Allow configuring app directory/path binaries are placed into

docs/configuration.md

@@ -183,6 +183,18 @@ influence the build process.
 | `KO_CONFIG_PATH` | `./.ko.yaml`                               | Path to `ko` configuration file (optional)                                                                                                                                                                                       |
 | `KOCACHE`        | (not set)                                  | This tells `ko` to store a local mapping between the `go build` inputs to the image layer that they produce, so `go build` can be skipped entirely if the layer is already present in the image registry (optional).             |
 
+## Overwriting which directory binaries are placed in
+
+By default `ko` places executable binaries of your application into `/ko-app`.
+
+As it is sometimes desirable to place an executable into a specific folder inside
+the container, or into a default executable path like `/bin` or `/usr/local/bin`,
+this directory can be overwritten.
+
+This custom path can be defined either
+- via the `--app-dir` command line flag
+- or a `defaultAppDirectory` entry in the `.ko.yaml` file.
+
 ## Naming Images
 
 `ko` provides a few different strategies for naming the image it pushes, to

docs/reference/ko_apply.md

@@ -45,6 +45,7 @@ ko apply -f FILENAME [flags]
 ### Options
 
 ```
+      --app-dir string           Directory the application binaries should be placed inside the container instead of default /ko-app.
       --bare                     Whether to just use KO_DOCKER_REPO without additional context (may not work properly with --tags).
   -B, --base-import-paths        Whether to use the base path without MD5 hash after KO_DOCKER_REPO (may not work properly with --tags).
       --debug                    Include Delve debugger into image and wrap around ko-app. This debugger will listen to port 40000.

docs/reference/ko_build.md

@@ -42,6 +42,7 @@ ko build IMPORTPATH... [flags]
 ### Options
 
 ```
+      --app-dir string           Directory the application binaries should be placed inside the container instead of default /ko-app.
       --bare                     Whether to just use KO_DOCKER_REPO without additional context (may not work properly with --tags).
   -B, --base-import-paths        Whether to use the base path without MD5 hash after KO_DOCKER_REPO (may not work properly with --tags).
       --debug                    Include Delve debugger into image and wrap around ko-app. This debugger will listen to port 40000.

docs/reference/ko_create.md

@@ -45,6 +45,7 @@ ko create -f FILENAME [flags]
 ### Options
 
 ```
+      --app-dir string           Directory the application binaries should be placed inside the container instead of default /ko-app.
       --bare                     Whether to just use KO_DOCKER_REPO without additional context (may not work properly with --tags).
   -B, --base-import-paths        Whether to use the base path without MD5 hash after KO_DOCKER_REPO (may not work properly with --tags).
       --debug                    Include Delve debugger into image and wrap around ko-app. This debugger will listen to port 40000.

docs/reference/ko_resolve.md

@@ -38,6 +38,7 @@ ko resolve -f FILENAME [flags]
 ### Options
 
 ```
+      --app-dir string           Directory the application binaries should be placed inside the container instead of default /ko-app.
       --bare                     Whether to just use KO_DOCKER_REPO without additional context (may not work properly with --tags).
   -B, --base-import-paths        Whether to use the base path without MD5 hash after KO_DOCKER_REPO (may not work properly with --tags).
       --debug                    Include Delve debugger into image and wrap around ko-app. This debugger will listen to port 40000.

docs/reference/ko_run.md

@@ -30,6 +30,7 @@ ko run IMPORTPATH [flags]
 ### Options
 
 ```
+      --app-dir string           Directory the application binaries should be placed inside the container instead of default /ko-app.
       --bare                     Whether to just use KO_DOCKER_REPO without additional context (may not work properly with --tags).
   -B, --base-import-paths        Whether to use the base path without MD5 hash after KO_DOCKER_REPO (may not work properly with --tags).
       --debug                    Include Delve debugger into image and wrap around ko-app. This debugger will listen to port 40000.

pkg/build/gobuild.go

@@ -56,6 +56,7 @@ import (
 
 const (
 	defaultAppFilename = "ko-app"
+	defaultAppDir      = "/ko-app"
 
 	defaultGoBin = "go"         // defaults to first go binary found in PATH
 	goBinPathEnv = "KO_GO_PATH" // env lookup for optional relative or full go binary path
@@ -100,6 +101,7 @@ type gobuild struct {
 	defaultLdflags       []string
 	platformMatcher      *platformMatcher
 	dir                  string
+	appDir               string
 	labels               map[string]string
 	debug                bool
 	semaphore            *semaphore.Weighted
@@ -127,6 +129,7 @@ type gobuildOpener struct {
 	platforms            []string
 	labels               map[string]string
 	dir                  string
+	appDir               string
 	jobs                 int
 	debug                bool
 }
@@ -158,6 +161,7 @@ func (gbo *gobuildOpener) Open() (Interface, error) {
 		defaultLdflags:       gbo.defaultLdflags,
 		labels:               gbo.labels,
 		dir:                  gbo.dir,
+		appDir:               gbo.appDir,
 		debug:                gbo.debug,
 		platformMatcher:      matcher,
 		cache: &layerCache{
@@ -578,7 +582,7 @@ func appFilename(importpath string) string {
 // owner: BUILTIN/Users group: BUILTIN/Users ($sddlValue="O:BUG:BU")
 const userOwnerAndGroupSID = "AQAAgBQAAAAkAAAAAAAAAAAAAAABAgAAAAAABSAAAAAhAgAAAQIAAAAAAAUgAAAAIQIAAA=="
 
-func tarBinary(name, binary string, platform *v1.Platform, opts *layerOptions) (*bytes.Buffer, error) {
+func tarBinary(name, binary, binaryDir string, platform *v1.Platform, opts *layerOptions) (*bytes.Buffer, error) {
 	buf := bytes.NewBuffer(nil)
 	tw := tar.NewWriter(buf)
 	defer tw.Close()
@@ -587,12 +591,12 @@ func tarBinary(name, binary string, platform *v1.Platform, opts *layerOptions) (
 	// For Windows, the layer must contain a Hives/ directory, and the root
 	// of the actual filesystem goes in a Files/ directory.
 	// For Linux, the binary goes into /ko-app/
-	dirs := []string{"ko-app"}
+	dirs := []string{binaryDir}
 	if platform.OS == "windows" {
 		dirs = []string{
 			"Hives",
 			"Files",
-			"Files/ko-app",
+			path.Join("Files", binaryDir),
 		}
 		name = "Files" + name
 	}
@@ -927,6 +931,13 @@ func (g gobuild) useDebugging(platform v1.Platform) bool {
 	return g.debug && doesPlatformSupportDebugging(platform)
 }
 
+func (g gobuild) getAppDir() string {
+	if g.appDir != "" {
+		return g.appDir
+	}
+	return defaultAppDir
+}
+
 func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, platform *v1.Platform) (oci.SignedImage, error) {
 	if err := g.semaphore.Acquire(ctx, 1); err != nil {
 		return nil, err
@@ -1043,7 +1054,7 @@ func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, pl
 		},
 	})
 
-	appDir := "/ko-app"
+	appDir := g.getAppDir()
 	appFileName := appFilename(ref.Path())
 	appPath := path.Join(appDir, appFileName)
 
@@ -1054,7 +1065,7 @@ func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, pl
 	}
 
 	miss := func() (v1.Layer, error) {
-		return buildLayer(appPath, file, platform, layerMediaType, &lo)
+		return buildLayer(g.getAppDir(), appPath, file, platform, layerMediaType, &lo)
 	}
 
 	var binaryLayer v1.Layer
@@ -1089,11 +1100,11 @@ func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, pl
 		}
 		defer os.RemoveAll(filepath.Dir(delveBinary))
 
-		delvePath = path.Join("/ko-app", filepath.Base(delveBinary))
+		delvePath = path.Join(g.getAppDir(), filepath.Base(delveBinary))
 
 		// add layer with delve binary
 		delveLayer, err := g.cache.get(ctx, delveBinary, func() (v1.Layer, error) {
-			return buildLayer(delvePath, delveBinary, platform, layerMediaType, &lo)
+			return buildLayer(appDir, delvePath, delveBinary, platform, layerMediaType, &lo)
 		})
 		if err != nil {
 			return nil, fmt.Errorf("cache.get(%q): %w", delveBinary, err)
@@ -1136,15 +1147,16 @@ func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, pl
 	cfg.Config.Entrypoint = []string{appPath}
 	cfg.Config.Cmd = nil
 	if platform.OS == "windows" {
-		appPath := `C:\ko-app\` + appFileName
+		appPath := strings.Replace(path.Join("C:", g.getAppDir(), appFileName), "/", `\`, -1)
 		if g.debug {
 			cfg.Config.Entrypoint = append([]string{"C:\\" + delvePath}, delveArgs...)
 			cfg.Config.Entrypoint = append(cfg.Config.Entrypoint, appPath)
 		} else {
 			cfg.Config.Entrypoint = []string{appPath}
 		}
 
-		updatePath(cfg, `C:\ko-app`)
+		addDirPath := strings.Replace(path.Join("C:", g.getAppDir()), "/", `\`, -1)
+		updatePath(cfg, addDirPath)
 		cfg.Config.Env = append(cfg.Config.Env, `KO_DATA_PATH=C:\var\run\ko`)
 	} else {
 		if g.useDebugging(*platform) {
@@ -1200,9 +1212,9 @@ type layerOptions struct {
 	linuxCapabilities *caps.FileCaps
 }
 
-func buildLayer(appPath, file string, platform *v1.Platform, layerMediaType types.MediaType, opts *layerOptions) (v1.Layer, error) {
+func buildLayer(appDir, appPath, file string, platform *v1.Platform, layerMediaType types.MediaType, opts *layerOptions) (v1.Layer, error) {
 	// Construct a tarball with the binary and produce a layer.
-	binaryLayerBuf, err := tarBinary(appPath, file, platform, opts)
+	binaryLayerBuf, err := tarBinary(appPath, file, appDir, platform, opts)
 	if err != nil {
 		return nil, fmt.Errorf("tarring binary: %w", err)
 	}