Add testing for linux factory Load

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

container.go

@@ -9,30 +9,30 @@ type ContainerInfo interface {
 
 	// Returns the current run state of the container.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
-	// SystemError - System error.
-	RunState() (*RunState, Error)
+	// Systemerror - System error.
+	RunState() (*RunState, error)
 
 	// Returns the current config of the container.
 	Config() *Config
 
 	// Returns the PIDs inside this container. The PIDs are in the namespace of the calling process.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
-	// SystemError - System error.
+	// Systemerror - System error.
 	//
 	// Some of the returned PIDs may no longer refer to processes in the Container, unless
 	// the Container state is PAUSED in which case every PID in the slice is valid.
-	Processes() ([]int, Error)
+	Processes() ([]int, error)
 
 	// Returns statistics for the container.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
-	// SystemError - System error.
-	Stats() (*ContainerStats, Error)
+	// Systemerror - System error.
+	Stats() (*ContainerStats, error)
 }
 
 // A libcontainer container object.
@@ -45,60 +45,60 @@ type Container interface {
 
 	// Start a process inside the container. Returns the PID of the new process (in the caller process's namespace) and a channel that will return the exit status of the process whenever it dies.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
 	// ConfigInvalid - config is invalid,
 	// ContainerPaused - Container is paused,
-	// SystemError - System error.
-	StartProcess(config *ProcessConfig) (pid int, err Error)
+	// Systemerror - System error.
+	StartProcess(config *ProcessConfig) (pid int, err error)
 
 	// Destroys the container after killing all running processes.
 	//
 	// Any event registrations are removed before the container is destroyed.
 	// No error is returned if the container is already destroyed.
 	//
-	// Errors:
-	// SystemError - System error.
-	Destroy() Error
+	// errors:
+	// Systemerror - System error.
+	Destroy() error
 
 	// If the Container state is RUNNING or PAUSING, sets the Container state to PAUSING and pauses
 	// the execution of any user processes. Asynchronously, when the container finished being paused the
 	// state is changed to PAUSED.
 	// If the Container state is PAUSED, do nothing.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
-	// SystemError - System error.
-	Pause() Error
+	// Systemerror - System error.
+	Pause() error
 
 	// If the Container state is PAUSED, resumes the execution of any user processes in the
 	// Container before setting the Container state to RUNNING.
 	// If the Container state is RUNNING, do nothing.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
-	// SystemError - System error.
-	Resume() Error
+	// Systemerror - System error.
+	Resume() error
 
 	// Signal sends the specified signal to a process owned by the container.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
 	// ContainerPaused - Container is paused,
-	// SystemError - System error.
-	Signal(pid, signal int) Error
+	// Systemerror - System error.
+	Signal(pid, signal int) error
 
 	// Wait waits for the init process of the conatiner to die and returns it's exit status.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
-	// SystemError - System error.
-	Wait() (exitStatus int, err Error)
+	// Systemerror - System error.
+	Wait() (exitStatus int, err error)
 
 	// WaitProcess waits on a process owned by the container.
 	//
-	// Errors:
+	// errors:
 	// ContainerDestroyed - Container no longer exists,
-	// SystemError - System error.
-	WaitProcess(pid int) (exitStatus int, err Error)
+	// Systemerror - System error.
+	WaitProcess(pid int) (exitStatus int, err error)
 }

error.go

@@ -1,5 +1,7 @@
 package libcontainer
 
+import "io"
+
 // API error code type.
 type ErrorCode int
 
@@ -10,7 +12,7 @@ const (
 	InvalidIdFormat
 
 	// Container errors
-	ContainerDestroyed
+	ContainerNotExists
 	ContainerPaused
 
 	// Common errors
@@ -24,14 +26,14 @@ func (c ErrorCode) String() string {
 		return "Id already in use"
 	case InvalidIdFormat:
 		return "Invalid format"
-	case ContainerDestroyed:
-		return "Container destroyed"
 	case ContainerPaused:
 		return "Container paused"
 	case ConfigInvalid:
 		return "Invalid configuration"
 	case SystemError:
-		return "System Error"
+		return "System error"
+	case ContainerNotExists:
+		return "Container does not exist"
 	default:
 		return "Unknown error"
 	}
@@ -44,7 +46,7 @@ type Error interface {
 	// Returns a verbose string including the error message
 	// and a representation of the stack trace suitable for
 	// printing.
-	Detail() string
+	Detail(w io.Writer) error
 
 	// Returns the error code for this error.
 	Code() ErrorCode

error_test.go

@@ -0,0 +1,20 @@
+package libcontainer
+
+import "testing"
+
+func TestErrorCode(t *testing.T) {
+	codes := map[ErrorCode]string{
+		IdInUse:            "Id already in use",
+		InvalidIdFormat:    "Invalid format",
+		ContainerPaused:    "Container paused",
+		ConfigInvalid:      "Invalid configuration",
+		SystemError:        "System error",
+		ContainerNotExists: "Container does not exist",
+	}
+
+	for code, expected := range codes {
+		if actual := code.String(); actual != expected {
+			t.Fatalf("expected string %q but received %q", expected, actual)
+		}
+	}
+}

factory.go

@@ -10,21 +10,21 @@ type Factory interface {
 	//
 	// Returns the new container with a running process.
 	//
-	// Errors:
+	// errors:
 	// IdInUse - id is already in use by a container
 	// InvalidIdFormat - id has incorrect format
 	// ConfigInvalid - config is invalid
-	// SystemError - System error
+	// Systemerror - System error
 	//
 	// On error, any partially created container parts are cleaned up (the operation is atomic).
-	Create(id string, config *Config) (Container, Error)
+	Create(id string, config *Config) (Container, error)
 
 	// Load takes an ID for an existing container and returns the container information
 	// from the state.  This presents a read only view of the container.
 	//
-	// Errors:
+	// errors:
 	// Path does not exist
 	// Container is stopped
 	// System error
-	Load(id string) (ContainerInfo, Error)
+	Load(id string) (ContainerInfo, error)
 }

generic_error.go

@@ -1,46 +1,48 @@
 package libcontainer
 
 import (
-	"bytes"
 	"fmt"
-	"runtime"
+	"io"
+	"text/template"
 	"time"
+
+	"github.com/docker/libcontainer/stacktrace"
 )
 
-var newLine = []byte("\n")
+var errorTemplate = template.Must(template.New("error").Parse(`Timestamp: {{.Timestamp}}
+Code: {{.ECode}}
+Message: {{.Err.Error}}
+Frames:{{range $i, $frame := .Stack.Frames}}
+---
+{{$i}}: {{$frame.Function}}
+Package: {{$frame.Package}}
+File: {{$frame.File}}{{end}}
+`))
 
 func newGenericError(err error, c ErrorCode) Error {
 	return &GenericError{
-		timestamp: time.Now(),
-		err:       err,
-		code:      c,
-		stack:     captureStackTrace(2),
+		Timestamp: time.Now(),
+		Err:       err,
+		ECode:     c,
+		Stack:     stacktrace.Capture(2),
 	}
 }
 
-func captureStackTrace(skip int) string {
-	buf := make([]byte, 4096)
-	buf = buf[:runtime.Stack(buf, true)]
-
-	lines := bytes.Split(buf, newLine)
-	return string(bytes.Join(lines[skip:], newLine))
-}
-
 type GenericError struct {
-	timestamp time.Time
-	code      ErrorCode
-	err       error
-	stack     string
+	Timestamp time.Time
+	ECode     ErrorCode
+	Err       error
+	Stack     stacktrace.Stacktrace
 }
 
 func (e *GenericError) Error() string {
-	return fmt.Sprintf("[%d] %s: %s", e.code, e.code, e.err)
+	return fmt.Sprintf("[%d] %s: %s", e.ECode, e.ECode, e.Err)
 }
 
 func (e *GenericError) Code() ErrorCode {
-	return e.code
+	return e.ECode
 }
 
-func (e *GenericError) Detail() string {
-	return fmt.Sprintf("[%d] %s\n%s", e.code, e.err, e.stack)
+func (e *GenericError) Detail(w io.Writer) error {
+	return errorTemplate.Execute(w, e)
 }

generic_error_test.go

@@ -0,0 +1,14 @@
+package libcontainer
+
+import (
+	"fmt"
+	"io/ioutil"
+	"testing"
+)
+
+func TestErrorDetail(t *testing.T) {
+	err := newGenericError(fmt.Errorf("test error"), SystemError)
+	if derr := err.Detail(ioutil.Discard); derr != nil {
+		t.Fatal(derr)
+	}
+}

linux_container.go

@@ -23,11 +23,11 @@ func (c *linuxContainer) Config() *Config {
 	return c.config
 }
 
-func (c *linuxContainer) RunState() (*RunState, Error) {
+func (c *linuxContainer) RunState() (*RunState, error) {
 	panic("not implemented")
 }
 
-func (c *linuxContainer) Processes() ([]int, Error) {
+func (c *linuxContainer) Processes() ([]int, error) {
 	var (
 		err  error
 		pids []int
@@ -44,7 +44,7 @@ func (c *linuxContainer) Processes() ([]int, Error) {
 	return pids, nil
 }
 
-func (c *linuxContainer) Stats() (*ContainerStats, Error) {
+func (c *linuxContainer) Stats() (*ContainerStats, error) {
 	var (
 		err   error
 		stats = &ContainerStats{}

linux_factory.go

@@ -14,7 +14,7 @@ const (
 )
 
 // New returns a linux based container factory based in the root directory.
-func New(root string) (Factory, Error) {
+func New(root string) (Factory, error) {
 	if err := os.MkdirAll(root, 0700); err != nil {
 		return nil, newGenericError(err, SystemError)
 	}
@@ -30,11 +30,11 @@ type linuxFactory struct {
 	root string
 }
 
-func (l *linuxFactory) Create(id string, config *Config) (Container, Error) {
+func (l *linuxFactory) Create(id string, config *Config) (Container, error) {
 	panic("not implemented")
 }
 
-func (l *linuxFactory) Load(id string) (ContainerInfo, Error) {
+func (l *linuxFactory) Load(id string) (ContainerInfo, error) {
 	containerRoot := filepath.Join(l.root, id)
 	config, err := l.loadContainerConfig(containerRoot)
 	if err != nil {
@@ -54,11 +54,11 @@ func (l *linuxFactory) Load(id string) (ContainerInfo, Error) {
 	}, nil
 }
 
-func (l *linuxFactory) loadContainerConfig(root string) (*Config, Error) {
+func (l *linuxFactory) loadContainerConfig(root string) (*Config, error) {
 	f, err := os.Open(filepath.Join(root, configFilename))
 	if err != nil {
 		if os.IsNotExist(err) {
-			return nil, newGenericError(err, ContainerDestroyed)
+			return nil, newGenericError(err, ContainerNotExists)
 		}
 		return nil, newGenericError(err, SystemError)
 	}
@@ -71,11 +71,11 @@ func (l *linuxFactory) loadContainerConfig(root string) (*Config, Error) {
 	return config, nil
 }
 
-func (l *linuxFactory) loadContainerState(root string) (*State, Error) {
+func (l *linuxFactory) loadContainerState(root string) (*State, error) {
 	f, err := os.Open(filepath.Join(root, stateFilename))
 	if err != nil {
 		if os.IsNotExist(err) {
-			return nil, newGenericError(err, ContainerDestroyed)
+			return nil, newGenericError(err, ContainerNotExists)
 		}
 		return nil, newGenericError(err, SystemError)
 	}

linux_factory_test.go

@@ -0,0 +1,144 @@
+// +build linux
+
+package libcontainer
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func newTestRoot() (string, error) {
+	dir, err := ioutil.TempDir("", "libcontainer")
+	if err != nil {
+		return "", err
+	}
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		return "", err
+	}
+	return dir, nil
+}
+
+func TestFactoryNew(t *testing.T) {
+	root, rerr := newTestRoot()
+	if rerr != nil {
+		t.Fatal(rerr)
+	}
+	defer os.RemoveAll(root)
+
+	factory, err := New(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if factory == nil {
+		t.Fatal("factory should not be nil")
+	}
+
+	lfactory, ok := factory.(*linuxFactory)
+	if !ok {
+		t.Fatal("expected linux factory returned on linux based systems")
+	}
+
+	if lfactory.root != root {
+		t.Fatalf("expected factory root to be %q but received %q", root, lfactory.root)
+	}
+}
+
+func TestFactoryLoadNotExists(t *testing.T) {
+	root, rerr := newTestRoot()
+	if rerr != nil {
+		t.Fatal(rerr)
+	}
+	defer os.RemoveAll(root)
+
+	factory, err := New(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = factory.Load("nocontainer")
+	if err == nil {
+		t.Fatal("expected nil error loading non-existing container")
+	}
+
+	lerr, ok := err.(Error)
+	if !ok {
+		t.Fatal("expected libcontainer error type")
+	}
+	if lerr.Code() != ContainerNotExists {
+		t.Fatalf("expected error code %s but received %s", ContainerNotExists, lerr.Code())
+	}
+}
+
+func TestFactoryLoadContainer(t *testing.T) {
+	root, err := newTestRoot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(root)
+
+	// setup default container config and state for mocking
+	var (
+		id             = "1"
+		expectedConfig = &Config{
+			RootFs: "/mycontainer/root",
+		}
+		expectedState = &State{
+			InitPid: 1024,
+		}
+	)
+
+	if err := os.Mkdir(filepath.Join(root, id), 0700); err != nil {
+		t.Fatal(err)
+	}
+	if err := marshal(filepath.Join(root, id, configFilename), expectedConfig); err != nil {
+		t.Fatal(err)
+	}
+	if err := marshal(filepath.Join(root, id, stateFilename), expectedState); err != nil {
+		t.Fatal(err)
+	}
+
+	factory, err := New(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	container, err := factory.Load(id)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if container.ID() != id {
+		t.Fatalf("expected container id %q but received %q", id, container.ID())
+	}
+
+	config := container.Config()
+	if config == nil {
+		t.Fatal("expected non nil container config")
+	}
+
+	if config.RootFs != expectedConfig.RootFs {
+		t.Fatalf("expected rootfs %q but received %q", expectedConfig.RootFs, config.RootFs)
+	}
+
+	lcontainer, ok := container.(*linuxContainer)
+	if !ok {
+		t.Fatal("expected linux container on linux based systems")
+	}
+
+	if lcontainer.state.InitPid != expectedState.InitPid {
+		t.Fatalf("expected init pid %d but received %d", expectedState.InitPid, lcontainer.state.InitPid)
+	}
+}
+
+func marshal(path string, v interface{}) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	return json.NewEncoder(f).Encode(v)
+}