Handle relative source mounts

With this change it is now possible to give a relative path to the --volume and
--mount flags.

$ docker run --mount type=bind,source=./,target=/test ...

$ docker run -v .:/test ...

Fixes #1203

Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>

cli/command/container/opts.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"path/filepath"
 	"reflect"
 	"regexp"
 	"strconv"
@@ -15,6 +16,7 @@ import (
 	"github.com/docker/cli/cli/compose/loader"
 	"github.com/docker/cli/opts"
 	"github.com/docker/docker/api/types/container"
+	mounttypes "github.com/docker/docker/api/types/mount"
 	networktypes "github.com/docker/docker/api/types/network"
 	"github.com/docker/docker/api/types/strslice"
 	"github.com/docker/docker/api/types/versions"
@@ -348,10 +350,25 @@ func parse(flags *pflag.FlagSet, copts *containerOptions, serverOS string) (*con
 	// add any bind targets to the list of container volumes
 	for bind := range copts.volumes.GetMap() {
 		parsed, _ := loader.ParseVolume(bind)
+
 		if parsed.Source != "" {
+			toBind := bind
+
+			if parsed.Type == string(mounttypes.TypeBind) {
+				if arr := strings.SplitN(bind, ":", 2); len(arr) == 2 {
+					hostPart := arr[0]
+					if strings.HasPrefix(hostPart, "."+string(filepath.Separator)) || hostPart == "." {
+						if absHostPart, err := filepath.Abs(hostPart); err == nil {
+							hostPart = absHostPart
+						}
+					}
+					toBind = hostPart + ":" + arr[1]
+				}
+			}
+
 			// after creating the bind mount we want to delete it from the copts.volumes values because
 			// we do not want bind mounts being committed to image configs
-			binds = append(binds, bind)
+			binds = append(binds, toBind)
 			// We should delete from the map (`volumes`) here, as deleting from copts.volumes will not work if
 			// there are duplicates entries.
 			delete(volumes, bind)

opts/mount.go

@@ -4,6 +4,7 @@ import (
 	"encoding/csv"
 	"fmt"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -92,6 +93,11 @@ func (m *MountOpt) Set(value string) error {
 			mount.Type = mounttypes.Type(strings.ToLower(value))
 		case "source", "src":
 			mount.Source = value
+			if strings.HasPrefix(value, "."+string(filepath.Separator)) || value == "." {
+				if abs, err := filepath.Abs(value); err == nil {
+					mount.Source = abs
+				}
+			}
 		case "target", "dst", "destination":
 			mount.Target = value
 		case "readonly", "ro":

opts/mount_test.go

@@ -2,6 +2,7 @@ package opts
 
 import (
 	"os"
+	"path/filepath"
 	"testing"
 
 	mounttypes "github.com/docker/docker/api/types/mount"
@@ -28,6 +29,40 @@ func TestMountOptString(t *testing.T) {
 	assert.Check(t, is.Equal(expected, mount.String()))
 }
 
+func TestMountRelative(t *testing.T) {
+
+	for _, testcase := range []struct {
+		name string
+		path string
+		bind string
+	}{
+		{
+			name: "Current path",
+			path: ".",
+			bind: "type=bind,source=.,target=/target",
+		}, {
+			name: "Current path with slash",
+			path: "./",
+			bind: "type=bind,source=./,target=/target",
+		},
+	} {
+		t.Run(testcase.name, func(t *testing.T) {
+			var mount MountOpt
+			assert.NilError(t, mount.Set(testcase.bind))
+
+			mounts := mount.Value()
+			assert.Assert(t, is.Len(mounts, 1))
+			abs, err := filepath.Abs(testcase.path)
+			assert.NilError(t, err)
+			assert.Check(t, is.DeepEqual(mounttypes.Mount{
+				Type:   mounttypes.TypeBind,
+				Source: abs,
+				Target: "/target",
+			}, mounts[0]))
+		})
+	}
+}
+
 func TestMountOptSetBindNoErrorBind(t *testing.T) {
 	for _, testcase := range []string{
 		// tests several aliases that should have same result.