go-bindata: github.com/jteeuwen/go-bindata Index | Files | Directories

package bindata

import "github.com/jteeuwen/go-bindata"

bindata converts any file into managable Go source code. Useful for embedding binary data into a go program. The file data is optionally gzip compressed before being converted to a raw byte slice.

The following paragraphs cover some of the customization options which can be specified in the Config struct, which must be passed into the Translate() call.

Debug vs Release builds

When used with the `Debug` option, the generated code does not actually include the asset data. Instead, it generates function stubs which load the data from the original file on disk. The asset API remains identical between debug and release builds, so your code will not have to change.

This is useful during development when you expect the assets to change often. The host application using these assets uses the same API in both cases and will not have to care where the actual data comes from.

An example is a Go webserver with some embedded, static web content like HTML, JS and CSS files. While developing it, you do not want to rebuild the whole server and restart it every time you make a change to a bit of javascript. You just want to build and launch the server once. Then just press refresh in the browser to see those changes. Embedding the assets with the `debug` flag allows you to do just that. When you are finished developing and ready for deployment, just re-invoke `go-bindata` without the `-debug` flag. It will now embed the latest version of the assets.

Lower memory footprint

The `NoMemCopy` option will alter the way the output file is generated. It will employ a hack that allows us to read the file data directly from the compiled program's `.rodata` section. This ensures that when we call call our generated function, we omit unnecessary memcopies.

The downside of this, is that it requires dependencies on the `reflect` and `unsafe` packages. These may be restricted on platforms like AppEngine and thus prevent you from using this mode.

Another disadvantage is that the byte slice we create, is strictly read-only. For most use-cases this is not a problem, but if you ever try to alter the returned byte slice, a runtime panic is thrown. Use this mode only on target platforms where memory constraints are an issue.

The default behaviour is to use the old code generation method. This prevents the two previously mentioned issues, but will employ at least one extra memcopy and thus increase memory requirements.

For instance, consider the following two examples:

This would be the default mode, using an extra memcopy but gives a safe implementation without dependencies on `reflect` and `unsafe`:

func myfile() []byte {
	return []byte{0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a}
}

Here is the same functionality, but uses the `.rodata` hack. The byte slice returned from this example can not be written to without generating a runtime error.

var _myfile = "\x89\x50\x4e\x47\x0d\x0a\x1a"

func myfile() []byte {
	var empty [0]byte
	sx := (*reflect.StringHeader)(unsafe.Pointer(&_myfile))
	b := empty[:]
	bx := (*reflect.SliceHeader)(unsafe.Pointer(&b))
	bx.Data = sx.Data
	bx.Len = len(_myfile)
	bx.Cap = bx.Len
	return b
}

Optional compression

The NoCompress option indicates that the supplied assets are *not* GZIP compressed before being turned into Go code. The data should still be accessed through a function call, so nothing changes in the API.

This feature is useful if you do not care for compression, or the supplied resource is already compressed. Doing it again would not add any value and may even increase the size of the data.

The default behaviour of the program is to use compression.

Path prefix stripping

The keys used in the `_bindata` map are the same as the input file name passed to `go-bindata`. This includes the path. In most cases, this is not desireable, as it puts potentially sensitive information in your code base. For this purpose, the tool supplies another command line flag `-prefix`. This accepts a portion of a path name, which should be stripped off from the map keys and function names.

For example, running without the `-prefix` flag, we get:

$ go-bindata /path/to/templates/

_bindata["/path/to/templates/foo.html"] = path_to_templates_foo_html

Running with the `-prefix` flag, we get:

$ go-bindata -prefix "/path/to/" /path/to/templates/

_bindata["templates/foo.html"] = templates_foo_html

Build tags

With the optional Tags field, you can specify any go build tags that must be fulfilled for the output file to be included in a build. This is useful when including binary data in multiple formats, where the desired format is specified at build time with the appropriate tags.

The tags are appended to a `// +build` line in the beginning of the output file and must follow the build tags syntax specified by the go tool.

Index

Package Files

asset.go bytewriter.go config.go convert.go debug.go doc.go release.go restore.go stringwriter.go toc.go

func Translate Uses

func Translate(c *Config) error

Translate reads assets from an input directory, converts them to Go code and writes new files to the output specified in the given configuration.

type Asset Uses

type Asset struct {
    Path string // Full file path.
    Name string // Key used in TOC -- name by which asset is referenced.
    Func string // Function name for the procedure returning the asset contents.
}

Asset holds information about a single asset to be processed.

type ByName Uses

type ByName []os.FileInfo

Implement sort.Interface for []os.FileInfo based on Name()

func (ByName) Len Uses

func (v ByName) Len() int

func (ByName) Less Uses

func (v ByName) Less(i, j int) bool

func (ByName) Swap Uses

func (v ByName) Swap(i, j int)

type ByteWriter Uses

type ByteWriter struct {
    io.Writer
    // contains filtered or unexported fields
}

func (*ByteWriter) Write Uses

func (w *ByteWriter) Write(p []byte) (n int, err error)

type Config Uses

type Config struct {
    // Name of the package to use. Defaults to 'main'.
    Package string

    // Tags specify a set of optional build tags, which should be
    // included in the generated output. The tags are appended to a
    // `// +build` line in the beginning of the output file
    // and must follow the build tags syntax specified by the go tool.
    Tags string

    // Input defines the directory path, containing all asset files as
    // well as whether to recursively process assets in any sub directories.
    Input []InputConfig

    // Output defines the output file for the generated code.
    // If left empty, this defaults to 'bindata.go' in the current
    // working directory.
    Output string

    // Prefix defines a path prefix which should be stripped from all
    // file names when generating the keys in the table of contents.
    // For example, running without the `-prefix` flag, we get:
    //
    // 	$ go-bindata /path/to/templates
    // 	go_bindata["/path/to/templates/foo.html"] = _path_to_templates_foo_html
    //
    // Running with the `-prefix` flag, we get:
    //
    // 	$ go-bindata -prefix "/path/to/" /path/to/templates/foo.html
    // 	go_bindata["templates/foo.html"] = templates_foo_html
    Prefix string

    // NoMemCopy will alter the way the output file is generated.
    //
    // It will employ a hack that allows us to read the file data directly from
    // the compiled program's `.rodata` section. This ensures that when we call
    // call our generated function, we omit unnecessary mem copies.
    //
    // The downside of this, is that it requires dependencies on the `reflect` and
    // `unsafe` packages. These may be restricted on platforms like AppEngine and
    // thus prevent you from using this mode.
    //
    // Another disadvantage is that the byte slice we create, is strictly read-only.
    // For most use-cases this is not a problem, but if you ever try to alter the
    // returned byte slice, a runtime panic is thrown. Use this mode only on target
    // platforms where memory constraints are an issue.
    //
    // The default behaviour is to use the old code generation method. This
    // prevents the two previously mentioned issues, but will employ at least one
    // extra memcopy and thus increase memory requirements.
    //
    // For instance, consider the following two examples:
    //
    // This would be the default mode, using an extra memcopy but gives a safe
    // implementation without dependencies on `reflect` and `unsafe`:
    //
    // 	func myfile() []byte {
    // 		return []byte{0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a}
    // 	}
    //
    // Here is the same functionality, but uses the `.rodata` hack.
    // The byte slice returned from this example can not be written to without
    // generating a runtime error.
    //
    // 	var _myfile = "\x89\x50\x4e\x47\x0d\x0a\x1a"
    //
    // 	func myfile() []byte {
    // 		var empty [0]byte
    // 		sx := (*reflect.StringHeader)(unsafe.Pointer(&_myfile))
    // 		b := empty[:]
    // 		bx := (*reflect.SliceHeader)(unsafe.Pointer(&b))
    // 		bx.Data = sx.Data
    // 		bx.Len = len(_myfile)
    // 		bx.Cap = bx.Len
    // 		return b
    // 	}
    NoMemCopy bool

    // NoCompress means the assets are /not/ GZIP compressed before being turned
    // into Go code. The generated function will automatically unzip
    // the file data when called. Defaults to false.
    NoCompress bool

    // Perform a debug build. This generates an asset file, which
    // loads the asset contents directly from disk at their original
    // location, instead of embedding the contents in the code.
    //
    // This is mostly useful if you anticipate that the assets are
    // going to change during your development cycle. You will always
    // want your code to access the latest version of the asset.
    // Only in release mode, will the assets actually be embedded
    // in the code. The default behaviour is Release mode.
    Debug bool

    // Perform a dev build, which is nearly identical to the debug option. The
    // only difference is that instead of absolute file paths in generated code,
    // it expects a variable, `rootDir`, to be set in the generated code's
    // package (the author needs to do this manually), which it then prepends to
    // an asset's name to construct the file path on disk.
    //
    // This is mainly so you can push the generated code file to a shared
    // repository.
    Dev bool

    // When true, size, mode and modtime are not preserved from files
    NoMetadata bool
    // When nonzero, use this as mode for all files.
    Mode uint
    // When nonzero, use this as unix timestamp for all files.
    ModTime int64

    // Ignores any filenames matching the regex pattern specified, e.g.
    // path/to/file.ext will ignore only that file, or \\.gitignore
    // will match any .gitignore file.
    //
    // This parameter can be provided multiple times.
    Ignore []*regexp.Regexp
}

Config defines a set of options for the asset conversion.

func NewConfig Uses

func NewConfig() *Config

NewConfig returns a default configuration struct.

type InputConfig Uses

type InputConfig struct {
    // Path defines a directory containing asset files to be included
    // in the generated output.
    Path string

    // Recusive defines whether subdirectories of Path
    // should be recursively included in the conversion.
    Recursive bool
}

InputConfig defines options on a asset directory to be convert.

type StringWriter Uses

type StringWriter struct {
    io.Writer
    // contains filtered or unexported fields
}

func (*StringWriter) Write Uses

func (w *StringWriter) Write(p []byte) (n int, err error)

Directories

PathSynopsis
go-bindata

Package bindata imports 13 packages (graph) and is imported by 21 packages. Updated 2017-03-27. Refresh now. Tools for package owners.