Use specific credential rather than the credential chain for Azure

Use specific credential rather than the credential chain for Azure

Signed-off-by: Wenkai Yin(尹文开) <yinw@vmware.com>

pkg/util/azure/credential.go

@@ -26,54 +26,36 @@ import (
 	"github.com/pkg/errors"
 )
 
-// NewCredential chains the config credential , workload identity credential , managed identity credential
+// NewCredential constructs a Credential that tries the config credential, workload identity credential
+// and managed identity credential according to the provided creds.
 func NewCredential(creds map[string]string, options policy.ClientOptions) (azcore.TokenCredential, error) {
-	var (
-		credential []azcore.TokenCredential
-		errMsgs    []string
-	)
-
 	additionalTenants := []string{}
 	if tenants := creds[CredentialKeyAdditionallyAllowedTenants]; tenants != "" {
 		additionalTenants = strings.Split(tenants, ";")
 	}
 
 	// config credential
-	cfgCred, err := newConfigCredential(creds, configCredentialOptions{
-		ClientOptions:              options,
-		AdditionallyAllowedTenants: additionalTenants,
-	})
-	if err == nil {
-		credential = append(credential, cfgCred)
-	} else {
-		errMsgs = append(errMsgs, err.Error())
+	if len(creds[CredentialKeyClientSecret]) > 0 ||
+		len(creds[CredentialKeyClientCertificate]) > 0 ||
+		len(creds[CredentialKeyClientCertificatePath]) > 0 ||
+		len(creds[CredentialKeyUsername]) > 0 {
+		return newConfigCredential(creds, configCredentialOptions{
+			ClientOptions:              options,
+			AdditionallyAllowedTenants: additionalTenants,
+		})
 	}
 
 	// workload identity credential
-	wic, err := azidentity.NewWorkloadIdentityCredential(&azidentity.WorkloadIdentityCredentialOptions{
-		AdditionallyAllowedTenants: additionalTenants,
-		ClientOptions:              options,
-	})
-	if err == nil {
-		credential = append(credential, wic)
-	} else {
-		errMsgs = append(errMsgs, err.Error())
+	if len(os.Getenv("AZURE_FEDERATED_TOKEN_FILE")) > 0 {
+		return azidentity.NewWorkloadIdentityCredential(&azidentity.WorkloadIdentityCredentialOptions{
+			AdditionallyAllowedTenants: additionalTenants,
+			ClientOptions:              options,
+		})
 	}
 
-	//managed identity credential
+	// managed identity credential
 	o := &azidentity.ManagedIdentityCredentialOptions{ClientOptions: options, ID: azidentity.ClientID(creds[CredentialKeyClientID])}
-	msi, err := azidentity.NewManagedIdentityCredential(o)
-	if err == nil {
-		credential = append(credential, msi)
-	} else {
-		errMsgs = append(errMsgs, err.Error())
-	}
-
-	if len(credential) == 0 {
-		return nil, errors.Errorf("failed to create Azure credential: %s", strings.Join(errMsgs, "\n\t"))
-	}
-
-	return azidentity.NewChainedTokenCredential(credential, nil)
+	return azidentity.NewManagedIdentityCredential(o)
 }
 
 type configCredentialOptions struct {

pkg/util/azure/credential_test.go

@@ -17,36 +17,63 @@ limitations under the License.
 package azure
 
 import (
-	"context"
+	"os"
 	"testing"
-	"time"
 
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
 	"github.com/Azure/azure-sdk-for-go/sdk/azidentity"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
 func TestNewCredential(t *testing.T) {
 	options := policy.ClientOptions{}
-	// no credentials
-	creds := map[string]string{}
-	tokenCredential, _ := NewCredential(creds, options)
-
-	var scopes []string
-	scopes = append(scopes, "https://management.core.windows.net//.default")
 
-	ctx, _ := context.WithTimeout(context.Background(), time.Second*2)
-	_, err := tokenCredential.GetToken(ctx, policy.TokenRequestOptions{Scopes: scopes})
+	// invalid client secret credential (missing tenant ID)
+	creds := map[string]string{
+		CredentialKeyClientID:     "clientid",
+		CredentialKeyClientSecret: "secret",
+	}
+	_, err := NewCredential(creds, options)
 	require.NotNil(t, err)
 
-	// config credential
+	// valid client secret credential
 	creds = map[string]string{
 		CredentialKeyTenantID:     "tenantid",
 		CredentialKeyClientID:     "clientid",
 		CredentialKeyClientSecret: "secret",
 	}
-	_, err = NewCredential(creds, options)
+	tokenCredential, err := NewCredential(creds, options)
 	require.Nil(t, err)
+	assert.IsType(t, &azidentity.ClientSecretCredential{}, tokenCredential)
+
+	// client certificate credential
+	certData, err := readCertData()
+	require.Nil(t, err)
+	creds = map[string]string{
+		CredentialKeyTenantID:          "tenantid",
+		CredentialKeyClientID:          "clientid",
+		CredentialKeyClientCertificate: certData,
+	}
+	tokenCredential, err = NewCredential(creds, options)
+	require.Nil(t, err)
+	assert.IsType(t, &azidentity.ClientCertificateCredential{}, tokenCredential)
+
+	// workload identity credential
+	os.Setenv(CredentialKeyTenantID, "tenantid")
+	os.Setenv(CredentialKeyClientID, "clientid")
+	os.Setenv("AZURE_FEDERATED_TOKEN_FILE", "/tmp/token")
+	creds = map[string]string{}
+	tokenCredential, err = NewCredential(creds, options)
+	require.Nil(t, err)
+	assert.IsType(t, &azidentity.WorkloadIdentityCredential{}, tokenCredential)
+	os.Clearenv()
+
+	// managed identity credential
+	creds = map[string]string{}
+	tokenCredential, err = NewCredential(creds, options)
+	require.Nil(t, err)
+	assert.IsType(t, &azidentity.ManagedIdentityCredential{}, tokenCredential)
 }
 
 func Test_newConfigCredential(t *testing.T) {
@@ -77,10 +104,12 @@ func Test_newConfigCredential(t *testing.T) {
 	require.True(t, ok)
 
 	// client certificate
+	certData, err := readCertData()
+	require.Nil(t, err)
 	creds = map[string]string{
-		CredentialKeyTenantID:              "clientid",
-		CredentialKeyClientID:              "clientid",
-		CredentialKeyClientCertificatePath: "testdata/certificate.pem",
+		CredentialKeyTenantID:          "clientid",
+		CredentialKeyClientID:          "clientid",
+		CredentialKeyClientCertificate: certData,
 	}
 	credential, err = newConfigCredential(creds, options)
 	require.Nil(t, err)
@@ -101,3 +130,11 @@ func Test_newConfigCredential(t *testing.T) {
 	_, ok = credential.(*azidentity.UsernamePasswordCredential)
 	require.True(t, ok)
 }
+
+func readCertData() (string, error) {
+	data, err := os.ReadFile("testdata/certificate.pem")
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}