feat: support disabling remote log uploads

Updates tailscale/tailscale#13174

- adds a new switch to the settings page for
  enabling/disabling remote log uploads

- calls the `Disable` function from the `logtail`
  package during init when the setting is turn off

ref: https://pkg.go.dev/tailscale.com/logtail#Disable

Signed-off-by: Michael Nahkies <michael@nahkies.co.nz>

Author: mnahkies

android/src/main/java/com/tailscale/ipn/App.kt

@@ -272,6 +272,9 @@ class App : UninitializedApp(), libtailscale.AppContext, ViewModelStoreOwner {
   override fun isChromeOS(): Boolean {
     return packageManager.hasSystemFeature("android.hardware.type.pc")
   }
+  override fun isClientLoggingEnabled(): Boolean {
+    return getIsClientLoggingEnabled()
+  }
   override fun getInterfacesAsString(): String {
     val interfaces: ArrayList<NetworkInterface> =
         java.util.Collections.list(NetworkInterface.getNetworkInterfaces())
@@ -351,6 +354,7 @@ open class UninitializedApp : Application() {
     // the VPN (i.e. we're logged in and machine is authorized).
     private const val ABLE_TO_START_VPN_KEY = "ableToStartVPN"
     private const val DISALLOWED_APPS_KEY = "disallowedApps"
+    private const val IS_CLIENT_LOGGING_ENABLED_KEY = "isClientLoggingEnabled"
     // File for shared preferences that are not encrypted.
     private const val UNENCRYPTED_PREFERENCES = "unencrypted"
     private lateinit var appInstance: UninitializedApp
@@ -504,6 +508,12 @@ open class UninitializedApp : Application() {
     }
     return builder.build()
   }
+  fun getIsClientLoggingEnabled(): Boolean {
+    return getUnencryptedPrefs().getBoolean(IS_CLIENT_LOGGING_ENABLED_KEY, true)
+  }
+  fun updateIsClientLoggingEnabled(value: Boolean) {
+    getUnencryptedPrefs().edit().putBoolean(IS_CLIENT_LOGGING_ENABLED_KEY, value).apply()
+  }
   fun updateUserDisallowedPackageNames(packageNames: List<String>) {
     if (packageNames.any { it.isEmpty() }) {
       TSLog.e(TAG, "updateUserDisallowedPackageNames called with empty packageName(s)")

android/src/main/java/com/tailscale/ipn/ui/view/SettingsView.kt

@@ -58,6 +58,7 @@ fun SettingsView(
   val isVPNPrepared by appViewModel.vpnPrepared.collectAsState()
   val showTailnetLock by MDMSettings.manageTailnetLock.flow.collectAsState()
   val useTailscaleSubnets by MDMSettings.useTailscaleSubnets.flow.collectAsState()
+  val isClientRemoteLoggingEnabled by viewModel.isClientRemoteLoggingEnabled.collectAsState()
 
   Scaffold(
       topBar = {
@@ -106,6 +107,16 @@ fun SettingsView(
             Lists.ItemDivider()
             Setting.Text(R.string.subnet_routing, onClick = settingsNav.onNavigateToSubnetRouting)
           }
+
+          Lists.ItemDivider()
+          Setting.Switch(
+            R.string.client_remote_logging_enabled,
+            subtitle = stringResource(R.string.client_remote_logging_enabled_subtitle),
+            isOn = isClientRemoteLoggingEnabled,
+            onToggle = {
+              viewModel.toggleIsClientRemoteLoggingEnabled()
+            })
+
           if (!AndroidTVUtil.isAndroidTV()) {
             Lists.ItemDivider()
             Setting.Text(R.string.permissions, onClick = settingsNav.onNavigateToPermissions)
@@ -175,6 +186,7 @@ object Setting {
   fun Switch(
       titleRes: Int = 0,
       title: String? = null,
+      subtitle: String? = null,
       isOn: Boolean,
       enabled: Boolean = true,
       onToggle: (Boolean) -> Unit = {}
@@ -187,6 +199,15 @@ object Setting {
               style = MaterialTheme.typography.bodyMedium,
           )
         },
+        supportingContent =
+            subtitle?.let {
+                {
+                    Text(
+                        it,
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant)
+                }
+            },
         trailingContent = {
           TintedSwitch(checked = isOn, onCheckedChange = onToggle, enabled = enabled)
         })

android/src/main/java/com/tailscale/ipn/ui/viewModel/SettingsViewModel.kt

@@ -4,6 +4,7 @@
 package com.tailscale.ipn.ui.viewModel
 
 import androidx.lifecycle.viewModelScope
+import com.tailscale.ipn.App
 import com.tailscale.ipn.ui.localapi.Client
 import com.tailscale.ipn.ui.notifier.Notifier
 import com.tailscale.ipn.ui.util.LoadingIndicator
@@ -34,8 +35,11 @@ class SettingsViewModel : IpnViewModel() {
   val tailNetLockEnabled: StateFlow<Boolean?> = MutableStateFlow(null)
   // True if tailscaleDNS is enabled. nil if not yet known.
   val corpDNSEnabled: StateFlow<Boolean?> = MutableStateFlow(null)
+  val isClientRemoteLoggingEnabled: StateFlow<Boolean> = MutableStateFlow(true)
 
   init {
+    isClientRemoteLoggingEnabled.set(App.get().isClientLoggingEnabled())
+
     viewModelScope.launch {
       Notifier.netmap.collect { netmap -> isAdmin.set(netmap?.SelfNode?.isAdmin ?: false) }
     }
@@ -52,4 +56,9 @@ class SettingsViewModel : IpnViewModel() {
       }
     }
   }
+
+  fun toggleIsClientRemoteLoggingEnabled() {
+    isClientRemoteLoggingEnabled.set(!isClientRemoteLoggingEnabled.value)
+    App.get().updateIsClientLoggingEnabled(isClientRemoteLoggingEnabled.value)
+  }
 }

android/src/main/res/values/strings.xml

@@ -346,6 +346,8 @@
     <string name="run_as_subnet_router">Run as subnet router</string>
     <string name="use_tailscale_subnets_subtitle">Route traffic according to your network\'s rules. Some networks require this to access IP addresses that don\'t start with 100.x.y.z.</string>
     <string name="subnet_routing">Subnet routing</string>
+    <string name="client_remote_logging_enabled">Remote client logging</string>
+    <string name="client_remote_logging_enabled_subtitle">Equivalent to --no-logs-no-support on Linux.\nChanges require restarting the app to take effect.</string>
     <string name="specifies_a_device_name_to_be_used_instead_of_the_automatic_default">Specifies a device name to be used instead of the automatic default.</string>
     <string name="hostname">Hostname</string>
     <string name="failed_to_save">Failed to save</string>

libtailscale/backend.go

@@ -288,7 +288,7 @@ func (a *App) newBackend(dataDir string, appCtx AppContext, store *stateStore,
 		log.Printf("netmon.New: %w", err)
 	}
 	b.netMon = netMon
-	b.setupLogs(dataDir, logID, logf, sys.HealthTracker())
+	b.setupLogs(dataDir, logID, logf, sys.HealthTracker(), a.isClientLoggingEnabled())
 	dialer := new(tsdial.Dialer)
 	vf := &VPNFacade{
 		SetBoth:           b.setCfg,

libtailscale/interfaces.go

@@ -48,6 +48,9 @@ type AppContext interface {
 	// IsChromeOS reports whether we're on a ChromeOS device.
 	IsChromeOS() (bool, error)
 
+	// IsClientLoggingEnabled reports whether the user has enabled remote client logging.
+	IsClientLoggingEnabled() (bool, error)
+
 	// GetInterfacesAsString gets a string representation of all network
 	// interfaces.
 	GetInterfacesAsString() (string, error)

libtailscale/tailscale.go

@@ -94,8 +94,16 @@ func (a *App) isChromeOS() bool {
 	return isChromeOS
 }
 
+func (a *App) isClientLoggingEnabled() bool {
+	isClientLoggingEnabled, err := a.appCtx.IsClientLoggingEnabled()
+	if err != nil {
+		panic(err)
+	}
+	return isClientLoggingEnabled
+}
+
 // SetupLogs sets up remote logging.
-func (b *backend) setupLogs(logDir string, logID logid.PrivateID, logf logger.Logf, health *health.Tracker) {
+func (b *backend) setupLogs(logDir string, logID logid.PrivateID, logf logger.Logf, health *health.Tracker, enableUpload bool) {
 	if b.netMon == nil {
 		panic("netMon must be created prior to SetupLogs")
 	}
@@ -125,6 +133,11 @@ func (b *backend) setupLogs(logDir string, logID logid.PrivateID, logf logger.Lo
 
 	b.logger = logtail.NewLogger(logcfg, logf)
 
+	if !enableUpload {
+		log.Printf("disabling remote log upload")
+		logtail.Disable()
+	}
+
 	log.SetFlags(0)
 	log.SetOutput(b.logger)