refactor: move common io-related functions into new file

plugins/common/common.go

@@ -1,14 +1,12 @@
 package common
 
 import (
-	"bufio"
 	"bytes"
 	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"os/exec"
-	"os/user"
 	"path/filepath"
 	"reflect"
 	"regexp"
@@ -439,16 +437,6 @@ func ContainerIsRunning(containerID string) bool {
 	return strings.TrimSpace(string(b[:])) == "true"
 }
 
-// DirectoryExists returns if a path exists and is a directory
-func DirectoryExists(filePath string) bool {
-	fi, err := os.Stat(filePath)
-	if err != nil {
-		return false
-	}
-
-	return fi.IsDir()
-}
-
 // DockerContainerCreate creates a new container and returns the container ID
 func DockerContainerCreate(image string, containerCreateArgs []string) (string, error) {
 	cmd := []string{
@@ -513,36 +501,6 @@ func DokkuApps() (apps []string, err error) {
 	return
 }
 
-// FileToSlice reads in all the lines from a file into a string slice
-func FileToSlice(filePath string) (lines []string, err error) {
-	f, err := os.Open(filePath)
-	if err != nil {
-		return
-	}
-	defer f.Close()
-
-	scanner := bufio.NewScanner(f)
-	for scanner.Scan() {
-		text := strings.TrimSpace(scanner.Text())
-		if text == "" {
-			continue
-		}
-		lines = append(lines, text)
-	}
-	err = scanner.Err()
-	return
-}
-
-// FileExists returns if a path exists and is a file
-func FileExists(filePath string) bool {
-	fi, err := os.Stat(filePath)
-	if err != nil {
-		return false
-	}
-
-	return fi.Mode().IsRegular()
-}
-
 // GetAppImageName returns image identifier for a given app, tag tuple. validate if tag is presented
 func GetAppImageName(appName, imageTag, imageRepo string) (imageName string) {
 	err := VerifyAppName(appName)
@@ -565,11 +523,6 @@ func GetAppImageName(appName, imageTag, imageRepo string) (imageName string) {
 	return
 }
 
-// IsAbsPath returns 0 if input path is absolute
-func IsAbsPath(path string) bool {
-	return strings.HasPrefix(path, "/")
-}
-
 // IsDeployed returns true if given app has a running container
 func IsDeployed(appName string) bool {
 	files, err := ioutil.ReadDir(AppRoot(appName))
@@ -612,29 +565,6 @@ func GetenvWithDefault(key string, defaultValue string) (val string) {
 	return
 }
 
-// ReadFirstLine gets the first line of a file that has contents and returns it
-// if there are no contents, an empty string is returned
-// will also return an empty string if the file does not exist
-func ReadFirstLine(filename string) (text string) {
-	if !FileExists(filename) {
-		return
-	}
-	f, err := os.Open(filename)
-	if err != nil {
-		return
-	}
-	defer f.Close()
-
-	scanner := bufio.NewScanner(f)
-	for scanner.Scan() {
-		if text = strings.TrimSpace(scanner.Text()); text == "" {
-			continue
-		}
-		return
-	}
-	return
-}
-
 // ReportSingleApp is an internal function that displays a report for an app
 func ReportSingleApp(reportType string, appName string, infoFlag string, infoFlags map[string]string, trimPrefix bool, uppercaseFirstCharacter bool) error {
 	flags := []string{}
@@ -805,36 +735,6 @@ func PlugnTriggerSetup(triggerName string, args ...string) *sh.Session {
 	return sh.Command("plugn", shellArgs...)
 }
 
-// SetPermissions sets the proper owner and filemode for a given file
-func SetPermissions(path string, fileMode os.FileMode) error {
-	if err := os.Chmod(path, fileMode); err != nil {
-		return err
-	}
-
-	systemGroup := GetenvWithDefault("DOKKU_SYSTEM_GROUP", "dokku")
-	systemUser := GetenvWithDefault("DOKKU_SYSTEM_USER", "dokku")
-
-	group, err := user.LookupGroup(systemGroup)
-	if err != nil {
-		return err
-	}
-	user, err := user.Lookup(systemUser)
-	if err != nil {
-		return err
-	}
-
-	uid, err := strconv.Atoi(user.Uid)
-	if err != nil {
-		return err
-	}
-
-	gid, err := strconv.Atoi(group.Gid)
-	if err != nil {
-		return err
-	}
-	return os.Chown(path, uid, gid)
-}
-
 func times(str string, n int) (out string) {
 	for i := 0; i < n; i++ {
 		out += str

plugins/common/common_test.go

@@ -10,10 +10,10 @@ import (
 )
 
 var (
-	testAppName = "test-app-1"
-	testAppDir  = strings.Join([]string{"/home/dokku/", testAppName}, "")
-	testEnvFile = strings.Join([]string{testAppDir, "/ENV"}, "")
-	testEnvLine = "export testKey=TESTING"
+	testAppName  = "test-app-1"
+	testAppDir   = strings.Join([]string{"/home/dokku/", testAppName}, "")
+	testEnvFile  = strings.Join([]string{testAppDir, "/ENV"}, "")
+	testEnvLine  = "export testKey=TESTING"
 	testAppName2 = "01-test-app-1"
 	testAppDir2  = strings.Join([]string{"/home/dokku/", testAppName2}, "")
 	testEnvFile2 = strings.Join([]string{testAppDir2, "/ENV"}, "")
@@ -95,32 +95,6 @@ func TestCommonDokkuApps(t *testing.T) {
 	teardownTestApp()
 }
 
-func TestCommonFileToSlice(t *testing.T) {
-	RegisterTestingT(t)
-	Expect(setupTestApp()).To(Succeed())
-	lines, err := FileToSlice(testEnvFile)
-	Expect(err).NotTo(HaveOccurred())
-	Expect(lines).To(Equal([]string{testEnvLine}))
-	teardownTestApp()
-}
-
-func TestCommonFileExists(t *testing.T) {
-	RegisterTestingT(t)
-	Expect(setupTestApp()).To(Succeed())
-	Expect(FileExists(testEnvFile)).To(BeTrue())
-	teardownTestApp()
-}
-
-func TestCommonReadFirstLine(t *testing.T) {
-	RegisterTestingT(t)
-	line := ReadFirstLine(testEnvFile)
-	Expect(line).To(Equal(""))
-	Expect(setupTestApp()).To(Succeed())
-	line = ReadFirstLine(testEnvFile)
-	Expect(line).To(Equal(testEnvLine))
-	teardownTestApp()
-}
-
 func TestCommonStripInlineComments(t *testing.T) {
 	RegisterTestingT(t)
 	text := StripInlineComments(strings.Join([]string{testEnvLine, "# testing comment"}, " "))

plugins/common/io.go

@@ -0,0 +1,191 @@
+package common
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"os/user"
+	"strconv"
+	"strings"
+)
+
+// CopyFile copies a file from src to dst. If src and dst files exist, and are
+// the same, then return success. Otherise, attempt to create a hard link
+// between the two files. If that fail, copy the file contents from src to dst.
+// FROM: https://stackoverflow.com/a/21067803/1515875
+func CopyFile(src, dst string) (err error) {
+	sfi, err := os.Stat(src)
+	if err != nil {
+		return
+	}
+	if !sfi.Mode().IsRegular() {
+		// cannot copy non-regular files (e.g., directories,
+		// symlinks, devices, etc.)
+		return fmt.Errorf("CopyFile: non-regular source file %s (%q)", sfi.Name(), sfi.Mode().String())
+	}
+	dfi, err := os.Stat(dst)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return
+		}
+	} else {
+		if !(dfi.Mode().IsRegular()) {
+			return fmt.Errorf("CopyFile: non-regular destination file %s (%q)", dfi.Name(), dfi.Mode().String())
+		}
+		if os.SameFile(sfi, dfi) {
+			return
+		}
+	}
+	if err = os.Link(src, dst); err == nil {
+		return
+	}
+	err = copyFileContents(src, dst)
+	return
+}
+
+// copyFileContents copies the contents of the file named src to the file named
+// by dst. The file will be created if it does not already exist. If the
+// destination file exists, all it's contents will be replaced by the contents
+// of the source file.
+// FROM: https://stackoverflow.com/a/21067803/1515875
+func copyFileContents(src, dst string) (err error) {
+	in, err := os.Open(src)
+	if err != nil {
+		return
+	}
+	defer in.Close()
+	out, err := os.Create(dst)
+	if err != nil {
+		return
+	}
+	defer func() {
+		cerr := out.Close()
+		if err == nil {
+			err = cerr
+		}
+	}()
+	if _, err = io.Copy(out, in); err != nil {
+		return
+	}
+	err = out.Sync()
+	return
+}
+
+// DirectoryExists returns if a path exists and is a directory
+func DirectoryExists(filename string) bool {
+	fi, err := os.Stat(filename)
+	if err != nil {
+		return false
+	}
+
+	return fi.IsDir()
+}
+
+// FileToSlice reads in all the lines from a file into a string slice
+func FileToSlice(filename string) (lines []string, err error) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		text := strings.TrimSpace(scanner.Text())
+		if text == "" {
+			continue
+		}
+		lines = append(lines, text)
+	}
+	err = scanner.Err()
+	return
+}
+
+// FileExists returns if a path exists and is a file
+func FileExists(filename string) bool {
+	fi, err := os.Stat(filename)
+	if err != nil {
+		return false
+	}
+
+	return fi.Mode().IsRegular()
+}
+
+// IsAbsPath returns 0 if input path is absolute
+func IsAbsPath(path string) bool {
+	return strings.HasPrefix(path, "/")
+}
+
+// ReadFirstLine gets the first line of a file that has contents and returns it
+// if there are no contents, an empty string is returned
+// will also return an empty string if the file does not exist
+func ReadFirstLine(filename string) (text string) {
+	if !FileExists(filename) {
+		return
+	}
+	f, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		if text = strings.TrimSpace(scanner.Text()); text == "" {
+			continue
+		}
+		return
+	}
+	return
+}
+
+// SetPermissions sets the proper owner and filemode for a given file
+func SetPermissions(path string, fileMode os.FileMode) error {
+	if err := os.Chmod(path, fileMode); err != nil {
+		return err
+	}
+
+	systemGroup := GetenvWithDefault("DOKKU_SYSTEM_GROUP", "dokku")
+	systemUser := GetenvWithDefault("DOKKU_SYSTEM_USER", "dokku")
+
+	group, err := user.LookupGroup(systemGroup)
+	if err != nil {
+		return err
+	}
+	user, err := user.Lookup(systemUser)
+	if err != nil {
+		return err
+	}
+
+	uid, err := strconv.Atoi(user.Uid)
+	if err != nil {
+		return err
+	}
+
+	gid, err := strconv.Atoi(group.Gid)
+	if err != nil {
+		return err
+	}
+	return os.Chown(path, uid, gid)
+}
+
+func WriteSliceToFile(filename string, lines []string) error {
+	file, err := os.OpenFile(filename, os.O_RDWR|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+
+	w := bufio.NewWriter(file)
+	for _, line := range lines {
+		fmt.Fprintln(w, line)
+	}
+	if err = w.Flush(); err != nil {
+		return err
+	}
+
+	file.Chmod(0600)
+	SetPermissions(filename, 0600)
+
+	return nil
+}

plugins/common/io_test.go

@@ -0,0 +1,28 @@
+
+import "testing"
+
+func TestCommonFileToSlice(t *testing.T) {
+	RegisterTestingT(t)
+	Expect(setupTestApp()).To(Succeed())
+	lines, err := FileToSlice(testEnvFile)
+	Expect(err).NotTo(HaveOccurred())
+	Expect(lines).To(Equal([]string{testEnvLine}))
+	teardownTestApp()
+}
+
+func TestCommonFileExists(t *testing.T) {
+	RegisterTestingT(t)
+	Expect(setupTestApp()).To(Succeed())
+	Expect(FileExists(testEnvFile)).To(BeTrue())
+	teardownTestApp()
+}
+
+func TestCommonReadFirstLine(t *testing.T) {
+	RegisterTestingT(t)
+	line := ReadFirstLine(testEnvFile)
+	Expect(line).To(Equal(""))
+	Expect(setupTestApp()).To(Succeed())
+	line = ReadFirstLine(testEnvFile)
+	Expect(line).To(Equal(testEnvLine))
+	teardownTestApp()
+}

plugins/docker-options/dockeroptions.go

@@ -82,21 +82,5 @@ func touchPhaseFile(appName string, phase string) error {
 
 func writeDockerOptionsForPhase(appName string, phase string, options []string) error {
 	phaseFilePath := getPhaseFilePath(appName, phase)
-	file, err := os.OpenFile(phaseFilePath, os.O_RDWR|os.O_TRUNC, 0600)
-	if err != nil {
-		return err
-	}
-
-	w := bufio.NewWriter(file)
-	for _, option := range options {
-		fmt.Fprintln(w, option)
-	}
-	if err = w.Flush(); err != nil {
-		return fmt.Errorf("Unable to update docker options phase file %s.%s: %s", appName, phase, err.Error())
-	}
-
-	file.Chmod(0600)
-	common.SetPermissions(phaseFilePath, 0600)
-
-	return nil
+	return common.WriteSliceToFile(phaseFilePath, options)
 }