feat(cloud): support plaintext file credential store on systems without an OS keychain

› Tenant ID:  fails on headless Linux (containers, VMs, CI) because
no D-Bus Secret Service is available and the keychain resolver refuses
to construct. Add an explicit --insecure-file-store flag that enables
dry's plaintext file fallback (~/.config/safedep/creds.json, mode 0600)
for writing.

Reading is fallback-enabled unconditionally in the credential resolver
chain, logout and setup info, so stored file credentials resolve with
no extra flags and logout can always clear them. On systems with a
working keychain the file provider is never constructed.

analyzer/malysis_factory.go

@@ -15,7 +15,9 @@ type credentialsResolver func() (*cloud.Credentials, func() error, error)
 // the unauthenticated community analyzer if the API rejects the credentials.
 // When no credentials are available, it returns the community analyzer.
 func NewMalysisAnalyzer(config MalysisQueryAnalyzerConfig) (PackageVersionAnalyzer, error) {
-	return newMalysisAnalyzer(config, cloudauth.ResolveCredentials)
+	return newMalysisAnalyzer(config, func() (*cloud.Credentials, func() error, error) {
+		return cloudauth.ResolveCredentials()
+	})
 }
 
 func newMalysisAnalyzer(config MalysisQueryAnalyzerConfig,

cmd/cloud/login.go

@@ -9,7 +9,10 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var loginFromEnv bool
+var (
+	loginFromEnv           bool
+	loginInsecureFileStore bool
+)
 
 func newLoginCommand() *cobra.Command {
 	cmd := &cobra.Command{
@@ -20,6 +23,8 @@ func newLoginCommand() *cobra.Command {
 
 	cmd.Flags().BoolVar(&loginFromEnv, "from-env", false,
 		"Read credentials from SAFEDEP_API_KEY and SAFEDEP_TENANT_ID environment variables")
+	cmd.Flags().BoolVar(&loginInsecureFileStore, "insecure-file-store", false,
+		"Store credentials in a plaintext file when no OS keychain is available (headless Linux, containers)")
 
 	return cmd
 }
@@ -89,13 +94,18 @@ func runLogin(cmd *cobra.Command, args []string) error {
 		}
 	}
 
-	store, err := cloud.NewKeychainCredentialStore()
+	var opts []cloud.KeychainOption
+	if loginInsecureFileStore {
+		opts = append(opts, cloud.WithInsecureFileFallback())
+	}
+
+	store, err := cloud.NewKeychainCredentialStore(opts...)
 	if err != nil {
 		ui.ErrorExit(usefulerror.NewUsefulError().
 			Wrap(err).
 			WithCode(errcodes.Lifecycle).
 			WithHumanError("Failed to initialize credential store").
-			WithHelp("Your system may not support secure credential storage"))
+			WithHelp("No OS keychain is available. Re-run with --insecure-file-store to use plaintext file storage, or set SAFEDEP_API_KEY and SAFEDEP_TENANT_ID environment variables"))
 	}
 	defer func() {
 		if err := store.Close(); err != nil {
@@ -111,6 +121,10 @@ func runLogin(cmd *cobra.Command, args []string) error {
 			WithHelp("Your system may not support secure credential storage"))
 	}
 
-	ui.Successf("Credentials saved securely")
+	if loginInsecureFileStore {
+		ui.Successf("Credentials saved")
+	} else {
+		ui.Successf("Credentials saved securely")
+	}
 	return nil
 }

cmd/cloud/logout.go

@@ -18,7 +18,7 @@ func newLogoutCommand() *cobra.Command {
 }
 
 func runLogout(cmd *cobra.Command, args []string) error {
-	store, err := cloud.NewKeychainCredentialStore()
+	store, err := cloud.NewKeychainCredentialStore(cloud.WithInsecureFileFallback())
 	if err != nil {
 		ui.ErrorExit(usefulerror.NewUsefulError().
 			Wrap(err).

cmd/setup/info.go

@@ -227,7 +227,7 @@ func describeCloudCredentials() string {
 }
 
 func tryResolveKeychainCredentials() (string, bool) {
-	resolver, err := cloud.NewKeychainCredentialResolver(cloud.CredentialTypeAPIKey)
+	resolver, err := cloud.NewKeychainCredentialResolver(cloud.CredentialTypeAPIKey, cloud.WithInsecureFileFallback())
 	if err != nil {
 		log.Debugf("keychain credential resolver unavailable: %v", err)
 		return "", false

internal/cloudauth/resolver.go

@@ -16,13 +16,20 @@ import (
 // credentials and a close function that releases keychain resources. The
 // close function is always non-nil and safe to call regardless of the error.
 //
+// The insecure file fallback is always enabled for reading so credentials
+// stored via `pmg cloud login --insecure-file-store` on systems without an
+// OS keychain (headless Linux, containers) resolve without extra flags. On
+// systems with a working keychain the file provider is never constructed.
+//
 // An error is returned when no credentials are available, which callers can
 // use to decide whether authenticated cloud features should be enabled.
-func ResolveCredentials() (*cloud.Credentials, func() error, error) {
+func ResolveCredentials(opts ...cloud.KeychainOption) (*cloud.Credentials, func() error, error) {
 	var resolvers []cloud.CredentialResolver
 	var keychainResolver cloud.CloseableCredentialResolver
 
-	keychainResolver, err := cloud.NewKeychainCredentialResolver(cloud.CredentialTypeAPIKey)
+	keychainOpts := append([]cloud.KeychainOption{cloud.WithInsecureFileFallback()}, opts...)
+
+	keychainResolver, err := cloud.NewKeychainCredentialResolver(cloud.CredentialTypeAPIKey, keychainOpts...)
 	if err != nil {
 		log.Debugf("Keychain credential resolver not available, skipping: %v", err)
 	} else {

internal/cloudauth/resolver_test.go

@@ -0,0 +1,71 @@
+package cloudauth
+
+import (
+	"testing"
+
+	"github.com/safedep/dry/cloud"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func testKeychainOptions(t *testing.T) []cloud.KeychainOption {
+	t.Helper()
+	return []cloud.KeychainOption{
+		cloud.WithAppName("safedep-test-" + t.Name()),
+		cloud.WithInsecureFileFallbackPath(t.TempDir() + "/creds.json"),
+	}
+}
+
+func TestResolveCredentialsFromKeychainStore(t *testing.T) {
+	t.Setenv("SAFEDEP_API_KEY", "")
+	t.Setenv("SAFEDEP_TENANT_ID", "")
+
+	opts := testKeychainOptions(t)
+
+	store, err := cloud.NewKeychainCredentialStore(opts...)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		require.NoError(t, store.Clear())
+		require.NoError(t, store.Close())
+	})
+
+	require.NoError(t, store.SaveAPIKeyCredential("sk-test-key", "tenant-123"))
+
+	creds, closeFn, err := ResolveCredentials(opts...)
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, closeFn()) })
+
+	apiKey, err := creds.GetAPIKey()
+	require.NoError(t, err)
+	assert.Equal(t, "sk-test-key", apiKey)
+
+	tenant, err := creds.GetTenantDomain()
+	require.NoError(t, err)
+	assert.Equal(t, "tenant-123", tenant)
+}
+
+func TestResolveCredentialsFallsBackToEnv(t *testing.T) {
+	t.Setenv("SAFEDEP_API_KEY", "env-key")
+	t.Setenv("SAFEDEP_TENANT_ID", "env-tenant")
+
+	creds, closeFn, err := ResolveCredentials(testKeychainOptions(t)...)
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, closeFn()) })
+
+	apiKey, err := creds.GetAPIKey()
+	require.NoError(t, err)
+	assert.Equal(t, "env-key", apiKey)
+
+	tenant, err := creds.GetTenantDomain()
+	require.NoError(t, err)
+	assert.Equal(t, "env-tenant", tenant)
+}
+
+func TestResolveCredentialsNoCredentials(t *testing.T) {
+	t.Setenv("SAFEDEP_API_KEY", "")
+	t.Setenv("SAFEDEP_TENANT_ID", "")
+
+	_, closeFn, err := ResolveCredentials(testKeychainOptions(t)...)
+	require.Error(t, err)
+	require.NoError(t, closeFn())
+}