Introduce --binary flag to override path in image

The default path is /ko-app/<binaryname>, but this allows that to be
changed from the command line.

docs/reference/ko_apply.md

@@ -47,6 +47,7 @@ ko apply -f FILENAME [flags]
 ```
       --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).
+      --binary string            Set to override binary path in image.
       --disable-optimizations    Disable optimizations when building Go code. Useful when you want to interactively debug the created container.
   -f, --filename strings         Filename, directory, or URL to files to use to create the resource
   -h, --help                     help for apply

docs/reference/ko_build.md

@@ -44,6 +44,7 @@ ko build IMPORTPATH... [flags]
 ```
       --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).
+      --binary string            Set to override binary path in image.
       --disable-optimizations    Disable optimizations when building Go code. Useful when you want to interactively debug the created container.
   -h, --help                     help for build
       --image-label strings      Which labels (key=value) to add to the image.

docs/reference/ko_create.md

@@ -47,6 +47,7 @@ ko create -f FILENAME [flags]
 ```
       --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).
+      --binary string            Set to override binary path in image.
       --disable-optimizations    Disable optimizations when building Go code. Useful when you want to interactively debug the created container.
   -f, --filename strings         Filename, directory, or URL to files to use to create the resource
   -h, --help                     help for create

docs/reference/ko_resolve.md

@@ -40,6 +40,7 @@ ko resolve -f FILENAME [flags]
 ```
       --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).
+      --binary string            Set to override binary path in image.
       --disable-optimizations    Disable optimizations when building Go code. Useful when you want to interactively debug the created container.
   -f, --filename strings         Filename, directory, or URL to files to use to create the resource
   -h, --help                     help for resolve

docs/reference/ko_run.md

@@ -32,6 +32,7 @@ ko run IMPORTPATH [flags]
 ```
       --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).
+      --binary string            Set to override binary path in image.
       --disable-optimizations    Disable optimizations when building Go code. Useful when you want to interactively debug the created container.
   -h, --help                     help for run
       --image-label strings      Which labels (key=value) to add to the image.

pkg/build/gobuild.go

@@ -77,6 +77,7 @@ type gobuild struct {
 	build                builder
 	sbom                 sbomber
 	sbomDir              string
+	binaryPath           string
 	disableOptimizations bool
 	trimpath             bool
 	buildConfigs         map[string]Config
@@ -99,6 +100,7 @@ type gobuildOpener struct {
 	build                builder
 	sbom                 sbomber
 	sbomDir              string
+	binaryPath           string
 	disableOptimizations bool
 	trimpath             bool
 	buildConfigs         map[string]Config
@@ -127,6 +129,7 @@ func (gbo *gobuildOpener) Open() (Interface, error) {
 		build:                gbo.build,
 		sbom:                 gbo.sbom,
 		sbomDir:              gbo.sbomDir,
+		binaryPath:           gbo.binaryPath,
 		disableOptimizations: gbo.disableOptimizations,
 		trimpath:             gbo.trimpath,
 		buildConfigs:         gbo.buildConfigs,
@@ -795,6 +798,10 @@ func (g *gobuild) configForImportPath(ip string) Config {
 		config.Flags = append(config.Flags, "-gcflags", "all=-N -l")
 	}
 
+	if g.binaryPath != "" {
+		config.Binary = g.binaryPath
+	}
+
 	if config.ID != "" {
 		log.Printf("Using build config %s for %s", config.ID, ip)
 	}

pkg/build/gobuild_test.go

@@ -369,6 +369,16 @@ func TestBuildConfig(t *testing.T) {
 				Flags: FlagArray{"-gcflags", "all=-N -l"},
 			},
 		},
+		{
+			description: "override binary path",
+			options: []Option{
+				WithBaseImages(nilGetBase),
+				WithBinaryPath("/mydir/myprogram"),
+			},
+			expectConfig: Config{
+				Binary: "/mydir/myprogram",
+			},
+		},
 	}
 	for _, test := range tests {
 		t.Run(test.description, func(t *testing.T) {

pkg/build/options.go

@@ -177,3 +177,12 @@ func WithSBOMDir(dir string) Option {
 		return nil
 	}
 }
+
+// WithBinaryPath is a functional option for overriding the path
+// to the executable in the output image.
+func WithBinaryPath(binaryPath string) Option {
+	return func(gbo *gobuildOpener) error {
+		gbo.binaryPath = binaryPath
+		return nil
+	}
+}

pkg/commands/options/build.go

@@ -67,6 +67,9 @@ type BuildOptions struct {
 	// `AddBuildOptions()` defaults this field to `true`.
 	Trimpath bool
 
+	// BinaryPath overrides the default path for the binary in the output image.
+	BinaryPath string
+
 	// BuildConfigs stores the per-image build config from `.ko.yaml`.
 	BuildConfigs map[string]build.Config
 }
@@ -82,6 +85,8 @@ func AddBuildOptions(cmd *cobra.Command, bo *BuildOptions) {
 		"Path to file where the SBOM will be written.")
 	cmd.Flags().StringSliceVar(&bo.Platforms, "platform", []string{},
 		"Which platform to use when pulling a multi-platform base. Format: all | <os>[/<arch>[/<variant>]][,platform]*")
+	cmd.Flags().StringVar(&bo.BinaryPath, "binary", "",
+		"Set to override binary path in image.")
 	cmd.Flags().StringSliceVar(&bo.Labels, "image-label", []string{},
 		"Which labels (key=value) to add to the image.")
 	bo.Trimpath = true

pkg/commands/resolver.go

@@ -125,6 +125,10 @@ func gobuildOptions(bo *options.BuildOptions) ([]build.Option, error) {
 		opts = append(opts, build.WithSBOMDir(bo.SBOMDir))
 	}
 
+	if bo.BinaryPath != "" {
+		opts = append(opts, build.WithBinaryPath(bo.BinaryPath))
+	}
+
 	return opts, nil
 }