Resources: Update interface to support errors

This was an early interface mistake I made and is now corrected.
We'll plumb in checking the error state of Init() and running Validate()
later on.

resources/exec.go

@@ -71,24 +71,24 @@ func NewExecRes(name, cmd, shell string, timeout int, watchcmd, watchshell, ifcm
 }
 
 // Init runs some startup code for this resource.
-func (obj *ExecRes) Init() {
+func (obj *ExecRes) Init() error {
 	obj.BaseRes.kind = "Exec"
-	obj.BaseRes.Init() // call base init, b/c we're overriding
+	return obj.BaseRes.Init() // call base init, b/c we're overriding
 }
 
-// validate if the params passed in are valid data
+// Validate if the params passed in are valid data.
 // FIXME: where should this get called ?
-func (obj *ExecRes) Validate() bool {
+func (obj *ExecRes) Validate() error {
 	if obj.Cmd == "" { // this is the only thing that is really required
-		return false
+		return fmt.Errorf("Command can't be empty!")
 	}
 
 	// if we have a watch command, then we don't poll with the if command!
 	if obj.WatchCmd != "" && obj.PollInt > 0 {
-		return false
+		return fmt.Errorf("Don't poll when we have a watch command.")
 	}
 
-	return true
+	return nil
 }
 
 // wraps the scanner output in a channel

resources/file.go

@@ -84,7 +84,7 @@ func NewFileRes(name, path, dirname, basename, content, source, state string, re
 }
 
 // Init runs some startup code for this resource.
-func (obj *FileRes) Init() {
+func (obj *FileRes) Init() error {
 	obj.sha256sum = ""
 	obj.watches = make(map[string]struct{})
 	if obj.Path == "" { // use the name as the path default if missing
@@ -94,7 +94,7 @@ func (obj *FileRes) Init() {
 	obj.isDir = strings.HasSuffix(obj.path, "/") // dirs have trailing slashes
 
 	obj.BaseRes.kind = "File"
-	obj.BaseRes.Init() // call base init, b/c we're overriding
+	return obj.BaseRes.Init() // call base init, b/c we're overriding
 }
 
 // GetPath returns the actual path to use for this resource. It computes this

resources/noop.go

@@ -48,15 +48,15 @@ func NewNoopRes(name string) *NoopRes {
 }
 
 // Init runs some startup code for this resource.
-func (obj *NoopRes) Init() {
+func (obj *NoopRes) Init() error {
 	obj.BaseRes.kind = "Noop"
-	obj.BaseRes.Init() // call base init, b/c we're overriding
+	return obj.BaseRes.Init() // call base init, b/c we're overriding
 }
 
 // validate if the params passed in are valid data
 // FIXME: where should this get called ?
-func (obj *NoopRes) Validate() bool {
-	return true
+func (obj *NoopRes) Validate() error {
+	return nil
 }
 
 // Watch is the primary listener for this resource and it outputs events.

resources/pkg.go

@@ -58,55 +58,52 @@ func NewPkgRes(name, state string, allowuntrusted, allownonfree, allowunsupporte
 		AllowNonFree:     allownonfree,
 		AllowUnsupported: allowunsupported,
 	}
-	obj.Init()
+	obj.Init() // XXX: on error return nil, or separate error return?
 	return obj
 }
 
 // Init runs some startup code for this resource.
-func (obj *PkgRes) Init() {
+func (obj *PkgRes) Init() error {
 	obj.BaseRes.kind = "Pkg"
-	obj.BaseRes.Init() // call base init, b/c we're overriding
+	if err := obj.BaseRes.Init(); err != nil { // call base init, b/c we're overriding
+		return err
+	}
 
 	bus := packagekit.NewBus()
 	if bus == nil {
-		log.Fatal("Can't connect to PackageKit bus.")
+		return fmt.Errorf("Can't connect to PackageKit bus.")
 	}
 	defer bus.Close()
 
 	result, err := obj.pkgMappingHelper(bus)
 	if err != nil {
-		// FIXME: return error?
-		log.Fatalf("The pkgMappingHelper failed with: %v.", err)
-		return
+		return fmt.Errorf("The pkgMappingHelper failed with: %v.", err)
 	}
 
 	data, ok := result[obj.Name] // lookup single package (init does just one)
 	// package doesn't exist, this is an error!
 	if !ok || !data.Found {
-		// FIXME: return error?
-		log.Fatalf("Can't find package named '%s'.", obj.Name)
-		return
+		return fmt.Errorf("Can't find package named '%s'.", obj.Name)
 	}
 
 	packageIDs := []string{data.PackageID} // just one for now
 	filesMap, err := bus.GetFilesByPackageID(packageIDs)
 	if err != nil {
-		// FIXME: return error?
-		log.Fatalf("Can't run GetFilesByPackageID: %v", err)
-		return
+		return fmt.Errorf("Can't run GetFilesByPackageID: %v", err)
 	}
 	if files, ok := filesMap[data.PackageID]; ok {
 		obj.fileList = util.DirifyFileList(files, false)
 	}
+	return nil
 }
 
 // Validate checks if the resource data structure was populated correctly.
-func (obj *PkgRes) Validate() bool {
+func (obj *PkgRes) Validate() error {
 	if obj.State == "" {
-		return false
+		return fmt.Errorf("State cannot be empty!")
 	}
 
-	return true
+	return nil
 }
 
 // Watch is the primary listener for this resource and it outputs events.

resources/resources.go

@@ -104,8 +104,8 @@ type Base interface {
 // Res is the minimum interface you need to implement to define a new resource.
 type Res interface {
 	Base // include everything from the Base interface
-	Init()
-	//Validate() bool    // TODO: this might one day be added
+	Init() error
+	//Validate() error    // TODO: this might one day be added
 	GetUUIDs() []ResUUID          // most resources only return one
 	Watch(chan event.Event) error // send on channel to signal process() events
 	CheckApply(bool) (bool, error)
@@ -170,8 +170,9 @@ func (obj *BaseUUID) Reversed() bool {
 }
 
 // Init initializes structures like channels if created without New constructor.
-func (obj *BaseRes) Init() {
+func (obj *BaseRes) Init() error {
 	obj.events = make(chan event.Event) // unbuffered chan size to avoid stale events
+	return nil
 }
 
 // GetName is used by all the resources to Get the name.

resources/svc.go

@@ -59,20 +59,20 @@ func NewSvcRes(name, state, startup string) *SvcRes {
 }
 
 // Init runs some startup code for this resource.
-func (obj *SvcRes) Init() {
+func (obj *SvcRes) Init() error {
 	obj.BaseRes.kind = "Svc"
-	obj.BaseRes.Init() // call base init, b/c we're overriding
+	return obj.BaseRes.Init() // call base init, b/c we're overriding
 }
 
 // Validate checks if the resource data structure was populated correctly.
-func (obj *SvcRes) Validate() bool {
+func (obj *SvcRes) Validate() error {
 	if obj.State != "running" && obj.State != "stopped" && obj.State != "" {
-		return false
+		return fmt.Errorf("State must be either `running` or `stopped` or undefined.")
 	}
 	if obj.Startup != "enabled" && obj.Startup != "disabled" && obj.Startup != "" {
-		return false
+		return fmt.Errorf("Startup must be either `enabled` or `disabled` or undefined.")
 	}
-	return true
+	return nil
 }
 
 // Watch is the primary listener for this resource and it outputs events.

resources/timer.go

@@ -54,16 +54,16 @@ func NewTimerRes(name string, interval int) *TimerRes {
 }
 
 // Init runs some startup code for this resource.
-func (obj *TimerRes) Init() {
+func (obj *TimerRes) Init() error {
 	obj.BaseRes.kind = "Timer"
-	obj.BaseRes.Init() // call base init, b/c we're overrriding
+	return obj.BaseRes.Init() // call base init, b/c we're overrriding
 }
 
 // Validate the params that are passed to TimerRes
 // Currently we are getting only an interval in seconds
 // which gets validated by go compiler
-func (obj *TimerRes) Validate() bool {
-	return true
+func (obj *TimerRes) Validate() error {
+	return nil
 }
 
 // Watch is the primary listener for this resource and it outputs events.