fix(agent): allow disabling Tailscale netns (#618)

internal/config/config.go

@@ -8,6 +8,7 @@ type Config struct {
 	Hostname     string
 	TSControlURL string
 	TSAuthKey    string
+	TSNetNS      bool
 	WorkDir      string
 }
 
@@ -16,6 +17,7 @@ const (
 	HostnameEnv     = "HEADPLANE_AGENT_HOSTNAME"
 	TSControlURLEnv = "HEADPLANE_AGENT_TS_SERVER"
 	TSAuthKeyEnv    = "HEADPLANE_AGENT_TS_AUTHKEY"
+	TSNetNSEnv      = "HEADPLANE_AGENT_TS_NETNS"
 	WorkDirEnv      = "HEADPLANE_AGENT_WORK_DIR"
 )
 
@@ -26,6 +28,7 @@ func Load() (*Config, error) {
 		Hostname:     os.Getenv(HostnameEnv),
 		TSControlURL: os.Getenv(TSControlURLEnv),
 		TSAuthKey:    os.Getenv(TSAuthKeyEnv),
+		TSNetNS:      os.Getenv(TSNetNSEnv) != "false",
 		WorkDir:      os.Getenv(WorkDirEnv),
 	}
 

internal/config/config_test.go

@@ -0,0 +1,44 @@
+package config
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func loadTestConfig(t *testing.T, tailscaleNetNS string) *Config {
+	t.Helper()
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+	t.Cleanup(server.Close)
+
+	t.Setenv(DebugEnv, "false")
+	t.Setenv(HostnameEnv, "headplane-agent")
+	t.Setenv(TSControlURLEnv, server.URL)
+	t.Setenv(TSAuthKeyEnv, "test-auth-key")
+	t.Setenv(TSNetNSEnv, tailscaleNetNS)
+	t.Setenv(WorkDirEnv, t.TempDir())
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() returned an error: %v", err)
+	}
+
+	return cfg
+}
+
+func TestLoadTailscaleNetNSEnabledByDefault(t *testing.T) {
+	cfg := loadTestConfig(t, "")
+	if !cfg.TSNetNS {
+		t.Fatal("TSNetNS is false, want true")
+	}
+}
+
+func TestLoadTailscaleNetNSDisabled(t *testing.T) {
+	cfg := loadTestConfig(t, "false")
+	if cfg.TSNetNS {
+		t.Fatal("TSNetNS is true, want false")
+	}
+}