Move io.go into cio package

Signed-off-by: Daniel Nephin <dnephin@gmail.com>
2017-11-17 14:18:30 -05:00
parent bc063f263c
commit 298dabc6c2
13 changed files with 77 additions and 69 deletions
--- a/cio/io.go
+++ b/cio/io.go
@@ -0,0 +1,196 @@
+package cio
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"sync"
+)
+
+// Config holds the io configurations.
+type Config struct {
+	// Terminal is true if one has been allocated
+	Terminal bool
+	// Stdin path
+	Stdin string
+	// Stdout path
+	Stdout string
+	// Stderr path
+	Stderr string
+}
+
+// IO holds the io information for a task or process
+type IO interface {
+	// Config returns the IO configuration.
+	Config() Config
+	// Cancel aborts all current io operations
+	Cancel()
+	// Wait blocks until all io copy operations have completed
+	Wait()
+	// Close cleans up all open io resources
+	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)
+
+// Attach allows callers to reattach to running tasks
+//
+// There should only be one reader for a task's IO set
+// because fifo's can only be read from one reader or the output
+// will be sent only to the first reads
+type Attach func(*FIFOSet) (IO, error)
+
+// NewIO returns an Creation that will provide IO sets without a terminal
+func NewIO(stdin io.Reader, stdout, stderr io.Writer) Creation {
+	return NewIOWithTerminal(stdin, stdout, stderr, false)
+}
+
+// NewIOWithTerminal creates a new io set with the provied 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) {
+		paths, err := NewFifos(id)
+		if err != nil {
+			return nil, err
+		}
+		defer func() {
+			if err != nil && paths.Dir != "" {
+				os.RemoveAll(paths.Dir)
+			}
+		}()
+		cfg := Config{
+			Terminal: terminal,
+			Stdout:   paths.Out,
+			Stderr:   paths.Err,
+			Stdin:    paths.In,
+		}
+		i := &cio{config: cfg}
+		set := &ioSet{
+			in:  stdin,
+			out: stdout,
+			err: stderr,
+		}
+		closer, err := copyIO(paths, set, cfg.Terminal)
+		if err != nil {
+			return nil, err
+		}
+		i.closer = closer
+		return i, nil
+	}
+}
+
+// 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(paths *FIFOSet) (IO, error) {
+		if paths == nil {
+			return nil, fmt.Errorf("cannot attach to existing fifos")
+		}
+		cfg := Config{
+			Terminal: paths.Terminal,
+			Stdout:   paths.Out,
+			Stderr:   paths.Err,
+			Stdin:    paths.In,
+		}
+		i := &cio{config: cfg}
+		set := &ioSet{
+			in:  stdin,
+			out: stdout,
+			err: stderr,
+		}
+		closer, err := copyIO(paths, set, cfg.Terminal)
+		if err != nil {
+			return nil, err
+		}
+		i.closer = closer
+		return i, nil
+	}
+}
+
+// Stdio returns an IO set to be used for a task
+// that outputs the container's IO as the current processes Stdio
+func Stdio(id string) (IO, error) {
+	return NewIO(os.Stdin, os.Stdout, os.Stderr)(id)
+}
+
+// StdioTerminal will setup the IO for the task to use a terminal
+func StdioTerminal(id string) (IO, error) {
+	return NewIOWithTerminal(os.Stdin, os.Stdout, os.Stderr, true)(id)
+}
+
+// NullIO redirects the container's IO into /dev/null
+func NullIO(id string) (IO, error) {
+	return &cio{}, nil
+}
+
+// FIFOSet is a set of fifos for use with tasks
+type FIFOSet struct {
+	// Dir is the directory holding the task fifos
+	Dir string
+	// In, Out, and Err fifo paths
+	In, Out, Err string
+	// Terminal returns true if a terminal is being used for the task
+	Terminal bool
+}
+
+type ioSet struct {
+	in       io.Reader
+	out, err io.Writer
+}
+
+type wgCloser struct {
+	wg     *sync.WaitGroup
+	dir    string
+	set    []io.Closer
+	cancel context.CancelFunc
+}
+
+func (g *wgCloser) Wait() {
+	g.wg.Wait()
+}
+
+func (g *wgCloser) Close() error {
+	for _, f := range g.set {
+		f.Close()
+	}
+	if g.dir != "" {
+		return os.RemoveAll(g.dir)
+	}
+	return nil
+}
+
+func (g *wgCloser) Cancel() {
+	g.cancel()
+}