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Refactor cio.DirectIO
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New code duplication
Better re-use from consumers of the cio package

TODO: io_windows.go

Signed-off-by: Daniel Nephin <dnephin@gmail.com>
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@dnephin
dnephin committed Dec 8, 2017
1 parent f79ec5b commit 3146019
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Showing 4 changed files with 164 additions and 188 deletions.
122 changes: 48 additions & 74 deletions cio/io.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,38 +33,6 @@ type IO interface {
Close() error
}

// cio is a basic container IO implementation.
type cio struct {
config Config

closer *wgCloser
}

func (c *cio) Config() Config {
return c.config
}

func (c *cio) Cancel() {
if c.closer == nil {
return
}
c.closer.Cancel()
}

func (c *cio) Wait() {
if c.closer == nil {
return
}
c.closer.Wait()
}

func (c *cio) Close() error {
if c.closer == nil {
return nil
}
return c.closer.Close()
}

// Creation creates new IO sets for a task
type Creation func(id string) (IO, error)

Expand Down Expand Up @@ -100,45 +68,26 @@ func NewIO(stdin io.Reader, stdout, stderr io.Writer) Creation {

// NewIOWithTerminal creates a new io set with the provided io.Reader/Writers for use with a terminal
func NewIOWithTerminal(stdin io.Reader, stdout, stderr io.Writer, terminal bool) Creation {
return func(id string) (_ IO, err error) {
fifos, err := newFIFOSetTempDir(id)
return func(id string) (IO, error) {
fifos, err := newFIFOSetInTempDir(id)
if err != nil {
return nil, err
}
defer func() {
if err != nil {
fifos.Close()
}
}()
cfg := fifos.Config
cfg.Terminal = terminal
i := &cio{config: cfg}
set := &ioSet{
in: stdin,
out: stdout,
err: stderr,
}
closer, err := copyIO(fifos, set, cfg.Terminal)
i.closer = closer
return i, err

fifos.Terminal = terminal
set := &ioSet{in: stdin, out: stdout, err: stderr}
return copyIO(fifos, set)
}
}

// WithAttach attaches the existing io for a task to the provided io.Reader/Writers
func WithAttach(stdin io.Reader, stdout, stderr io.Writer) Attach {
return func(fifos *FIFOSet) (IO, error) {
if fifos == nil {
return nil, fmt.Errorf("cannot attach to existing fifos")
}
i := &cio{config: fifos.Config}
set := &ioSet{
in: stdin,
out: stdout,
err: stderr,
return nil, fmt.Errorf("cannot attach, missing fifos")
}
closer, err := copyIO(fifos, set, fifos.Terminal)
i.closer = closer
return i, err
set := &ioSet{in: stdin, out: stdout, err: stderr}
return copyIO(fifos, set)
}
}

Expand All @@ -154,7 +103,7 @@ func StdioTerminal(id string) (IO, error) {
}

// NullIO redirects the container's IO into /dev/null
func NullIO(id string) (IO, error) {
func NullIO(_ string) (IO, error) {
return &cio{}, nil
}

Expand All @@ -163,24 +112,49 @@ type ioSet struct {
out, err io.Writer
}

type wgCloser struct {
wg *sync.WaitGroup
set []io.Closer
cancel context.CancelFunc
type pipes struct {
Stdin io.WriteCloser
Stdout io.ReadCloser
Stderr io.ReadCloser
}

func (g *wgCloser) Wait() {
g.wg.Wait()
func (p *pipes) closers() []io.Closer {
return []io.Closer{p.Stdin, p.Stdout, p.Stderr}
}

// cio is a basic container IO implementation.
type cio struct {
config Config
wg *sync.WaitGroup
closers []io.Closer
cancel context.CancelFunc
}

func (c *cio) Config() Config {
return c.config
}

func (g *wgCloser) Close() error {
// TODO: this should return all errors, not mask them
for _, f := range g.set {
f.Close()
func (c *cio) Wait() {
if c.wg != nil {
c.wg.Wait()
}
return nil
}

func (g *wgCloser) Cancel() {
g.cancel()
func (c *cio) Close() error {
var lastErr error
for _, closer := range c.closers {
if closer == nil {
continue
}
if err := closer.Close(); err != nil {
lastErr = err
}
}
return lastErr
}

func (c *cio) Cancel() {
if c.cancel != nil {
c.cancel()
}
}
168 changes: 63 additions & 105 deletions cio/io_unix.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,10 +12,11 @@ import (
"syscall"

"github.com/containerd/fifo"
"github.com/pkg/errors"
)

// newFIFOSetTempDir returns a new set of fifos for the task
func newFIFOSetTempDir(id string) (*FIFOSet, error) {
// newFIFOSetInTempDir returns a new set of fifos for the task
func newFIFOSetInTempDir(id string) (*FIFOSet, error) {
root := "/run/containerd/fifo"
if err := os.MkdirAll(root, 0700); err != nil {
return nil, err
Expand All @@ -34,142 +35,99 @@ func newFIFOSetTempDir(id string) (*FIFOSet, error) {
}, closer), nil
}

func copyIO(fifos *FIFOSet, ioset *ioSet, tty bool) (_ *wgCloser, err error) {
func copyIO(fifos *FIFOSet, ioset *ioSet) (*cio, error) {
var (
f io.ReadWriteCloser
ctx, cancel = context.WithCancel(context.Background())
wg = &sync.WaitGroup{}
)
set := []io.Closer{fifos}
defer func() {
if err != nil {
for _, f := range set {
f.Close()
}
cancel()
}
}()

if f, err = fifo.OpenFifo(ctx, fifos.Stdin, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
pipes, err := openFifos(ctx, fifos)
if err != nil {
cancel()
return nil, err
}
set = append(set, f)
go func(w io.WriteCloser) {
io.Copy(w, ioset.in)
w.Close()
}(f)

if f, err = fifo.OpenFifo(ctx, fifos.Stdout, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
return nil, err
if fifos.Stdin != "" {
go func() {
io.Copy(pipes.Stdin, ioset.in)
pipes.Stdin.Close()
}()
}
set = append(set, f)

wg.Add(1)
go func(r io.ReadCloser) {
io.Copy(ioset.out, r)
r.Close()
go func() {
io.Copy(ioset.out, pipes.Stdout)
pipes.Stdout.Close()
wg.Done()
}(f)

if f, err = fifo.OpenFifo(ctx, fifos.Stderr, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
return nil, err
}
set = append(set, f)
}()

if !tty {
if !fifos.Terminal {
wg.Add(1)
go func(r io.ReadCloser) {
io.Copy(ioset.err, r)
r.Close()
go func() {
io.Copy(ioset.err, pipes.Stderr)
pipes.Stderr.Close()
wg.Done()
}(f)
}()
}
return &wgCloser{
wg: wg,
set: set,
cancel: cancel,
return &cio{
wg: wg,
closers: append(pipes.closers(), fifos),
cancel: cancel,
}, nil
}

// NewDirectIO returns an IO implementation that exposes the pipes directly
func NewDirectIO(ctx context.Context, terminal bool) (*DirectIO, error) {
set, err := newFIFOSetTempDir("")
if err != nil {
return nil, err
}
set.Terminal = terminal
f := &DirectIO{set: set}
func openFifos(ctx context.Context, fifos *FIFOSet) (pipes, error) {
var err error
f := new(pipes)

defer func() {
if err != nil {
f.Delete()
fifos.Close()
}
}()
if f.Stdin, err = fifo.OpenFifo(ctx, set.Stdin, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
return nil, err

if fifos.Stdin != "" {
if f.Stdin, err = fifo.OpenFifo(ctx, fifos.Stdin, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
return pipes{}, errors.Wrapf(err, "failed to open stdin fifo")
}
}
if f.Stdout, err = fifo.OpenFifo(ctx, set.Stdout, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
if f.Stdout, err = fifo.OpenFifo(ctx, fifos.Stdout, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
f.Stdin.Close()
return nil, err
return pipes{}, errors.Wrapf(err, "failed to open stdout fifo")
}
if f.Stderr, err = fifo.OpenFifo(ctx, set.Stderr, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
if f.Stderr, err = fifo.OpenFifo(ctx, fifos.Stderr, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); err != nil {
f.Stdin.Close()
f.Stdout.Close()
return pipes{}, errors.Wrapf(err, "failed to open stderr fifo")
}
return pipes{}, nil
}

// NewDirectIO returns an IO implementation that exposes the IO streams as io.ReadCloser
// and io.WriteCloser. FIFOs are created in /run/containerd/fifo.
func NewDirectIO(ctx context.Context, terminal bool) (*DirectIO, error) {
fifos, err := newFIFOSetInTempDir("")
if err != nil {
return nil, err
}
return f, nil
fifos.Terminal = terminal

ctx, cancel := context.WithCancel(context.Background())
pipes, err := openFifos(ctx, fifos)
return &DirectIO{
pipes: pipes,
cio: cio{
config: fifos.Config,
closers: append(pipes.closers(), fifos),
cancel: cancel,
},
}, err
}

// DirectIO allows task IO to be handled externally by the caller
type DirectIO struct {
Stdin io.WriteCloser
Stdout io.ReadCloser
Stderr io.ReadCloser

set *FIFOSet
}

// IOCreate returns IO avaliable for use with task creation
func (f *DirectIO) IOCreate(id string) (IO, error) {
return f, nil
}

// IOAttach returns IO avaliable for use with task attachment
func (f *DirectIO) IOAttach(set *FIFOSet) (IO, error) {
return f, nil
}

// Config returns the Config
func (f *DirectIO) Config() Config {
return f.set.Config
}

// Cancel stops any IO copy operations
//
// Not applicable for DirectIO
func (f *DirectIO) Cancel() {
// nothing to cancel as all operations are handled externally
}

// Wait on any IO copy operations
//
// Not applicable for DirectIO
func (f *DirectIO) Wait() {
// nothing to wait on as all operations are handled externally
pipes
cio
}

// Close closes all open fds
func (f *DirectIO) Close() error {
err := f.Stdin.Close()
if err2 := f.Stdout.Close(); err == nil {
err = err2
}
if err2 := f.Stderr.Close(); err == nil {
err = err2
}
return err
}

// Delete removes the underlying directory containing fifos
func (f *DirectIO) Delete() error {
return f.set.Close()
}
var _ IO = &DirectIO{}
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