Add golint to test (#255)

* Add a new lint rule to the Makefile

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

* Fix linter errors

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

* Allow replacing the default apt mirror

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

supervisor/add_process.go

@@ -7,6 +7,8 @@ import (
 	"github.com/docker/containerd/specs"
 )
 
+// AddProcessTask holds everything necessary to add a process to a
+// container
 type AddProcessTask struct {
 	baseTask
 	ID            string

supervisor/checkpoint.go

@@ -4,6 +4,7 @@ package supervisor
 
 import "github.com/docker/containerd/runtime"
 
+// CreateCheckpointTask holds needed parameters to create a new checkpoint
 type CreateCheckpointTask struct {
 	baseTask
 	ID            string
@@ -19,6 +20,7 @@ func (s *Supervisor) createCheckpoint(t *CreateCheckpointTask) error {
 	return i.container.Checkpoint(*t.Checkpoint, t.CheckpointDir)
 }
 
+// DeleteCheckpointTask holds needed parameters to delete a checkpoint
 type DeleteCheckpointTask struct {
 	baseTask
 	ID            string

supervisor/create.go

@@ -7,6 +7,7 @@ import (
 	"github.com/docker/containerd/runtime"
 )
 
+// StartTask holds needed parameters to create a new container
 type StartTask struct {
 	baseTask
 	ID            string

supervisor/delete.go

@@ -7,6 +7,7 @@ import (
 	"github.com/docker/containerd/runtime"
 )
 
+// DeleteTask holds needed parameters to remove a container
 type DeleteTask struct {
 	baseTask
 	ID      string

supervisor/errors.go

@@ -3,14 +3,18 @@ package supervisor
 import "errors"
 
 var (
-	// External errors
-	ErrTaskChanNil            = errors.New("containerd: task channel is nil")
-	ErrBundleNotFound         = errors.New("containerd: bundle not found")
-	ErrContainerNotFound      = errors.New("containerd: container not found")
-	ErrContainerExists        = errors.New("containerd: container already exists")
-	ErrProcessNotFound        = errors.New("containerd: process not found for container")
+	// ErrContainerNotFound is returned when the container ID passed
+	// for a given operation is invalid
+	ErrContainerNotFound = errors.New("containerd: container not found")
+	// ErrProcessNotFound is returned when the process ID passed for
+	// a given operation is invalid
+	ErrProcessNotFound = errors.New("containerd: process not found for container")
+	// ErrUnknownContainerStatus is returned when the container status
+	// cannot be determined
 	ErrUnknownContainerStatus = errors.New("containerd: unknown container status ")
-	ErrUnknownTask            = errors.New("containerd: unknown task type")
+	// ErrUnknownTask is returned when an unknown Task type is
+	// scheduled (should never happen).
+	ErrUnknownTask = errors.New("containerd: unknown task type")
 
 	// Internal errors
 	errShutdown          = errors.New("containerd: supervisor is shutdown")

supervisor/exit.go

@@ -7,6 +7,7 @@ import (
 	"github.com/docker/containerd/runtime"
 )
 
+// ExitTask holds needed parameters to execute the exit task
 type ExitTask struct {
 	baseTask
 	Process runtime.Process
@@ -56,6 +57,7 @@ func (s *Supervisor) exit(t *ExitTask) error {
 	return nil
 }
 
+// ExecExitTask holds needed parameters to execute the exec exit task
 type ExecExitTask struct {
 	baseTask
 	ID      string

supervisor/get_containers.go

@@ -2,6 +2,8 @@ package supervisor
 
 import "github.com/docker/containerd/runtime"
 
+// GetContainersTask holds needed parameters to retrieve a list of
+// containers
 type GetContainersTask struct {
 	baseTask
 	ID         string

supervisor/machine.go

@@ -4,11 +4,14 @@ package supervisor
 
 import "github.com/cloudfoundry/gosigar"
 
+// Machine holds the current machine cpu count and ram size
 type Machine struct {
 	Cpus   int
 	Memory int64
 }
 
+// CollectMachineInformation returns information regarding the current
+// machine (e.g. CPU count, RAM amount)
 func CollectMachineInformation() (Machine, error) {
 	m := Machine{}
 	cpu := sigar.CpuList{}

supervisor/metrics.go

@@ -3,18 +3,29 @@ package supervisor
 import "github.com/rcrowley/go-metrics"
 
 var (
-	ContainerCreateTimer   = metrics.NewTimer()
-	ContainerDeleteTimer   = metrics.NewTimer()
-	ContainerStartTimer    = metrics.NewTimer()
-	ContainerStatsTimer    = metrics.NewTimer()
-	ContainersCounter      = metrics.NewCounter()
+	// ContainerCreateTimer holds the metrics timer associated with container creation
+	ContainerCreateTimer = metrics.NewTimer()
+	// ContainerDeleteTimer holds the metrics timer associated with container deletion
+	ContainerDeleteTimer = metrics.NewTimer()
+	// ContainerStartTimer holds the metrics timer associated with container start duration
+	ContainerStartTimer = metrics.NewTimer()
+	// ContainerStatsTimer holds the metrics timer associated with container stats generation
+	ContainerStatsTimer = metrics.NewTimer()
+	// ContainersCounter keeps track of the number of active containers
+	ContainersCounter = metrics.NewCounter()
+	// EventSubscriberCounter keeps track of the number of active event subscribers
 	EventSubscriberCounter = metrics.NewCounter()
-	TasksCounter           = metrics.NewCounter()
-	ExecProcessTimer       = metrics.NewTimer()
-	ExitProcessTimer       = metrics.NewTimer()
-	EpollFdCounter         = metrics.NewCounter()
+	// TasksCounter keeps track of the number of active supervisor tasks
+	TasksCounter = metrics.NewCounter()
+	// ExecProcessTimer holds the metrics timer associated with container exec
+	ExecProcessTimer = metrics.NewTimer()
+	// ExitProcessTimer holds the metrics timer associated with reporting container exit status
+	ExitProcessTimer = metrics.NewTimer()
+	// EpollFdCounter keeps trac of how many process are being monitored
+	EpollFdCounter = metrics.NewCounter()
 )
 
+// Metrics return the list of all available metrics
 func Metrics() map[string]interface{} {
 	return map[string]interface{}{
 		"container-create-time": ContainerCreateTimer,

supervisor/monitor_linux.go

@@ -9,6 +9,7 @@ import (
 	"github.com/docker/containerd/runtime"
 )
 
+// NewMonitor starts a new process monitor and returns it
 func NewMonitor() (*Monitor, error) {
 	m := &Monitor{
 		receivers: make(map[int]interface{}),
@@ -24,6 +25,7 @@ func NewMonitor() (*Monitor, error) {
 	return m, nil
 }
 
+// Monitor represents a runtime.Process monitor
 type Monitor struct {
 	m         sync.Mutex
 	receivers map[int]interface{}
@@ -32,14 +34,17 @@ type Monitor struct {
 	epollFd   int
 }
 
+// Exits returns the channel used to notify of a process exit
 func (m *Monitor) Exits() chan runtime.Process {
 	return m.exits
 }
 
+// OOMs returns the channel used to notify of a container exit due to OOM
 func (m *Monitor) OOMs() chan string {
 	return m.ooms
 }
 
+// Monitor adds a process to the list of the one being monitored
 func (m *Monitor) Monitor(p runtime.Process) error {
 	m.m.Lock()
 	defer m.m.Unlock()
@@ -56,6 +61,7 @@ func (m *Monitor) Monitor(p runtime.Process) error {
 	return nil
 }
 
+// MonitorOOM adds a container to the list of the ones monitored for OOM
 func (m *Monitor) MonitorOOM(c runtime.Container) error {
 	m.m.Lock()
 	defer m.m.Unlock()
@@ -76,6 +82,7 @@ func (m *Monitor) MonitorOOM(c runtime.Container) error {
 	return nil
 }
 
+// Close cleans up resources allocated by NewMonitor()
 func (m *Monitor) Close() error {
 	return syscall.Close(m.epollFd)
 }

supervisor/oom.go

@@ -6,6 +6,7 @@ import (
 	"github.com/Sirupsen/logrus"
 )
 
+// OOMTask holds needed parameters to report a container OOM
 type OOMTask struct {
 	baseTask
 	ID string

supervisor/signal.go

@@ -2,6 +2,7 @@ package supervisor
 
 import "os"
 
+// SignalTask holds needed parameters to signal a container
 type SignalTask struct {
 	baseTask
 	ID     string

supervisor/stats.go

@@ -6,6 +6,7 @@ import (
 	"github.com/docker/containerd/runtime"
 )
 
+// StatsTask holds needed parameters to retrieve a container statistics
 type StatsTask struct {
 	baseTask
 	ID   string

supervisor/supervisor.go

@@ -144,6 +144,7 @@ func readEventLog(s *Supervisor) error {
 	return nil
 }
 
+// Supervisor represents a container supervisor
 type Supervisor struct {
 	// stateDir is the directory on the system to store container runtime state information.
 	stateDir string
@@ -179,6 +180,7 @@ func (s *Supervisor) Close() error {
 	return nil
 }
 
+// Event represents a container event
 type Event struct {
 	ID        string    `json:"id"`
 	Type      string    `json:"type"`

supervisor/update.go

@@ -6,6 +6,7 @@ import (
 	"github.com/docker/containerd/runtime"
 )
 
+// UpdateTask holds needed parameters to update a container resource constraints
 type UpdateTask struct {
 	baseTask
 	ID        string
@@ -50,6 +51,8 @@ func (s *Supervisor) updateContainer(t *UpdateTask) error {
 	return nil
 }
 
+// UpdateProcessTask holds needed parameters to update a container
+// process terminal size or close its stdin
 type UpdateProcessTask struct {
 	baseTask
 	ID         string

supervisor/worker.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/containerd/runtime"
 )
 
+// Worker interface
 type Worker interface {
 	Start()
 }
@@ -22,6 +23,7 @@ type startTask struct {
 	StartResponse  chan StartResponse
 }
 
+// NewWorker return a new initialized worker
 func NewWorker(s *Supervisor, wg *sync.WaitGroup) Worker {
 	return &worker{
 		s:  s,
@@ -34,6 +36,7 @@ type worker struct {
 	s  *Supervisor
 }
 
+// Start runs a loop in charge of starting new containers
 func (w *worker) Start() {
 	defer w.wg.Done()
 	for t := range w.s.startTasks {