Address file name too long error when passing certs as literal values (#1719)

* handle long literal values for certs

* Use testify for shorter tests

---------

Co-authored-by: Julien Duchesne <[email protected]>

Author: lornest

Diff for: pkg/provider/configure_clients.go

@@ -9,6 +9,7 @@ import (
 	"net/url"
 	"os"
 	"strings"
+	"syscall"
 	"time"
 
 	onCallAPI "github.com/grafana/amixr-api-go-client"
@@ -190,7 +191,7 @@ func createTempFileIfLiteral(value string) (path string, tempFile bool, err erro
 		return "", false, nil
 	}
 
-	if _, err := os.Stat(value); errors.Is(err, os.ErrNotExist) {
+	if _, err := os.Stat(value); errors.Is(err, os.ErrNotExist) || errors.Is(err, syscall.ENAMETOOLONG) {
 		// value is not a file path, assume it's a literal
 		f, err := os.CreateTemp("", "grafana-provider-tls")
 		if err != nil {

Diff for: pkg/provider/configure_clients_test.go

@@ -0,0 +1,91 @@
+package provider
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreateTempFileIfLiteral(t *testing.T) {
+	t.Run("Test with empty string value returns empty and does not create temp file", func(t *testing.T) {
+		path, tempFile, err := createTempFileIfLiteral("")
+		require.NoError(t, err)
+		require.False(t, tempFile, "Expected temp file to not be created")
+		require.Empty(t, path)
+	})
+	t.Run("Test file path returns given path and does not create a temp file", func(t *testing.T) {
+		// Create a temporary file to simulate an existing file
+		tmp, err := os.CreateTemp(t.TempDir(), "existing-file")
+		require.NoError(t, err)
+
+		path, tempFile, err := createTempFileIfLiteral(tmp.Name())
+		require.NoError(t, err)
+		require.False(t, tempFile, "Expected temp file to not be created")
+		require.Equal(t, tmp.Name(), path)
+	})
+
+	t.Run("Test with short literal creates temp file and path", func(t *testing.T) {
+		caCert := "certTest"
+
+		path, tempFile, err := createTempFileIfLiteral(caCert)
+		require.NoError(t, err)
+		require.True(t, tempFile, "Expected temp file to be created")
+		require.NotEmpty(t, path)
+
+		// Validate the file was created and has the correct content
+		content, err := os.ReadFile(path)
+		require.NoError(t, err)
+		require.Equal(t, caCert, string(content))
+
+		// Clean up the temporary file
+		require.NoError(t, os.Remove(path))
+	})
+
+	t.Run("Test with a certificate literal creates temp file and path", func(t *testing.T) {
+		caCert := ` -----BEGIN CERTIFICATE-----
+	MIIDXTCCAkWgAwIBAgIJAMW9UJtz1MoNMA0GCSqGSIb3DQEBCwUAMEUxCzAJBgNV
+	BAYTAkFVMRMwEQYDVQQIDApxdWVlbnNsYW5kMRAwDgYDVQQHDAdicmlzYmFuZTEN
+	MAsGA1UECgwEVGVzdDAeFw0xODA2MTAwNzU1NDJaFw0xOTA2MTAwNzU1NDJaMEUx
+	CzAJBgNVBAYTAkFVMRMwEQYDVQQIDApxdWVlbnNsYW5kMRAwDgYDVQQHDAdicmlz
+	YmFuZTENMAsGA1UECgwEVGVzdDCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoC
+	ggEBAK1lpt+lPZJbG7yMYYWzjk8FwGbM3vlUJlC2aQHJ18T2aTtsOaZC1deKtwGR
+	qBZMyel3hG0XayZmFQO2DAnOScgn4j+jPEFLWswg+U4MgH80+PA4wHzm+E0v68qD
+	S+cA9If1D2I0gtT6jKPm3WYwZ/r0GUn8/JjgiIhCZGfXArH39V2D2KNhJ3W0b7T6
+	isfbsHvSKWs/49q8w5J/yN8GOh/n/rThBfhM3FQ2eDdVR1QfvvX5KT69aXhtJlD9
+	Z5H8z9DnD8BZxBrzE5hEO74KK13CvAFeKbVp7KvXf6NOy4W31lUd6lmzZ+lR+IxO
+	NHElgJoaJ2F2y4XcFXY1cQFhKjkCAwEAAaNQME4wHQYDVR0OBBYEFLPkkSMxs/PR
+	1E7VwDhRu5DTHwrNMB8GA1UdIwQYMBaAFLPkkSMxs/PR1E7VwDhRu5DTHwrNMAwG
+	A1UdEwQFMAMBAf8wDQYJKoZIhvcNAQELBQADggEBAK1lpt+lPZJbG7yMYYWzjk8F
+	wGbM3vlUJlC2aQHJ18T2aTtsOaZC1deKtwGRqBZMyel3hG0XayZmFQO2DAnOScgn
+	4j+jPEFLWswg+U4MgH80+PA4wHzm+E0v68qDS+cA9If1D2I0gtT6jKPm3WYwZ/r0
+	GUn8/JjgiIhCZGfXArH39V2D2KNhJ3W0b7T6isfbsHvSKWs/49q8w5J/yN8GOh/n
+	/rThBfhM3FQ2eDdVR1QfvvX5KT69aXhtJlD9Z5H8z9DnD8BZxBrzE5hEO74KK13C
+	vAFeKbVp7KvXf6NOy4W31lUd6lmzZ+lR+IxONHElgJoaJ2F2y4XcFXY1cQFhKjkC
+	AwEAAaNQME4wHQYDVR0OBBYEFLPkkSMxs/PR1E7VwDhRu5DTHwrNMB8GA1UdIwQY
+	MBaAFLPkkSMxs/PR1E7VwDhRu5DTHwrNMAwGA1UdEwQFMAMBAf8wDQYJKoZIhvcN
+	AQELBQADggEBAK1lpt+lPZJbG7yMYYWzjk8FwGbM3vlUJlC2aQHJ18T2aTtsOaZC
+	1deKtwGRqBZMyel3hG0XayZmFQO2DAnOScgn4j+jPEFLWswg+U4MgH80+PA4wHzm
+	+E0v68qDS+cA9If1D2I0gtT6jKPm3WYwZ/r0GUn8/JjgiIhCZGfXArH39V2D2KNh
+	J3W0b7T6isfbsHvSKWs/49q8w5J/yN8GOh/n/rThBfhM3FQ2eDdVR1QfvvX5KT69
+	aXhtJlD9Z5H8z9DnD8BZxBrzE5hEO74KK13CvAFeKbVp7KvXf6NOy4W31lUd6lmz
+	Z+lR+IxONHElgJoaJ2F2y4XcFXY1cQFhKjkCAwEAAaNQME4wHQYDVR0OBBYEFLPk
+	kSMxs/PR1E7VwDhRu5DTHwrNMB8GA1UdIwQYMBaAFLPkkSMxs/PR1E7VwDhRu5DT
+	HwrNMAwGA1UdEwQFMAMBAf8wDQYJKoZIhvcNAQELBQADggEBAK1lpt+lPZJbG7yM
+	YYWzjk8FwGbM3vlUJl=
+    -----END CERTIFICATE-----`
+
+		path, tempFile, err := createTempFileIfLiteral(caCert)
+		require.NoError(t, err)
+		require.True(t, tempFile, "Expected temp file to be created")
+		require.NotEmpty(t, path)
+
+		// Check if the file exists and has the correct content
+		content, err := os.ReadFile(path)
+		require.NoError(t, err)
+		require.Equal(t, caCert, string(content))
+
+		// Clean up the temporary file
+		require.NoError(t, os.Remove(path))
+	})
+}