by vapor-community

GitHub Readme.md

Heroku buildpack: swift

This is a Heroku buildpack for Swift apps that are powered by the Swift Package Manager.


Example usage:

$ ls
Procfile Package.swift Sources

$ heroku create --buildpack https://github.com/vapor-community/heroku-buildpack.git

$ git push heroku master
remote: -----> Swift app detected
remote: -----> Installing clang 5.0.0
remote: -----> Installing swiftenv
remote: -----> Installing Swift 4.1.1
remote: -----> Building package (release configuration)
remote: -----> Installing dynamic libraries
remote: -----> Installing binaries

You can also add it to upcoming builds of an existing application:

$ heroku buildpacks:set https://github.com/vapor-community/heroku-buildpack.git

The buildpack will detect your app as Swift if it has a Package.swift file in the root.


Using the Procfile, you can set the process to run for your web server. Any binaries built from your Swift source using swift package manager will be placed in your $PATH.

Example Procfile for Vapor 2 apps:

web: Run --env=production --port=$PORT

Example Procfile for Vapor 3 apps (Swift 4.1 required):

web: Run serve --env production --hostname --port $PORT

Specify a Swift version

You can also customise the version of Swift used with a .swift-version file in your repository:

$ cat .swift-version

The .swift-version file is completely compatible with swiftenv.

NOTE: Since there are frequent Swift language changes, it's advised that you pin to your Swift version.

Active build configuration

By default, the buildpack will use the release build configuration to enable compiler optimizations. If you are experiencing mysterious crashes, you can try disabling them by setting the SWIFT_BUILD_CONFIGURATION to debug, then redeploying.

$ heroku config:set SWIFT_BUILD_CONFIGURATION=debug
$ git commit -m "Change to debug configuration on Heroku" --allow-empty
$ git push heroku master
remote: -----> Building package (debug configuration)


You can place custom scripts to be ran before and after compiling your Swift source code inside the following files in your repository:

  • bin/pre_compile
  • bin/post_compile

This is useful if you would need to install any other dependencies.