feat(cli): support env var UNCLOUD_DAEMON_VERSION to specify daemon version for "uc machine add/init" (#409)

cmd/uc/machine/add.go

@@ -47,9 +47,12 @@ Connection methods:
   [ssh://]user@host   - Use system 'ssh' command with full SSH config support (default, no prefix required)
   ssh+go://user@host  - Use Go's built-in SSH library`,
 		Args: cobra.ExactArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		PreRunE: func(cmd *cobra.Command, args []string) error {
 			cli.BindEnvToFlag(cmd, "yes", "UNCLOUD_AUTO_CONFIRM")
-
+			cli.BindEnvToFlag(cmd, "version", "UNCLOUD_DAEMON_VERSION")
+			return nil
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
 
 			// Determine connection mode and strip scheme.
@@ -97,7 +100,7 @@ Connection methods:
 	)
 	cmd.Flags().StringVar(
 		&opts.version, "version", "latest",
-		"Version of the Uncloud daemon to install on the machine.",
+		"Version of the Uncloud daemon to install on the machine. [$UNCLOUD_DAEMON_VERSION]",
 	)
 	cmd.Flags().StringSliceVar(
 		&opts.wgEndpoints, "wg-endpoint", nil,

cmd/uc/machine/flags_test.go

@@ -0,0 +1,72 @@
+package machine
+
+import (
+	"testing"
+
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// runVersionFlagEnvTest builds the given command for each case, stubs out RunE so only flag
+// parsing and PreRunE run (no SSH calls), and asserts the resolved --version flag value.
+// Note: cannot use t.Parallel() because subtests use t.Setenv().
+func runVersionFlagEnvTest(t *testing.T, newCommand func() *cobra.Command) {
+	t.Helper()
+
+	tests := []struct {
+		name string
+		args []string
+		env  string
+		want string
+	}{
+		{
+			name: "env var sets version when flag not passed",
+			args: []string{"root@localhost"},
+			env:  "v1.2.3",
+			want: "v1.2.3",
+		},
+		{
+			name: "explicit flag wins over env var",
+			args: []string{"root@localhost", "--version", "v9.9.9"},
+			env:  "v1.2.3",
+			want: "v9.9.9",
+		},
+		{
+			name: "defaults to latest when neither flag nor env var set",
+			args: []string{"root@localhost"},
+			want: "latest",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.env != "" {
+				t.Setenv("UNCLOUD_DAEMON_VERSION", tt.env)
+			}
+
+			cmd := newCommand()
+			cmd.RunE = func(*cobra.Command, []string) error {
+				return nil
+			}
+			cmd.SetArgs(tt.args)
+			require.NoError(t, cmd.Execute())
+
+			version, err := cmd.Flags().GetString("version")
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, version)
+		})
+	}
+}
+
+// TestInitCommandVersionFlagEnvVar verifies that the UNCLOUD_DAEMON_VERSION environment variable
+// is bound to the --version flag of 'machine init', and that an explicit flag wins.
+func TestInitCommandVersionFlagEnvVar(t *testing.T) {
+	runVersionFlagEnvTest(t, NewInitCommand)
+}
+
+// TestAddCommandVersionFlagEnvVar verifies that the UNCLOUD_DAEMON_VERSION environment variable
+// is bound to the --version flag of 'machine add', and that an explicit flag wins.
+func TestAddCommandVersionFlagEnvVar(t *testing.T) {
+	runVersionFlagEnvTest(t, NewAddCommand)
+}

cmd/uc/machine/init.go

@@ -65,9 +65,12 @@ Connection methods:
   uc machine init root@<your-server-ip> --no-caddy --no-dns`,
 		// TODO: support initialising a cluster on the local machine.
 		Args: cobra.MaximumNArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		PreRunE: func(cmd *cobra.Command, args []string) error {
 			cli.BindEnvToFlag(cmd, "yes", "UNCLOUD_AUTO_CONFIRM")
-
+			cli.BindEnvToFlag(cmd, "version", "UNCLOUD_DAEMON_VERSION")
+			return nil
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
 			uncli := cmd.Context().Value("cli").(*cli.CLI)
 
 			var remoteMachine *cli.RemoteMachine
@@ -135,7 +138,7 @@ Connection methods:
 	)
 	cmd.Flags().StringVar(
 		&opts.version, "version", "latest",
-		"Version of the Uncloud daemon to install on the machine.",
+		"Version of the Uncloud daemon to install on the machine. [$UNCLOUD_DAEMON_VERSION]",
 	)
 	cmd.Flags().StringSliceVar(
 		&opts.wgEndpoints, "wg-endpoint", nil,