Pass error instead of panic

adaptor.go

@@ -11,8 +11,8 @@ type Adaptor struct {
 
 // AdaptorInterface defines behaviour expected for a Gobot Adaptor
 type AdaptorInterface interface {
-	Finalize() bool
+	Finalize() error
-	Connect() bool
+	Connect() error
 	Port() string
 	Name() string
 	Type() string

connection.go

@@ -2,6 +2,7 @@ package gobot
 
 import (
 	"errors"
+	"fmt"
 	"log"
 )
 
@@ -37,8 +38,9 @@ func (c *connections) Start() error {
 			info = info + " on port " + connection.Port()
 		}
 		log.Println(info + "...")
-		if connection.Connect() == false {
+		err = connection.Connect()
-			err = errors.New("Could not start connection")
+		if err != nil {
+			err = errors.New(fmt.Sprintf("Could not start connection: %v", err))
 			break
 		}
 	}

device.go

@@ -2,6 +2,7 @@ package gobot
 
 import (
 	"errors"
+	"fmt"
 	"log"
 )
 
@@ -39,8 +40,9 @@ func (d *devices) Start() error {
 			info = info + " on pin " + device.Pin()
 		}
 		log.Println(info + "...")
-		if device.Start() == false {
+		err = device.Start()
-			err = errors.New("Could not start device")
+		if err != nil {
+			err = errors.New(fmt.Sprintf("Could not start device: %v", err))
 			break
 		}
 	}

driver.go

@@ -7,8 +7,8 @@ import (
 
 // DriverInterface defines Driver expected behaviour
 type DriverInterface interface {
-	Start() bool
+	Start() error
-	Halt() bool
+	Halt() error
 	Adaptor() AdaptorInterface
 	SetInterval(time.Duration)
 	Interval() time.Duration

gobot.go

@@ -56,8 +56,11 @@ func (g *Gobot) Command(name string) func(map[string]interface{}) interface{} {
 }
 
 // Start runs the main Gobot event loop
-func (g *Gobot) Start() {
+func (g *Gobot) Start() error {
-	g.robots.Start()
+	err := g.robots.Start()
+	if err != nil {
+		return err
+	}
 
 	c := make(chan os.Signal, 1)
 	g.trap(c)
@@ -69,6 +72,7 @@ func (g *Gobot) Start() {
 		r.Devices().Halt()
 		r.Connections().Finalize()
 	})
+	return nil
 }
 
 // Robots fetch all robots associated with this Gobot instance.

robot.go

@@ -1,6 +1,7 @@
 package gobot
 
 import (
+	"errors"
 	"fmt"
 	"log"
 )
@@ -33,13 +34,17 @@ func (r *robots) Len() int {
 
 // Start initialises the event loop. All robots that were added will
 // be automtically started as a result of this call.
-func (r *robots) Start() {
+func (r *robots) Start() error {
 	for _, robot := range *r {
-		robot.Start()
+		err := robot.Start()
+		if err != nil {
+			return err
+		}
 	}
+	return nil
 }
 
-// Each enumerates thru the robts and calls specified function
+// Each enumerates thru the robots and calls specified function
 func (r *robots) Each(f func(*Robot)) {
 	for _, robot := range *r {
 		f(robot)
@@ -105,18 +110,19 @@ func (r *Robot) Command(name string) func(map[string]interface{}) interface{} {
 // Start a robot instance and runs it's work function if any. You should not
 // need to manually start a robot if already part of a Gobot application as the
 // robot will be automatically started for you.
-func (r *Robot) Start() {
+func (r *Robot) Start() error {
 	log.Println("Starting Robot", r.Name, "...")
 	if err := r.Connections().Start(); err != nil {
-		panic("Could not start connections")
+		return errors.New(fmt.Sprintf("Could not start connections: %v", err))
 	}
 	if err := r.Devices().Start(); err != nil {
-		panic("Could not start devices")
+		return errors.New(fmt.Sprintf("Could not start devices %v", err))
 	}
 	if r.Work != nil {
 		log.Println("Starting work...")
 		r.Work()
 	}
+	return nil
 }
 
 // Devices retrieves all devices associated with this robot.

test_helper.go

@@ -62,9 +62,8 @@ type testDriver struct {
 	Driver
 }
 
-func (t *testDriver) Init() bool  { return true }
+func (t *testDriver) Start() error { return nil }
-func (t *testDriver) Start() bool { return true }
+func (t *testDriver) Halt() error  { return nil }
-func (t *testDriver) Halt() bool  { return true }
 
 func NewTestDriver(name string, adaptor *testAdaptor) *testDriver {
 	t := &testDriver{
@@ -94,8 +93,8 @@ type testAdaptor struct {
 	Adaptor
 }
 
-func (t *testAdaptor) Finalize() bool { return true }
+func (t *testAdaptor) Finalize() error { return nil }
-func (t *testAdaptor) Connect() bool  { return true }
+func (t *testAdaptor) Connect() error  { return nil }
 
 func NewTestAdaptor(name string) *testAdaptor {
 	return &testAdaptor{