feat(machine): add validation for machine names to accept only DNS labels

internal/machine/cluster/machine_test.go

@@ -1,8 +1,10 @@
 package cluster
 
 import (
+	"strings"
 	"testing"
 
+	"github.com/psviderski/uncloud/pkg/api"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -18,9 +20,11 @@ func TestMachineNameFromHostname(t *testing.T) {
 		{"simple", "web", "web"},
 		{"fqdn uses first label", "web-1.example.com", "web-1"},
 		{"uppercase lowercased", "Web-Server", "web-server"},
-		{"invalid chars replaced", "host_name@1", "host_name-1"},
-		{"trim surrounding hyphens", "-_host_-", "_host_"},
+		{"invalid chars replaced", "host_name@1", "host-name-1"},
+		{"trim surrounding hyphens", "-_host_-", "host"},
 		{"whitespace trimmed", "  myhost  ", "myhost"},
+		{"long hostname truncated", strings.Repeat("a", 64), strings.Repeat("a", 63)},
+		{"truncation trims trailing hyphen", strings.Repeat("a", 62) + "-b", strings.Repeat("a", 62)},
 		{"empty", "", ""},
 		{"only invalid chars", "@#", ""},
 		{"dot only", ".example.com", ""},
@@ -37,10 +41,12 @@ func TestDefaultMachineName(t *testing.T) {
 	t.Parallel()
 
 	t.Run("falls back to random", func(t *testing.T) {
-		// An empty or fully invalid hostname falls back to a random "machine-xxxx" name.
-		got, err := DefaultMachineName("***", nil)
-		require.NoError(t, err)
-		assert.Regexp(t, `^machine-[a-zA-Z0-9]{4}$`, got)
+		for _, hostname := range []string{"***", "rr", "nearest", strings.Repeat("a", 32)} {
+			got, err := DefaultMachineName(hostname, nil)
+			require.NoError(t, err)
+			assert.Regexp(t, `^machine-[a-z0-9]{4}$`, got)
+			require.NoError(t, api.ValidateMachineName(got))
+		}
 	})
 
 	tests := []struct {
@@ -49,10 +55,45 @@ func TestDefaultMachineName(t *testing.T) {
 		existing []string
 		want     string
 	}{
-		{"from hostname", "web-1.example.com", nil, "web-1"},
-		{"dedup against existing", "web", []string{"web"}, "web-1"},
-		{"dedup multiple", "web", []string{"web", "web-1"}, "web-2"},
-		{"sanitized", "My_Host", nil, "my_host"},
+		{
+			name:     "from hostname",
+			hostname: "web-1.example.com",
+			want:     "web-1",
+		},
+		{
+			name:     "dedup against existing",
+			hostname: "web",
+			existing: []string{"web"},
+			want:     "web-1",
+		},
+		{
+			name:     "dedup multiple",
+			hostname: "web",
+			existing: []string{"web", "web-1"},
+			want:     "web-2",
+		},
+		{
+			name:     "sanitized",
+			hostname: "My_Host",
+			want:     "my-host",
+		},
+		{
+			name:     "long hostname",
+			hostname: strings.Repeat("a", 64),
+			want:     strings.Repeat("a", 63),
+		},
+		{
+			name:     "dedup maximum length",
+			hostname: strings.Repeat("a", 63),
+			existing: []string{strings.Repeat("a", 63)},
+			want:     strings.Repeat("a", 61) + "-1",
+		},
+		{
+			name:     "dedup trims trailing hyphen",
+			hostname: strings.Repeat("a", 60) + "-bb",
+			existing: []string{strings.Repeat("a", 60) + "-bb"},
+			want:     strings.Repeat("a", 60) + "-1",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -60,6 +101,7 @@ func TestDefaultMachineName(t *testing.T) {
 			got, err := DefaultMachineName(tt.hostname, tt.existing)
 			require.NoError(t, err)
 			assert.Equal(t, tt.want, got)
+			require.NoError(t, api.ValidateMachineName(got))
 		})
 	}
 }