Refactor utils/utils, fixes #11923

Signed-off-by: Antonio Murdaca <me@runcom.ninja>

fileutils/fileutils.go

@@ -1,6 +1,10 @@
 package fileutils
 
 import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
 	"path/filepath"
 
 	"github.com/Sirupsen/logrus"
@@ -25,3 +29,53 @@ func Matches(relFilePath string, patterns []string) (bool, error) {
 	}
 	return false, nil
 }
+
+func CopyFile(src, dst string) (int64, error) {
+	if src == dst {
+		return 0, nil
+	}
+	sf, err := os.Open(src)
+	if err != nil {
+		return 0, err
+	}
+	defer sf.Close()
+	if err := os.Remove(dst); err != nil && !os.IsNotExist(err) {
+		return 0, err
+	}
+	df, err := os.Create(dst)
+	if err != nil {
+		return 0, err
+	}
+	defer df.Close()
+	return io.Copy(df, sf)
+}
+
+func GetTotalUsedFds() int {
+	if fds, err := ioutil.ReadDir(fmt.Sprintf("/proc/%d/fd", os.Getpid())); err != nil {
+		logrus.Errorf("Error opening /proc/%d/fd: %s", os.Getpid(), err)
+	} else {
+		return len(fds)
+	}
+	return -1
+}
+
+// ReadSymlinkedDirectory returns the target directory of a symlink.
+// The target of the symbolic link may not be a file.
+func ReadSymlinkedDirectory(path string) (string, error) {
+	var realPath string
+	var err error
+	if realPath, err = filepath.Abs(path); err != nil {
+		return "", fmt.Errorf("unable to get absolute path for %s: %s", path, err)
+	}
+	if realPath, err = filepath.EvalSymlinks(realPath); err != nil {
+		return "", fmt.Errorf("failed to canonicalise path for %s: %s", path, err)
+	}
+	realPathInfo, err := os.Stat(realPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to stat target '%s' of '%s': %s", realPath, path, err)
+	}
+	if !realPathInfo.Mode().IsDir() {
+		return "", fmt.Errorf("canonical path points to a file '%s'", realPath)
+	}
+	return realPath, nil
+}

fileutils/fileutils_test.go

@@ -0,0 +1,81 @@
+package fileutils
+
+import (
+	"os"
+	"testing"
+)
+
+// Reading a symlink to a directory must return the directory
+func TestReadSymlinkedDirectoryExistingDirectory(t *testing.T) {
+	var err error
+	if err = os.Mkdir("/tmp/testReadSymlinkToExistingDirectory", 0777); err != nil {
+		t.Errorf("failed to create directory: %s", err)
+	}
+
+	if err = os.Symlink("/tmp/testReadSymlinkToExistingDirectory", "/tmp/dirLinkTest"); err != nil {
+		t.Errorf("failed to create symlink: %s", err)
+	}
+
+	var path string
+	if path, err = ReadSymlinkedDirectory("/tmp/dirLinkTest"); err != nil {
+		t.Fatalf("failed to read symlink to directory: %s", err)
+	}
+
+	if path != "/tmp/testReadSymlinkToExistingDirectory" {
+		t.Fatalf("symlink returned unexpected directory: %s", path)
+	}
+
+	if err = os.Remove("/tmp/testReadSymlinkToExistingDirectory"); err != nil {
+		t.Errorf("failed to remove temporary directory: %s", err)
+	}
+
+	if err = os.Remove("/tmp/dirLinkTest"); err != nil {
+		t.Errorf("failed to remove symlink: %s", err)
+	}
+}
+
+// Reading a non-existing symlink must fail
+func TestReadSymlinkedDirectoryNonExistingSymlink(t *testing.T) {
+	var path string
+	var err error
+	if path, err = ReadSymlinkedDirectory("/tmp/test/foo/Non/ExistingPath"); err == nil {
+		t.Fatalf("error expected for non-existing symlink")
+	}
+
+	if path != "" {
+		t.Fatalf("expected empty path, but '%s' was returned", path)
+	}
+}
+
+// Reading a symlink to a file must fail
+func TestReadSymlinkedDirectoryToFile(t *testing.T) {
+	var err error
+	var file *os.File
+
+	if file, err = os.Create("/tmp/testReadSymlinkToFile"); err != nil {
+		t.Fatalf("failed to create file: %s", err)
+	}
+
+	file.Close()
+
+	if err = os.Symlink("/tmp/testReadSymlinkToFile", "/tmp/fileLinkTest"); err != nil {
+		t.Errorf("failed to create symlink: %s", err)
+	}
+
+	var path string
+	if path, err = ReadSymlinkedDirectory("/tmp/fileLinkTest"); err == nil {
+		t.Fatalf("ReadSymlinkedDirectory on a symlink to a file should've failed")
+	}
+
+	if path != "" {
+		t.Fatalf("path should've been empty: %s", path)
+	}
+
+	if err = os.Remove("/tmp/testReadSymlinkToFile"); err != nil {
+		t.Errorf("failed to remove file: %s", err)
+	}
+
+	if err = os.Remove("/tmp/fileLinkTest"); err != nil {
+		t.Errorf("failed to remove symlink: %s", err)
+	}
+}

httputils/httputils.go

@@ -0,0 +1,26 @@
+package httputils
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/docker/docker/pkg/jsonmessage"
+)
+
+// Request a given URL and return an io.Reader
+func Download(url string) (resp *http.Response, err error) {
+	if resp, err = http.Get(url); err != nil {
+		return nil, err
+	}
+	if resp.StatusCode >= 400 {
+		return nil, fmt.Errorf("Got HTTP status code >= 400: %s", resp.Status)
+	}
+	return resp, nil
+}
+
+func NewHTTPRequestError(msg string, res *http.Response) error {
+	return &jsonmessage.JSONError{
+		Message: msg,
+		Code:    res.StatusCode,
+	}
+}

ioutils/readers.go

@@ -3,6 +3,8 @@ package ioutils
 import (
 	"bytes"
 	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
 	"io"
 	"math/big"
 	"sync"
@@ -215,3 +217,11 @@ func (r *bufReader) Close() error {
 	}
 	return closer.Close()
 }
+
+func HashData(src io.Reader) (string, error) {
+	h := sha256.New()
+	if _, err := io.Copy(h, src); err != nil {
+		return "", err
+	}
+	return "sha256:" + hex.EncodeToString(h.Sum(nil)), nil
+}

ioutils/writers.go

@@ -37,3 +37,24 @@ func NewWriteCloserWrapper(r io.Writer, closer func() error) io.WriteCloser {
 		closer: closer,
 	}
 }
+
+// Wrap a concrete io.Writer and hold a count of the number
+// of bytes written to the writer during a "session".
+// This can be convenient when write return is masked
+// (e.g., json.Encoder.Encode())
+type WriteCounter struct {
+	Count  int64
+	Writer io.Writer
+}
+
+func NewWriteCounter(w io.Writer) *WriteCounter {
+	return &WriteCounter{
+		Writer: w,
+	}
+}
+
+func (wc *WriteCounter) Write(p []byte) (count int, err error) {
+	count, err = wc.Writer.Write(p)
+	wc.Count += int64(count)
+	return
+}

ioutils/writers_test.go

@@ -0,0 +1,41 @@
+package ioutils
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestNopWriter(t *testing.T) {
+	nw := &NopWriter{}
+	l, err := nw.Write([]byte{'c'})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if l != 1 {
+		t.Fatalf("Expected 1 got %d", l)
+	}
+}
+
+func TestWriteCounter(t *testing.T) {
+	dummy1 := "This is a dummy string."
+	dummy2 := "This is another dummy string."
+	totalLength := int64(len(dummy1) + len(dummy2))
+
+	reader1 := strings.NewReader(dummy1)
+	reader2 := strings.NewReader(dummy2)
+
+	var buffer bytes.Buffer
+	wc := NewWriteCounter(&buffer)
+
+	reader1.WriteTo(wc)
+	reader2.WriteTo(wc)
+
+	if wc.Count != totalLength {
+		t.Errorf("Wrong count: %d vs. %d", wc.Count, totalLength)
+	}
+
+	if buffer.String() != dummy1+dummy2 {
+		t.Error("Wrong message written")
+	}
+}

requestdecorator/requestdecorator_test.go

@@ -180,8 +180,8 @@ func TestRequestFactory(t *testing.T) {
 
 	requestFactory := NewRequestFactory(ad, uad)
 
-	if dlen := len(requestFactory.GetDecorators()); dlen != 2 {
-		t.Fatalf("Expected to have two decorators, got %d", dlen)
+	if l := len(requestFactory.GetDecorators()); l != 2 {
+		t.Fatalf("Expected to have two decorators, got %d", l)
 	}
 
 	req, err := requestFactory.NewRequest("GET", "/test", strings.NewReader("test"))
@@ -209,8 +209,8 @@ func TestRequestFactoryNewRequestWithDecorators(t *testing.T) {
 
 	requestFactory := NewRequestFactory(ad)
 
-	if dlen := len(requestFactory.GetDecorators()); dlen != 1 {
-		t.Fatalf("Expected to have one decorators, got %d", dlen)
+	if l := len(requestFactory.GetDecorators()); l != 1 {
+		t.Fatalf("Expected to have one decorators, got %d", l)
 	}
 
 	ad2 := NewAuthDecorator("test2", "password2")
@@ -235,15 +235,15 @@ func TestRequestFactoryNewRequestWithDecorators(t *testing.T) {
 func TestRequestFactoryAddDecorator(t *testing.T) {
 	requestFactory := NewRequestFactory()
 
-	if dlen := len(requestFactory.GetDecorators()); dlen != 0 {
-		t.Fatalf("Expected to have zero decorators, got %d", dlen)
+	if l := len(requestFactory.GetDecorators()); l != 0 {
+		t.Fatalf("Expected to have zero decorators, got %d", l)
 	}
 
 	ad := NewAuthDecorator("test", "password")
 	requestFactory.AddDecorator(ad)
 
-	if dlen := len(requestFactory.GetDecorators()); dlen != 1 {
-		t.Fatalf("Expected to have one decorators, got %d", dlen)
+	if l := len(requestFactory.GetDecorators()); l != 1 {
+		t.Fatalf("Expected to have one decorators, got %d", l)
 	}
 }
 

resolvconf/resolvconf.go

@@ -9,7 +9,7 @@ import (
 	"sync"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/docker/docker/utils"
+	"github.com/docker/docker/pkg/ioutils"
 )
 
 var (
@@ -59,7 +59,7 @@ func GetIfChanged() ([]byte, string, error) {
 	if err != nil {
 		return nil, "", err
 	}
-	newHash, err := utils.HashData(bytes.NewReader(resolv))
+	newHash, err := ioutils.HashData(bytes.NewReader(resolv))
 	if err != nil {
 		return nil, "", err
 	}

stringutils/stringutils.go

@@ -1,7 +1,9 @@
 package stringutils
 
 import (
+	"bytes"
 	mathrand "math/rand"
+	"strings"
 	"time"
 )
 
@@ -28,3 +30,57 @@ func GenerateRandomAsciiString(n int) string {
 	}
 	return string(res)
 }
+
+// Truncate a string to maxlen
+func Truncate(s string, maxlen int) string {
+	if len(s) <= maxlen {
+		return s
+	}
+	return s[:maxlen]
+}
+
+// Test wheather a string is contained in a slice of strings or not.
+// Comparison is case insensitive
+func InSlice(slice []string, s string) bool {
+	for _, ss := range slice {
+		if strings.ToLower(s) == strings.ToLower(ss) {
+			return true
+		}
+	}
+	return false
+}
+
+func quote(word string, buf *bytes.Buffer) {
+	// Bail out early for "simple" strings
+	if word != "" && !strings.ContainsAny(word, "\\'\"`${[|&;<>()~*?! \t\n") {
+		buf.WriteString(word)
+		return
+	}
+
+	buf.WriteString("'")
+
+	for i := 0; i < len(word); i++ {
+		b := word[i]
+		if b == '\'' {
+			// Replace literal ' with a close ', a \', and a open '
+			buf.WriteString("'\\''")
+		} else {
+			buf.WriteByte(b)
+		}
+	}
+
+	buf.WriteString("'")
+}
+
+// Take a list of strings and escape them so they will be handled right
+// when passed as arguments to an program via a shell
+func ShellQuoteArguments(args []string) string {
+	var buf bytes.Buffer
+	for i, arg := range args {
+		if i != 0 {
+			buf.WriteByte(' ')
+		}
+		quote(arg, &buf)
+	}
+	return buf.String()
+}

stringutils/stringutils_test.go

@@ -56,3 +56,32 @@ func TestGenerateRandomAsciiStringIsAscii(t *testing.T) {
 		t.Fatalf("%s contained non-ascii characters", str)
 	}
 }
+
+func TestTruncate(t *testing.T) {
+	str := "teststring"
+	newstr := Truncate(str, 4)
+	if newstr != "test" {
+		t.Fatalf("Expected test, got %s", newstr)
+	}
+	newstr = Truncate(str, 20)
+	if newstr != "teststring" {
+		t.Fatalf("Expected teststring, got %s", newstr)
+	}
+}
+
+func TestInSlice(t *testing.T) {
+	slice := []string{"test", "in", "slice"}
+
+	test := InSlice(slice, "test")
+	if !test {
+		t.Fatalf("Expected string test to be in slice")
+	}
+	test = InSlice(slice, "SLICE")
+	if !test {
+		t.Fatalf("Expected string SLICE to be in slice")
+	}
+	test = InSlice(slice, "notinslice")
+	if test {
+		t.Fatalf("Expected string notinslice not to be in slice")
+	}
+}