Share azureauth between prometheus clients (#58122)

* Move azureauth to upper package

* Refactor http transport options

pkg/tsdb/prometheus/client/transport.go

@@ -0,0 +1,79 @@
+package client
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	sdkhttpclient "github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/setting"
+	"github.com/grafana/grafana/pkg/tsdb/prometheus/azureauth"
+	"github.com/grafana/grafana/pkg/tsdb/prometheus/middleware"
+	"github.com/grafana/grafana/pkg/tsdb/prometheus/utils"
+	"github.com/grafana/grafana/pkg/util/maputil"
+	"github.com/prometheus/client_golang/api"
+	apiv1 "github.com/prometheus/client_golang/api/prometheus/v1"
+)
+
+// CreateTransportOptions creates options for the http client. Probably should be shared and should not live in the
+// buffered package.
+func CreateTransportOptions(settings backend.DataSourceInstanceSettings, cfg *setting.Cfg, logger log.Logger) (*sdkhttpclient.Options, error) {
+	opts, err := settings.HTTPClientOptions()
+	if err != nil {
+		return nil, err
+	}
+
+	jsonData, err := utils.GetJsonData(settings)
+	if err != nil {
+		return nil, fmt.Errorf("error reading settings: %w", err)
+	}
+	httpMethod, _ := maputil.GetStringOptional(jsonData, "httpMethod")
+
+	opts.Middlewares = middlewares(logger, httpMethod)
+
+	// Set SigV4 service namespace
+	if opts.SigV4 != nil {
+		opts.SigV4.Service = "aps"
+	}
+
+	// Set Azure authentication
+	if cfg.AzureAuthEnabled {
+		err = azureauth.ConfigureAzureAuthentication(settings, cfg.Azure, &opts)
+		if err != nil {
+			return nil, fmt.Errorf("error configuring Azure auth: %v", err)
+		}
+	}
+
+	return &opts, nil
+}
+
+func CreateAPIClient(roundTripper http.RoundTripper, url string) (apiv1.API, error) {
+	cfg := api.Config{
+		Address:      url,
+		RoundTripper: roundTripper,
+	}
+
+	client, err := api.NewClient(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return apiv1.NewAPI(client), nil
+}
+
+func middlewares(logger log.Logger, httpMethod string) []sdkhttpclient.Middleware {
+	middlewares := []sdkhttpclient.Middleware{
+		// TODO: probably isn't needed anymore and should by done by http infra code
+		middleware.CustomQueryParameters(logger),
+		sdkhttpclient.CustomHeadersMiddleware(),
+	}
+
+	// Needed to control GET vs POST method of the requests
+	if strings.ToLower(httpMethod) == "get" {
+		middlewares = append(middlewares, middleware.ForceHttpGet(logger))
+	}
+
+	return middlewares
+}

pkg/tsdb/prometheus/client/transport_test.go

@@ -0,0 +1,44 @@
+package client
+
+import (
+	"testing"
+
+	"github.com/grafana/grafana-azure-sdk-go/azsettings"
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/grafana/grafana/pkg/infra/log/logtest"
+	"github.com/grafana/grafana/pkg/setting"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreateTransportOptions(t *testing.T) {
+	t.Run("creates correct options object", func(t *testing.T) {
+		settings := backend.DataSourceInstanceSettings{
+			BasicAuthEnabled: false,
+			BasicAuthUser:    "",
+			JSONData:         []byte(`{"httpHeaderName1": "foo"}`),
+			DecryptedSecureJSONData: map[string]string{
+				"httpHeaderValue1": "bar",
+			},
+		}
+		opts, err := CreateTransportOptions(settings, &setting.Cfg{}, &logtest.Fake{})
+		require.NoError(t, err)
+		require.Equal(t, map[string]string{"foo": "bar"}, opts.Headers)
+		require.Equal(t, 2, len(opts.Middlewares))
+	})
+
+	t.Run("add azure credentials if configured", func(t *testing.T) {
+		settings := backend.DataSourceInstanceSettings{
+			BasicAuthEnabled: false,
+			BasicAuthUser:    "",
+			JSONData: []byte(`{
+				"azureCredentials": {
+					"authType": "msi"
+				}
+			}`),
+			DecryptedSecureJSONData: map[string]string{},
+		}
+		opts, err := CreateTransportOptions(settings, &setting.Cfg{AzureAuthEnabled: true, Azure: &azsettings.AzureSettings{}}, &logtest.Fake{})
+		require.NoError(t, err)
+		require.Equal(t, 3, len(opts.Middlewares))
+	})
+}