Add ReportMetrics to azureidentity.go

pkg/common/oras/authprovider/azure/azureidentity.go

@@ -19,6 +19,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"github.com/ratify-project/ratify/pkg/metrics"
 	"os"
 	"time"
 
@@ -136,11 +137,16 @@ func (d *azureManagedIdentityAuthProvider) Provide(ctx context.Context, artifact
 
 	// create registry client and exchange AAD token for registry refresh token
 	refreshTokenClient := containerregistry.NewRefreshTokensClient(serverURL)
+	// The time to start recording the token exchange process
+	startTime := time.Now()
 	rt, err := refreshTokenClient.GetFromExchange(ctx, "access_token", artifactHostName, d.tenantID, "", d.identityToken.Token)
 	if err != nil {
 		return provider.AuthConfig{}, re.ErrorCodeAuthDenied.NewError(re.AuthProvider, "", re.AzureManagedIdentityLink, err, "failed to get refresh token for container registry by azure managed identity token", re.HideStackTrace)
 	}
 
+	// Report the duration of the token exchange to the metrics system
+	metrics.ReportACRExchangeDuration(ctx, time.Since(startTime).Milliseconds(), artifactHostName)
+
 	expiresOn := getACRExpiryIfEarlier(d.identityToken.ExpiresOn)
 
 	authConfig := provider.AuthConfig{