Heroku Buildpack: Go

This is the Heroku buildpack for Go.

Getting Started

Follow the guide at https://devcenter.heroku.com/articles/getting-started-with-go

There's also a hello world sample app at https://github.com/heroku/go-getting-started

Example

$ ls -A1
.git
Godeps
Procfile
web.go

$ heroku create
Creating polar-waters-4785...
...

$ git push heroku master
...
-----> Fetching custom git buildpack... done
-----> Go app detected
-----> Installing go1.4.1... done
-----> Running: godep go install -tags heroku ./...
-----> Discovering process types
       Procfile declares types -> web

-----> Compressing... done, 1.6MB
-----> Launching... done, v4
       https://polar-waters-4785.herokuapp.com/ deployed to Heroku

This buildpack will detect your repository as Go if it contains a .go file.

This buildpack adds a heroku build constraint, to enable heroku-specific code. See the App Engine build constraints article for more.

Hacking on this Buildpack

To change this buildpack, fork it on GitHub. Push changes to your fork, then create a test app with --buildpack YOUR_GITHUB_GIT_URL and push to it. If you already have an existing app you may use heroku config:add BUILDPACK_URL=YOUR_GITHUB_GIT_URL instead of --buildpack.

Godeps vs .godir

This buildpack supports the use of godep, which will be used to install the project and its vendored dependencies if a Godeps/Godep.json file exists. Otherwise this buildpack requires a file named .godir in the root of your project to determine the name of the project and will use the go toolchain to download dependencies.

See Go Dependencies via Godep for more.

Using with cgo

This buildpack supports building with C dependencies via cgo. You can set config vars to specify CGO flags to, e.g., specify paths for vendored dependencies. E.g., to build gopgsqldriver, add the config var CGO_CFLAGS with the value -I/app/code/vendor/include/postgresql and include the relevant Postgres header files in vendor/include/postgresql/ in your app.

Passing a symbol (and optional string) to the linker

This buildpack supports the go linker's ability (-X symbol value) to set the value of a string at link time. This can be done by setting GO_LINKER_SYMBOL and GO_LINKER_VALUE in the application's config before pushing code. If GO_LINKER_SYMBOL is set, but GO_LINKER_VALUE isn't set then GO_LINKER_VALUE defaults to $SOURCE_VERSION.

This can be used to embed the commit sha, or other build specific data directly into the compiled executable.