Add errors listing to libpod

Signed-off-by: Matthew Heon <mheon@redhat.com>

libpod/container.go

@@ -1,20 +1,15 @@
 package libpod
 
 import (
-	"fmt"
 	"sync"
 
 	"github.com/containers/storage"
 	"github.com/docker/docker/pkg/stringid"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
 	"github.com/ulule/deepcopier"
 )
 
-var (
-	// ErrNotImplemented indicates that functionality is not yet implemented
-	errNotImplemented = fmt.Errorf("NOT IMPLEMENTED")
-)
-
 // Container is a single OCI container
 type Container struct {
 	id   string
@@ -60,7 +55,7 @@ func (c *Container) Spec() *spec.Spec {
 // Make a new container
 func newContainer(rspec *spec.Spec) (*Container, error) {
 	if rspec == nil {
-		return nil, fmt.Errorf("must provide a valid spec to construct container")
+		return nil, errors.Wrapf(ErrInvalidArg, "must provide a valid runtime spec to create container")
 	}
 
 	ctr := new(Container)
@@ -75,52 +70,52 @@ func newContainer(rspec *spec.Spec) (*Container, error) {
 
 // Create creates a container in the OCI runtime
 func (c *Container) Create() error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Start starts a container
 func (c *Container) Start() error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Stop stops a container
 func (c *Container) Stop() error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Kill sends a signal to a container
 func (c *Container) Kill(signal uint) error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Exec starts a new process inside the container
 // Returns fully qualified URL of streaming server for executed process
 func (c *Container) Exec(cmd []string, tty bool, stdin bool) (string, error) {
-	return "", errNotImplemented
+	return "", ErrNotImplemented
 }
 
 // Attach attaches to a container
 // Returns fully qualified URL of streaming server for the container
 func (c *Container) Attach(stdin, tty bool) (string, error) {
-	return "", errNotImplemented
+	return "", ErrNotImplemented
 }
 
 // Mount mounts a container's filesystem on the host
 // The path where the container has been mounted is returned
 func (c *Container) Mount() (string, error) {
-	return "", errNotImplemented
+	return "", ErrNotImplemented
 }
 
 // Status gets a container's status
 // TODO this should return relevant information about container state
 func (c *Container) Status() error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Export exports a container's root filesystem as a tar archive
 // The archive will be saved as a file at the given path
 func (c *Container) Export(path string) error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Commit commits the changes between a container and its image, creating a new
@@ -130,5 +125,5 @@ func (c *Container) Export(path string) error {
 // a new base image will be created from the contents of the container's
 // filesystem
 func (c *Container) Commit() (*storage.Image, error) {
-	return nil, errNotImplemented
+	return nil, ErrNotImplemented
 }

libpod/errors.go

@@ -0,0 +1,53 @@
+package libpod
+
+import (
+	"errors"
+)
+
+var (
+	// ErrNoSuchCtr indicates the requested container does not exist
+	ErrNoSuchCtr = errors.New("no such container")
+	// ErrNoSuchPod indicates the requested pod does not exist
+	ErrNoSuchPod = errors.New("no such pod")
+	// ErrNoSuchImage indicates the requested image does not exist
+	ErrNoSuchImage = errors.New("no such image")
+
+	// ErrCtrExists indicates a container with the same name or ID already
+	// exists
+	ErrCtrExists = errors.New("container already exists")
+	// ErrPodExists indicates a pod with the same name or ID already exists
+	ErrPodExists = errors.New("pod already exists")
+	// ErrImageExists indicated an image with the same ID already exists
+	ErrImageExists = errors.New("image already exists")
+
+	// ErrRuntimeFinalized indicates that the runtime has already been
+	// created and cannot be modified
+	ErrRuntimeFinalized = errors.New("runtime has been finalized")
+	// ErrCtrFinalized indicates that the container has already been created
+	// and cannot be modified
+	ErrCtrFinalized = errors.New("container has been finalized")
+	// ErrPodFinalized indicates that the pod has already been created and
+	// cannot be modified
+	ErrPodFinalized = errors.New("pod has been finalized")
+
+	// ErrInvalidArg indicates that an invalid argument was passed
+	ErrInvalidArg = errors.New("invalid argument")
+
+	// ErrRuntimeStopped indicates that the runtime has already been shut
+	// down and no further operations can be performed on it
+	ErrRuntimeStopped = errors.New("runtime has already been stopped")
+	// ErrCtrStopped indicates that the requested container is not running
+	// and the requested operation cannot be performed until it is started
+	ErrCtrStopped = errors.New("container is stopped")
+
+	// ErrCtrRemoved indicates that the container has already been removed
+	// and no further operations can be performed on it
+	ErrCtrRemoved = errors.New("container has already been removed")
+	// ErrPodRemoved indicates that the pod has already been removed and no
+	// further operations can be performed on it
+	ErrPodRemoved = errors.New("pod has already been removed")
+
+	// ErrNotImplemented indicates that the requested functionality is not
+	// yet present
+	ErrNotImplemented = errors.New("not yet implemented")
+)

libpod/image.go

@@ -353,10 +353,10 @@ func (r *Runtime) GetImageRef(image string) (types.Image, error) {
 // output. Multiple filters are handled by ANDing their output, so only images
 // matching all filters are included
 func (r *Runtime) GetImages(filter ...ImageFilter) ([]*storage.Image, error) {
-	return nil, errNotImplemented
+	return nil, ErrNotImplemented
 }
 
 // ImportImage imports an OCI format image archive into storage as an image
 func (r *Runtime) ImportImage(path string) (*storage.Image, error) {
-	return nil, errNotImplemented
+	return nil, ErrNotImplemented
 }

libpod/options.go

@@ -9,9 +9,7 @@ import (
 )
 
 var (
-	errRuntimeFinalized = fmt.Errorf("runtime has already been finalized")
+	ctrNotImplemented = func(c *Container) error {
-	errCtrFinalized     = fmt.Errorf("container has already been finalized")
-	ctrNotImplemented   = func(c *Container) error {
 		return fmt.Errorf("NOT IMPLEMENTED")
 	}
 )
@@ -39,7 +37,7 @@ const (
 func WithStorageConfig(config storage.StoreOptions) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.StorageConfig.RunRoot = config.RunRoot
@@ -65,7 +63,7 @@ func WithStorageConfig(config storage.StoreOptions) RuntimeOption {
 func WithImageConfig(defaultTransport string, insecureRegistries, registries []string) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.ImageDefaultTransport = defaultTransport
@@ -87,7 +85,7 @@ func WithImageConfig(defaultTransport string, insecureRegistries, registries []s
 func WithSignaturePolicy(path string) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.SignaturePolicyPath = path
@@ -100,7 +98,7 @@ func WithSignaturePolicy(path string) RuntimeOption {
 func WithOCIRuntime(runtimePath string) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.RuntimePath = runtimePath
@@ -114,7 +112,7 @@ func WithOCIRuntime(runtimePath string) RuntimeOption {
 func WithConmonPath(path string) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.ConmonPath = path
@@ -127,7 +125,7 @@ func WithConmonPath(path string) RuntimeOption {
 func WithConmonEnv(environment []string) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.ConmonEnvVars = make([]string, len(environment))
@@ -142,7 +140,7 @@ func WithConmonEnv(environment []string) RuntimeOption {
 func WithCgroupManager(manager string) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.CgroupManager = manager
@@ -155,7 +153,7 @@ func WithCgroupManager(manager string) RuntimeOption {
 func WithSELinux() RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.SelinuxEnabled = true
@@ -169,7 +167,7 @@ func WithSELinux() RuntimeOption {
 func WithPidsLimit(limit int64) RuntimeOption {
 	return func(rt *Runtime) error {
 		if rt.valid {
-			return errRuntimeFinalized
+			return ErrRuntimeFinalized
 		}
 
 		rt.config.PidsLimit = limit
@@ -206,7 +204,7 @@ func WithSharedNamespaces(from *Container, namespaces map[string]string) CtrCrea
 func (r *Runtime) WithPod(pod *Pod) CtrCreateOption {
 	return func(ctr *Container) error {
 		if !ctr.valid {
-			return errCtrFinalized
+			return ErrCtrFinalized
 		}
 
 		if ctr.pod != nil {
@@ -217,7 +215,7 @@ func (r *Runtime) WithPod(pod *Pod) CtrCreateOption {
 		if err != nil {
 			return errors.Wrapf(err, "error searching state for pod %s", pod.ID())
 		} else if !exists {
-			return fmt.Errorf("pod with id %s not found in state")
+			return errors.Wrapf(ErrNoSuchPod, "pod %s cannot be found in state", pod.ID())
 		}
 
 		if err := pod.addContainer(ctr); err != nil {
@@ -244,7 +242,7 @@ func WithAnnotations(annotations map[string]string) CtrCreateOption {
 func WithName(name string) CtrCreateOption {
 	return func(ctr *Container) error {
 		if !ctr.valid {
-			return errCtrFinalized
+			return ErrCtrFinalized
 		}
 
 		ctr.name = name
@@ -264,7 +262,7 @@ func WithStopSignal(signal uint) CtrCreateOption {
 func WithPodName(name string) PodCreateOption {
 	return func(pod *Pod) error {
 		if pod.valid {
-			return fmt.Errorf("pod already finalized")
+			return ErrPodFinalized
 		}
 
 		pod.name = name

libpod/pod.go

@@ -1,10 +1,10 @@
 package libpod
 
 import (
-	"fmt"
 	"sync"
 
 	"github.com/docker/docker/pkg/stringid"
+	"github.com/pkg/errors"
 )
 
 // Pod represents a group of containers that may share namespaces
@@ -47,11 +47,11 @@ func (p *Pod) addContainer(ctr *Container) error {
 	defer p.lock.Unlock()
 
 	if !p.valid {
-		return fmt.Errorf("pod has already been removed")
+		return ErrPodRemoved
 	}
 
 	if _, ok := p.containers[ctr.id]; ok {
-		return fmt.Errorf("container with id %s already exists in pod %s", ctr.id, p.id)
+		return errors.Wrapf(ErrCtrExists, "container with ID %s already exists in pod %s", ctr.id, p.id)
 	}
 
 	p.containers[ctr.id] = ctr
@@ -66,11 +66,11 @@ func (p *Pod) removeContainer(ctr *Container) error {
 	defer p.lock.Unlock()
 
 	if !p.valid {
-		return fmt.Errorf("pod has already been removed")
+		return ErrPodRemoved
 	}
 
 	if _, ok := p.containers[ctr.id]; !ok {
-		return fmt.Errorf("container with id %s does not exist in pod %s", ctr.id, p.id)
+		return errors.Wrapf(ErrNoSuchCtr, "no container with id %s in pod %s", ctr.id, p.id)
 	}
 
 	delete(p.containers, ctr.id)
@@ -80,17 +80,17 @@ func (p *Pod) removeContainer(ctr *Container) error {
 
 // Start starts all containers within a pod that are not already running
 func (p *Pod) Start() error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Stop stops all containers within a pod that are not already stopped
 func (p *Pod) Stop() error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // Kill sends a signal to all running containers within a pod
 func (p *Pod) Kill(signal uint) error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // GetContainers retrieves the containers in the pod
@@ -99,7 +99,7 @@ func (p *Pod) GetContainers() ([]*Container, error) {
 	defer p.lock.RUnlock()
 
 	if !p.valid {
-		return nil, fmt.Errorf("pod has already been removed")
+		return nil, ErrPodRemoved
 	}
 
 	ctrs := make([]*Container, 0, len(p.containers))
@@ -113,5 +113,5 @@ func (p *Pod) GetContainers() ([]*Container, error) {
 // Status gets the status of all containers in the pod
 // TODO This should return a summary of the states of all containers in the pod
 func (p *Pod) Status() error {
-	return errNotImplemented
+	return ErrNotImplemented
 }

libpod/runtime.go

@@ -1,7 +1,6 @@
 package libpod
 
 import (
-	"fmt"
 	"sync"
 
 	"github.com/containers/image/types"
@@ -124,7 +123,7 @@ func (r *Runtime) Shutdown(force bool) error {
 	defer r.lock.Unlock()
 
 	if !r.valid {
-		return fmt.Errorf("runtime has already been shut down")
+		return ErrRuntimeStopped
 	}
 
 	r.valid = false
@@ -150,7 +149,7 @@ func (r *Runtime) NewContainer(spec *spec.Spec, options ...CtrCreateOption) (*Co
 	defer r.lock.Unlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	ctr, err := newContainer(spec)
@@ -187,7 +186,7 @@ func (r *Runtime) NewContainer(spec *spec.Spec, options ...CtrCreateOption) (*Co
 // If force is specified, the container will be stopped first
 // Otherwise, RemoveContainer will return an error if the container is running
 func (r *Runtime) RemoveContainer(c *Container, force bool) error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // GetContainer retrieves a container by its ID
@@ -196,7 +195,7 @@ func (r *Runtime) GetContainer(id string) (*Container, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	return r.state.GetContainer(id)
@@ -208,7 +207,7 @@ func (r *Runtime) HasContainer(id string) (bool, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return false, fmt.Errorf("runtime has already been shut down")
+		return false, ErrRuntimeStopped
 	}
 
 	return r.state.HasContainer(id)
@@ -221,7 +220,7 @@ func (r *Runtime) LookupContainer(idOrName string) (*Container, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	return r.state.LookupContainer(idOrName)
@@ -236,7 +235,7 @@ func (r *Runtime) Containers(filters ...ContainerFilter) ([]*Container, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	ctrs, err := r.state.GetAllContainers()
@@ -277,7 +276,7 @@ func (r *Runtime) NewPod(options ...PodCreateOption) (*Pod, error) {
 	defer r.lock.Unlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	pod, err := newPod()
@@ -297,7 +296,7 @@ func (r *Runtime) NewPod(options ...PodCreateOption) (*Pod, error) {
 		return nil, errors.Wrapf(err, "error adding pod to state")
 	}
 
-	return nil, errNotImplemented
+	return nil, ErrNotImplemented
 }
 
 // RemovePod removes a pod and all containers in it
@@ -305,7 +304,7 @@ func (r *Runtime) NewPod(options ...PodCreateOption) (*Pod, error) {
 // Otherwise, RemovePod will return an error if any container in the pod is running
 // Remove acts atomically, removing all containers or no containers
 func (r *Runtime) RemovePod(p *Pod, force bool) error {
-	return errNotImplemented
+	return ErrNotImplemented
 }
 
 // GetPod retrieves a pod by its ID
@@ -314,7 +313,7 @@ func (r *Runtime) GetPod(id string) (*Pod, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	return r.state.GetPod(id)
@@ -326,7 +325,7 @@ func (r *Runtime) HasPod(id string) (bool, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return false, fmt.Errorf("runtime has already been shut down")
+		return false, ErrRuntimeStopped
 	}
 
 	return r.state.HasPod(id)
@@ -339,7 +338,7 @@ func (r *Runtime) LookupPod(idOrName string) (*Pod, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	return r.state.LookupPod(idOrName)
@@ -354,7 +353,7 @@ func (r *Runtime) Pods(filters ...PodFilter) ([]*Pod, error) {
 	defer r.lock.RUnlock()
 
 	if !r.valid {
-		return nil, fmt.Errorf("runtime has already been shut down")
+		return nil, ErrRuntimeStopped
 	}
 
 	pods, err := r.state.GetAllPods()