Look for docker cli next to the current executable

Signed-off-by: Mathieu Champlon <mathieu.champlon@docker.com>

cli/mobycli/exec.go

@@ -22,6 +22,7 @@ import (
 	"os"
 	"os/exec"
 	"os/signal"
+	"path/filepath"
 	"regexp"
 
 	apicontext "github.com/docker/compose-cli/api/context"
@@ -89,10 +90,13 @@ func Exec(root *cobra.Command) {
 func RunDocker(childExit chan bool, args ...string) error {
 	execBinary, err := resolvepath.LookPath(ComDockerCli)
 	if err != nil {
+		execBinary = findBinary(ComDockerCli)
+		if execBinary == "" {
 			fmt.Fprintln(os.Stderr, err)
 			fmt.Fprintln(os.Stderr, "Current PATH : "+os.Getenv("PATH"))
 			os.Exit(1)
 		}
+	}
 	cmd := exec.Command(execBinary, args...)
 	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
@@ -123,6 +127,22 @@ func RunDocker(childExit chan bool, args ...string) error {
 	return cmd.Run()
 }
 
+func findBinary(filename string) string {
+	currentBinaryPath, err := os.Executable()
+	if err != nil {
+		return ""
+	}
+	currentBinaryPath, err = filepath.EvalSymlinks(currentBinaryPath)
+	if err != nil {
+		return ""
+	}
+	binaryPath := filepath.Join(filepath.Dir(currentBinaryPath), filename)
+	if _, err := os.Stat(binaryPath); err != nil {
+		return ""
+	}
+	return binaryPath
+}
+
 // IsDefaultContextCommand checks if the command exists in the classic cli (issues a shellout --help)
 func IsDefaultContextCommand(dockerCommand string) bool {
 	cmd := exec.Command(ComDockerCli, dockerCommand, "--help")