Add option to create parent folders when copying files or folders to Windows containers

CHANGELOG.md

@@ -1,3 +1,9 @@
+## Unreleased
+
+### IMPROVEMENTS:
+
+* Add `windows_create_parent_dirs` option to automatically create destination parent directories on uploads to Windows containers by @wbpascal in https://github.com/hashicorp/packer-plugin-docker/pull/230
+
 ## 1.1.3 (June 9, 2026)
 
 ### BUG FIXES:

builder/docker/config.go

@@ -139,6 +139,9 @@ type Config struct {
 	// running on a windows host. This is necessary for building Windows
 	// containers, because our normal docker bindings do not work for them.
 	WindowsContainer bool `mapstructure:"windows_container" required:"false"`
+	// If true, creates parent directories for file and directory uploads to
+	// Windows containers. This only applies when `windows_container` is true.
+	WindowsCreateParentDirs bool `mapstructure:"windows_create_parent_dirs" required:"false"`
 	// Set platform if server is multi-platform capable
 	Platform string `mapstructure:"platform" required:"false"`
 
@@ -205,6 +208,9 @@ func (c *Config) Prepare(raws ...interface{}) ([]string, error) {
 
 	var errs *packersdk.MultiError
 	var warnings []string
+	if c.WindowsCreateParentDirs && !c.WindowsContainer {
+		warnings = append(warnings, "`windows_create_parent_dirs` only applies when `windows_container` is true")
+	}
 
 	if !c.BuildConfig.IsDefault() {
 		_, err := c.BuildConfig.Prepare()

builder/docker/config_test.go

@@ -6,6 +6,7 @@ package docker
 import (
 	"io/ioutil"
 	"os"
+	"strings"
 	"testing"
 )
 
@@ -149,6 +150,40 @@ func TestConfigPrepare_pull(t *testing.T) {
 	}
 }
 
+func TestConfigPrepare_windowsCreateParentDirs(t *testing.T) {
+	raw := testConfig()
+	var c Config
+	warns, errs := c.Prepare(raw)
+	testConfigOk(t, warns, errs)
+	if c.WindowsCreateParentDirs {
+		t.Fatal("windows_create_parent_dirs should default to false")
+	}
+
+	raw = testConfig()
+	raw["windows_container"] = true
+	raw["windows_create_parent_dirs"] = true
+	c = Config{}
+	warns, errs = c.Prepare(raw)
+	testConfigOk(t, warns, errs)
+	if !c.WindowsCreateParentDirs {
+		t.Fatal("windows_create_parent_dirs should be true")
+	}
+
+	raw = testConfig()
+	raw["windows_create_parent_dirs"] = true
+	c = Config{}
+	warns, errs = c.Prepare(raw)
+	if errs != nil {
+		t.Fatalf("bad: %s", errs)
+	}
+	if len(warns) != 1 {
+		t.Fatalf("expected one warning, got %#v", warns)
+	}
+	if !strings.Contains(warns[0], "windows_create_parent_dirs") {
+		t.Fatalf("expected windows_create_parent_dirs warning, got %#v", warns)
+	}
+}
+
 // Test variations of a build bootstrap config; including unset
 func TestConfigBuildBootstrapConfig(t *testing.T) {
 	tests := []struct {

builder/docker/windows_container_communicator.go

@@ -12,6 +12,7 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"strings"
 
 	packersdk "github.com/hashicorp/packer-plugin-sdk/packer"
 )
@@ -28,6 +29,28 @@ type WindowsContainerCommunicator struct {
 	Communicator
 }
 
+func powerShellSingleQuote(s string) string {
+	return "'" + strings.ReplaceAll(s, "'", "''") + "'"
+}
+
+// Creates the parent and all other preceding directories in the container for the given destination.
+// Does not recreate paths that already exist.
+func (c *WindowsContainerCommunicator) ensureContainerParentDir(ctx context.Context, destination string) error {
+	cmd := &packersdk.RemoteCmd{
+		Command: fmt.Sprintf("$parent = Split-Path -Parent %s; if ($parent -and -not (Test-Path -LiteralPath $parent)) { New-Item -ItemType Directory -Force -LiteralPath $parent -ErrorAction Stop | Out-Null }", powerShellSingleQuote(destination)),
+	}
+	if err := c.Start(ctx, cmd); err != nil {
+		return err
+	}
+
+	cmd.Wait()
+	if cmd.ExitStatus() != 0 {
+		return fmt.Errorf("Upload failed to create parent directory for %s: %d", destination, cmd.ExitStatus())
+	}
+
+	return nil
+}
+
 // Upload uses docker exec to copy the file from the host to the container
 func (c *WindowsContainerCommunicator) Upload(dst string, src io.Reader, fi *os.FileInfo) error {
 	// Create a temporary file to store the upload
@@ -48,13 +71,21 @@ func (c *WindowsContainerCommunicator) Upload(dst string, src io.Reader, fi *os.
 	}
 	tempfile.Close()
 
+	// Before copying the file into place, we need to make sure that the parent folders
+	// exists if windows_create_parent_dirs was specified in the plugin config.
+	// See also https://github.com/hashicorp/packer-plugin-docker/issues/208
+	ctx := context.TODO()
+	if c.Config.WindowsCreateParentDirs {
+		if err := c.ensureContainerParentDir(ctx, dst); err != nil {
+			return err
+		}
+	}
+
 	// Copy the file into place by copying the temporary file we put
 	// into the shared folder into the proper location in the container
 	cmd := &packersdk.RemoteCmd{
-		Command: fmt.Sprintf("Copy-Item -Path %s/%s -Destination %s", c.ContainerDir,
-			filepath.Base(tempfile.Name()), dst),
+		Command: fmt.Sprintf("Copy-Item -LiteralPath %s -Destination %s -Force", powerShellSingleQuote(filepath.Join(c.ContainerDir, filepath.Base(tempfile.Name()))), powerShellSingleQuote(dst)),
 	}
-	ctx := context.TODO()
 	if err := c.Start(ctx, cmd); err != nil {
 		return err
 	}
@@ -135,12 +166,20 @@ func (c *WindowsContainerCommunicator) UploadDir(dst string, src string, exclude
 		containerDst = filepath.Join(dst, filepath.Base(src))
 	}
 
+	// Before copying the files into place, we need to make sure that the parent folders
+	// exists if windows_create_parent_dirs was specified in the plugin config.
+	// See also https://github.com/hashicorp/packer-plugin-docker/issues/208
+	ctx := context.TODO()
+	if c.Config.WindowsCreateParentDirs {
+		if err := c.ensureContainerParentDir(ctx, containerDst); err != nil {
+			return err
+		}
+	}
+
 	// Make the directory, then copy into it
 	cmd := &packersdk.RemoteCmd{
-		Command: fmt.Sprintf("Copy-Item %s -Destination %s -Recurse",
-			containerSrc, containerDst),
+		Command: fmt.Sprintf("Copy-Item -LiteralPath %s -Destination %s -Recurse", powerShellSingleQuote(containerSrc), powerShellSingleQuote(containerDst)),
 	}
-	ctx := context.TODO()
 	if err := c.Start(ctx, cmd); err != nil {
 		return err
 	}

docs-partials/builder/docker/Config-not-required.mdx

@@ -98,6 +98,9 @@
   running on a windows host. This is necessary for building Windows
   containers, because our normal docker bindings do not work for them.
 
+- `windows_create_parent_dirs` (bool) - If true, creates parent directories for file and directory uploads to
+  Windows containers. This only applies when `windows_container` is true.
+
 - `platform` (string) - Set platform if server is multi-platform capable
 
 - `login` (bool) - This is used to login to a private docker repository (e.g., dockerhub)

docs/builders/docker.mdx

@@ -418,6 +418,11 @@ If you are building a Windows container, you must set the template option
 `"windows_container": true`. Please note that docker cannot export Windows
 containers, so you must either commit or discard them.
 
+Set `"windows_create_parent_dirs": true` to have Packer create missing parent
+directories before uploading files or directories to Windows containers. This
+helps Windows container uploads behave more like Linux container uploads that
+use `docker cp`.
+
 The following is a fully functional template for building a Windows
 container.
 
@@ -428,6 +433,7 @@ source "docker" "windows" {
     image = "microsoft/windowsservercore:1709"
     container_dir = "c:/app"
     windows_container = true
+    windows_create_parent_dirs = true
     commit = true
 }
 
@@ -446,6 +452,7 @@ build {
       "image": "microsoft/windowsservercore:1709",
       "container_dir": "c:/app",
       "windows_container": true,
+      "windows_create_parent_dirs": true,
       "commit": true
     }
   ]