Show correct help message with adapter errors

cmd/tesla-control/main.go

@@ -16,6 +16,7 @@ import (
 	"github.com/teslamotors/vehicle-command/internal/log"
 	"github.com/teslamotors/vehicle-command/pkg/account"
 	"github.com/teslamotors/vehicle-command/pkg/cli"
+	"github.com/teslamotors/vehicle-command/pkg/connector/ble"
 	"github.com/teslamotors/vehicle-command/pkg/protocol"
 	"github.com/teslamotors/vehicle-command/pkg/vehicle"
 )
@@ -163,12 +164,10 @@ func main() {
 
 	acct, car, err := config.Connect(ctx)
 	if err != nil {
-		writeErr("Error: %s", err)
-		// Error isn't wrapped so we have to check for a substring explicitly.
-		if strings.Contains(err.Error(), "operation not permitted") {
-			// The underlying BLE package calls HCIDEVDOWN on the BLE device, presumably as a
-			// heavy-handed way of dealing with devices that are in a bad state.
-			writeErr("\nTry again after granting this application CAP_NET_ADMIN:\n\n\tsudo setcap 'cap_net_admin=eip' \"$(which %s)\"\n", os.Args[0])
+		if ble.IsAdapterError(err) {
+			writeErr("%s", ble.AdapterErrorHelpMessage(err))
+		} else {
+			writeErr("Error: %s", err)
 		}
 		return
 	}

pkg/connector/ble/ble.go

@@ -297,7 +297,7 @@ func NewConnectionToBleTarget(ctx context.Context, vin string, target *ScanResul
 		if err == nil {
 			return conn, nil
 		}
-		if !retry || strings.Contains(err.Error(), "operation not permitted") {
+		if !retry || IsAdapterError(err) {
 			return nil, err
 		}
 		log.Warning("BLE connection attempt failed: %s", err)

pkg/connector/ble/device_darwin.go

@@ -5,8 +5,18 @@ import (
 	"tinygo.org/x/bluetooth"
 )
 
+func IsAdapterError(err error) bool {
+	// TODO: Add check for Darwin
+	return false
+}
+
+func AdapterErrorHelpMessage(err error) string {
+	return err.Error()
+}
+
 func newAdapter(id string) *bluetooth.Adapter {
 	if id != "" {
+		// TODO: Add support for Darwin
 		log.Warning("BLE adapter ID is not supported on Darwin")
 	}
 

pkg/connector/ble/device_linux.go

@@ -1,9 +1,29 @@
 package ble
 
 import (
+	"strings"
+
 	"tinygo.org/x/bluetooth"
 )
 
+func IsAdapterError(err error) bool {
+	// D-Bus not found
+	if strings.Contains(err.Error(), "dbus") && strings.HasSuffix(err.Error(), "no such file or directory") {
+		return true
+	}
+	// D-Bus is running but org.bluez is not found
+	if strings.Contains(err.Error(), "The name org.bluez was not provided by any .service files") {
+		return true
+	}
+	return false
+}
+
+func AdapterErrorHelpMessage(err error) string {
+	return "Failed to initialize BLE adapter: \n\t" + err.Error() + "\n" +
+		"Make sure bluez and dbus are installed and running.\n" +
+		"If running in a container, make sure the container has access to the host's D-Bus socket. (e.g. -v /var/run/dbus:/var/run/dbus)"
+}
+
 func newAdapter(id string) *bluetooth.Adapter {
 	if id != "" {
 		return bluetooth.NewAdapter(id)

pkg/connector/ble/device_windows.go

@@ -5,8 +5,18 @@ import (
 	"tinygo.org/x/bluetooth"
 )
 
+func IsAdapterError(err error) bool {
+	// TODO: Add check for Windows
+	return false
+}
+
+func AdapterErrorHelpMessage(err error) string {
+	return err.Error()
+}
+
 func newAdapter(id string) *bluetooth.Adapter {
 	if id != "" {
+		// TODO: Add support for Windows
 		log.Warning("BLE adapter ID is not supported on Windows")
 	}