Static content embedding for Golang, ©2017 Adrian Price. Usage indicates acceptance of the license found in the LICENSE file.
Embed is a tool for embedding static content files into a Go binary, to create
a single, self-contained binary. Embed uses build constraints to offer a development
mode that loads content from disk for rapid iteration during local development;
once content is stable, you can run go generate to update the embedded content
files, and then rebuild with different tags to serve the embedded content instead
of the files on disk.
In addition to simply embedding content within your binary, embed will minify HTML, CSS, and JavaScript; gzip files for serving to clients that accept compressed content; and calculate checksums for handling Etag-based conditional requests.
Embedding tool: go get github.com/aprice/embed/cmd/embed
Usage library: go get github.com/aprice/embed/loader
Embed can easily be run with go generate.
//go:generate embed -c "embed.json"To use embed, create a config file specifying what's to be generated:
{
"RootPath": ".",
"Recurse": true,
"IncludePattern": "",
"ExcludePattern": "(^\\.|\\.go$)",
"OutputPath": "embedded.go",
"BuildConstraints": "",
"PackageName": "embedded",
"DevOutputPath": "",
"DevBuildConstraints": "",
"MinifyTypes": {
"\\.html?$": "text/html",
"\\.css$": "text/css",
"\\.js$": "application/javascript"
},
"CompressPattern": "\\.(css|js|html)$",
"NoCompressPattern": "\\.(jpe?g|png|gif|woff2?|eot|ttf|ico)$",
"OverrideModDate": false
}The values above are the defaults.
RootPath is the directory where source files to be embedded will be scanned.
If Recurse is true, subdirectories will be scanned as well. Each entry will
be compared against IncludePattern and ExcludePattern; if a file does not
match IncludePattern or does match ExcludePattern, it will not be included.
OutputPath is the path where the embedded content go file will be written. If
BuildConstraints is not empty, it will be added to the output file; for example,
"BuildConstraints": "!dev" will result in a file that will not be built by
a build command including -tags="dev". PackageName is the package name that
will be used for the output file.
DevOutputPath and DevBuildConstraints work the same as their non-Dev
counterparts, but apply to a separate "dev mode" file; if DevOutputPath is not
empty, a dev mode file will be written which reads all content from disk instead
of using embedded content. This allows for rapid iteration during local development.
The dev mode file will use PackageName for its package.
MinifyTypes is a mapping of file name regular expressions to content types that
should be minified. Minifiers are enabled for text/html, text/css,
text/javascript (or application/javascript), and image/svg+xml. Any other
content type (or an empty content type) will not be minified. The minifier used
is github.com/tdewolff/minify.
CompressPattern is a regular expression matching file names that should be
gzip compressed for clients that accept compressed data. NoCompressPattern
is for excluding files which otherwise match CompressPattern.
If OverrideModDate is true, the modification date for embedded files will be
set to the timestamp when generation is run; otherwise, it will be the modification
date of the source files.
To reference embedded content, call the GetEmbeddedContent() function in the
package where your generated file was created. This returns a Loader, which
can be used directly as an http.Handler to serve the embedded content the
same as http.FileServer(http.Dir(RootPath)). It also exposes a GetContents()
method, for loading embedded content as a byte slice for programmatic use,
such as embedding template files.