,3 +64,63 @@ func Test_httpCliProvider(t *testing.T) {
 		})
 	}
 }
+
+func TestHttpClient_AzureCredentials(t *testing.T) {
+	model := types.DatasourceInfo{
+		Credentials: &azcredentials.AzureManagedIdentityCredentials{},
+	}
+
+	cfg := &setting.Cfg{}
+	provider := &fakeHttpClientProvider{}
+
+	t.Run("should have Azure middleware when scopes provided", func(t *testing.T) {
+		route := types.AzRoute{
+			URL:    deprecated.AzAppInsights.URL,
+			Scopes: []string{"https://management.azure.com/.default"},
+		}
+
+		_, err := newHTTPClient(route, model, cfg, provider)
+		require.NoError(t, err)
+
+		require.NotNil(t, provider.opts)
+		require.NotNil(t, provider.opts.Middlewares)
+		assert.Len(t, provider.opts.Middlewares, 1)
+	})
+
+	t.Run("should not have Azure middleware when scopes are not provided", func(t *testing.T) {
+		route := types.AzRoute{
+			URL:    deprecated.AzAppInsights.URL,
+			Scopes: []string{},
+		}
+
+		_, err := newHTTPClient(route, model, cfg, provider)
+		require.NoError(t, err)
+
+		assert.NotNil(t, provider.opts)
+
+		if provider.opts.Middlewares != nil {
+			assert.Len(t, provider.opts.Middlewares, 0)
+		}
+	})
+}
+
+type fakeHttpClientProvider struct {
+	httpclient.Provider
+
+	opts sdkhttpclient.Options
+}
+
+func (p *fakeHttpClientProvider) New(opts ...sdkhttpclient.Options) (*http.Client, error) {
+	p.opts = opts[0]
+	return nil, nil
+}
+
+func (p *fakeHttpClientProvider) GetTransport(opts ...sdkhttpclient.Options) (http.RoundTripper, error) {
+	p.opts = opts[0]
+	return nil, nil
+}
+
+func (p *fakeHttpClientProvider) GetTLSConfig(opts ...sdkhttpclient.Options) (*tls.Config, error) {
+	p.opts = opts[0]
+	return nil, nil
+}