1. docker
  2. Commit d1535131d259bb8a980770d47c0865a1be4373e3
Browse code

Flush stdin from within chroot archive

This makes sure that we don't buffer in memory and that we also flush
stdin from diff as well as untar.

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

Michael Crosby authored on 2014/12/09 08:04:34
Showing 4 changed files
pkg/chrootarchive/archive.go
History View file @ d153513
... ... 
@@ -6,7 +6,6 @@ import (
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 	"flag"
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 	"fmt"
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 	"io"
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-	"io/ioutil"
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 	"os"
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 	"runtime"
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 	"strings"
... ... 
@@ -35,9 +34,7 @@ func untar() {
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 		fatal(err)
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 	}
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 	// fully consume stdin in case it is zero padded
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-	if _, err := ioutil.ReadAll(os.Stdin); err != nil {
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-		fatal(err)
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-	}
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+	flush(os.Stdin)
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 	os.Exit(0)
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 }
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pkg/chrootarchive/archive_test.go
History View file @ d153513
... ... 
@@ -83,3 +83,19 @@ func TestChrootUntarEmptyArchiveFromSlowReader(t *testing.T) {
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 		t.Fatal(err)
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 	}
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 }
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+
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+func TestChrootApplyEmptyArchiveFromSlowReader(t *testing.T) {
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+	tmpdir, err := ioutil.TempDir("", "docker-TestChrootApplyEmptyArchiveFromSlowReader")
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+	if err != nil {
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+		t.Fatal(err)
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+	}
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+	defer os.RemoveAll(tmpdir)
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+	dest := filepath.Join(tmpdir, "dest")
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+	if err := os.MkdirAll(dest, 0700); err != nil {
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+		t.Fatal(err)
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+	}
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+	stream := &slowEmptyTarReader{size: 10240, chunkSize: 1024}
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+	if err := ApplyLayer(dest, stream); err != nil {
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+		t.Fatal(err)
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+	}
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+}
pkg/chrootarchive/diff.go
History View file @ d153513
... ... 
@@ -32,6 +32,7 @@ func applyLayer() {
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 		fatal(err)
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 	}
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 	os.RemoveAll(tmpDir)
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+	flush(os.Stdin)
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 	os.Exit(0)
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 }
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pkg/chrootarchive/init.go
History View file @ d153513
... ... 
@@ -2,6 +2,8 @@ package chrootarchive
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 import (
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 	"fmt"
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+	"io"
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+	"io/ioutil"
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 	"os"
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 	"github.com/docker/docker/pkg/reexec"
... ... 
@@ -16,3 +18,9 @@ func fatal(err error) {
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 	fmt.Fprint(os.Stderr, err)
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 	os.Exit(1)
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 }
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+
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+// flush consumes all the bytes from the reader discarding
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+// any errors
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+func flush(r io.Reader) {
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+	io.Copy(ioutil.Discard, r)
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+}