by IBM-Swift

GitHub Readme.md

Build Status - Master

IBM Cloud buildpack for Swift

This is the IBM Cloud buildpack for Swift applications, powered by the Swift Package Manager (SPM). Though this buildpack was developed mainly for IBM Cloud and the sample commands use the IBM Cloud command line, it can be used on any Cloud Foundry environment. This buildpack requires access to the Internet for downloading and installing several system level dependencies.

Check out the Kitura-Starter for a fully working example of a Kitura-based server application that can be deployed to the IBM Cloud (or any Cloud Foundry environment).


Example usage (see the Specify a Swift version section):

$ ibmcloud app push
Invoking 'ibmcloud app push'...

Using manifest file /Users/olivieri/git/Kitura-Starter/manifest.yml

Creating app Kitura-Starter in org roliv@us.ibm.com / space dev as roliv@us.ibm.com...

Creating route kitura-starter-nonclamorous-pekin.mybluemix.net...

Binding kitura-starter-nonclamorous-pekin.mybluemix.net to Kitura-Starter...

Uploading Kitura-Starter...
Uploading app files from: /Users/olivieri/git/Kitura-Starter
Uploading 56.3K, 16 files
Done uploading               

Starting app Kitura-Starter in org roliv@us.ibm.com / space dev as roliv@us.ibm.com...
-----> Downloaded app package (28K)
Cloning into '/tmp/buildpacks/swift-buildpack'...
-----> Buildpack version 2.0.20
-----> Default supported Swift version is 5.0
-----> Configure for apt-get installs...
-----> Downloading system level dependencies...
-----> Fetching .debs for: libicu-dev libcurl4-openssl-dev
Ign http://archive.ubuntu.com trusty InRelease
Get:1 http://archive.ubuntu.com trusty-updates InRelease [65.9 kB]
Get:2 http://archive.ubuntu.com trusty-security InRelease [65.9 kB]
Get:3 http://archive.ubuntu.com trusty Release.gpg [933 B]
Get:4 http://archive.ubuntu.com trusty-updates/main amd64 Packages [1,139 kB]
Get:5 http://archive.ubuntu.com trusty-updates/universe amd64 Packages [501 kB]
Get:6 http://archive.ubuntu.com trusty-updates/multiverse amd64 Packages [16.4 kB]
Get:7 http://archive.ubuntu.com trusty Release [58.5 kB]
Get:8 http://archive.ubuntu.com trusty-security/main amd64 Packages [675 kB]
Get:9 http://archive.ubuntu.com trusty-security/universe amd64 Packages [185 kB]
Get:10 http://archive.ubuntu.com trusty-security/multiverse amd64 Packages [5,083 B]
Get:11 http://archive.ubuntu.com trusty/main amd64 Packages [1,743 kB]
Get:12 http://archive.ubuntu.com trusty/universe amd64 Packages [7,589 kB]
Get:13 http://archive.ubuntu.com trusty/multiverse amd64 Packages [169 kB]
Fetched 12.2 MB in 23s (523 kB/s)
Reading package lists...
       Reading package lists...
       Building dependency tree...
       The following extra packages will be installed:
         curl libcurl3
       Suggested packages:
         libcurl4-doc libcurl3-dbg
       The following packages will be upgraded:
         curl libcurl3 libcurl4-openssl-dev
       3 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 77 not upgraded.
       Need to get 8,129 kB of archives.
       After this operation, 1,024 B of additional disk space will be used.
       Get:1 http://archive.ubuntu.com/ubuntu/ trusty-updates/main curl amd64 7.35.0-1ubuntu2.9 [123 kB]
       Get:2 http://archive.ubuntu.com/ubuntu/ trusty-updates/main libcurl4-openssl-dev amd64 7.35.0-1ubuntu2.9 [245 kB]
       Get:4 http://archive.ubuntu.com/ubuntu/ trusty-updates/main libicu-dev amd64 52.1-3ubuntu0.4 [7,588 kB]
       Fetched 8,129 kB in 14s (551 kB/s)
       Download complete and in download only mode
-----> Downloaded DEB files...
-----> No Aptfile found.
-----> Installing system level dependencies...
-----> Installing curl_7.35.0-1ubuntu2.9_amd64.deb
-----> Installing libcurl3_7.35.0-1ubuntu2.9_amd64.deb
-----> Installing libcurl4-openssl-dev_7.35.0-1ubuntu2.9_amd64.deb
-----> Installing libicu-dev_52.1-3ubuntu0.4_amd64.deb
-----> Writing profile script...
-----> Getting swift-3.0
WARNING: Default supported Swift version: swift-3.0.1
WARNING: Requested Swift version for your app: swift-3.0
       Downloaded swift-3.0
-----> Unpacking swift-3.0.tar.gz
-----> Getting clang-3.8.0
       Downloaded clang-3.8.0
-----> Skipping cache restore (new swift signature)
-----> Building Package...
       Cloning https://github.com/IBM-Swift/Kitura.git
       HEAD is now at 43d9c17 IBM-Swift/Kitura#788 Avoid converting JSON serialized Data to String and back to Data again. (#807)
       Resolved version: 1.0.1
       Cloning https://github.com/IBM-Swift/Kitura-net.git
       HEAD is now at b61145f Merge pull request #126 from IBM-Swift/issue_784
       Resolved version: 1.0.2
       Cloning https://github.com/IBM-Swift/LoggerAPI.git
       HEAD is now at d4c1682 Regenerated API Documentation (#15)
       Resolved version: 1.0.0
       Cloning https://github.com/IBM-Swift/BlueSocket.git
       HEAD is now at 61d47f7 Update to latest (11/1) toolchain.
       Resolved version: 0.11.39
       Cloning https://github.com/IBM-Swift/CCurl.git
       HEAD is now at 3cfb752 Add header callback helper function (#9)
       Resolved version: 0.2.3
       Cloning https://github.com/IBM-Swift/CHTTPParser.git
       HEAD is now at 429eff6 Merge pull request #7 from ianpartridge/master
       Resolved version: 0.3.0
       Cloning https://github.com/IBM-Swift/BlueSSLService.git
       HEAD is now at 6659ac8 Update to latest (11/1) toolchain.
       Resolved version: 0.11.53
       Resolved version: 0.2.2
       Cloning https://github.com/IBM-Swift/CEpoll.git
       HEAD is now at 111cbcb IBM-Swift/Kitura#435 Added a README.md file
       Resolved version: 0.1.0
       Cloning https://github.com/IBM-Swift/SwiftyJSON.git
       HEAD is now at d8de7c8 Merge pull request #23 from IBM-Swift/issue_788
       Resolved version: 14.2.1
       Cloning https://github.com/IBM-Swift/Kitura-TemplateEngine.git
       HEAD is now at f013da3 Regenerated API Documentation (#8)
       Resolved version: 1.0.0
       Cloning https://github.com/IBM-Swift/HeliumLogger.git
warning: unable to rmdir Package-Builder: Directory not empty
       HEAD is now at 4a52f0b updated dependency versions in Package.swift
       Resolved version: 1.0.0
       Cloning https://github.com/IBM-Swift/Swift-cfenv.git
       HEAD is now at 3486dcb Modified parseEnvVariable() method - using now environment variables if present regardless of isLocal boolean.
       Resolved version: 1.7.1
       Compile CHTTPParser utils.c
       Compile CHTTPParser http_parser.c
       Compile Swift Module 'Socket' (3 sources)
       Compile Swift Module 'LoggerAPI' (1 sources)
       Compile Swift Module 'SwiftyJSON' (2 sources)
       Compile Swift Module 'KituraTemplateEngine' (1 sources)
       Linking CHTTPParser
       Compile Swift Module 'SSLService' (1 sources)
       Compile Swift Module 'CloudFoundryEnv' (7 sources)
       Compile Swift Module 'KituraNet' (28 sources)
       Compile Swift Module 'Kitura' (40 sources)
       Compile Swift Module 'Kitura_Starter' (2 sources)
       Linking ./.build/release/Kitura-Starter
-----> Copying dynamic libraries
-----> Copying binaries to 'bin'
-----> Cleaning up build files
-----> Clearing previous swift cache
-----> Saving cache (default):
-----> Optimizing contents of cache folder
-----> Uploading droplet (29M)

0 of 1 instances running, 1 starting
1 of 1 instances running

App started


App Kitura-Starter was started using this command `Kitura-Starter`

Showing health and status for app Kitura-Starter in org roliv@us.ibm.com / space dev as roliv@us.ibm.com...

requested state: started
instances: 1/1
usage: 256M x 1 instances
urls: kitura-starter-nonclamorous-pekin.mybluemix.net
last uploaded: Wed Nov 2 20:58:21 UTC 2016
stack: cflinuxfs2
buildpack: swift_buildpack

     state     since                    cpu    memory          disk          details
#0   running   2016-11-02 04:03:02 PM   0.0%   29.3M of 256M   89.5M of 1G

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

Version installed on the IBM Cloud

The latest version of the IBM Cloud buildpack for Swift on the IBM Cloud is v2.0.20.

Please note that it is possible that the latest buildpack code contained in this repo hasn't yet been installed on the IBM Cloud. If that happens to be the case and you'd like to leverage the latest buildpack code, you can do so by adding the -b https://github.com/IBM-Swift/swift-buildpack parameter to the ibmcloud app push command, as shown below:

ibmcloud app push -b https://github.com/IBM-Swift/swift-buildpack


Using the Procfile, you specify the name of the executable process (e.g. Server) to run for your web server. Any binaries built from your Swift source using SPM will be placed in your $PATH. You can also specify any runtime parameters for your process in the Procfile.

web: Server --bind$PORT

Alternative to Procfile

Instead of using the Procfile, you can use the command attribute in the manifest.yml of your application to specify the name of your executable. The snippet of code below shows how to use the command attribute to specify the same executable and parameter values used in the above Procfile example:

command: Server -bind$PORT

For further details on the command attribute, see the command attribute section on the Cloud Foundry documentation.


Instead of specifying IP address and port values in the Procfile (or in the command attribute) as runtime parameters to your web server process, you can instead use the Swift-cfenv package to obtain such values at runtime. The Swift-cfenv package provides structures and methods to parse Cloud Foundry-provided environment variables, such as the port number, IP address, and URL of the application. It also provides default values when running the application locally. For details on how to leverage this library in your Swift application, see the README file. When using Swift-cfenv in your app, your Procfile will be very simple; it will more than likely look like this:

web: <executable_name>

If instead of the Procfile, you are using the command attribute in your application's manifest.yml file, then the entry for the command attribute is simplified to:

command: <executable_name>

What is the latest version of Swift supported?

The latest version of Swift supported by this buildpack is 5.0.

Specify a Swift version

You specify the version of Swift for your application using a .swift-version file in the root of your repository:

$ cat .swift-version

Please note that the swift_buildpack installed on the IBM Cloud caches the following versions of the Swift binaries:

  • 5.0
  • 4.2.4

If you'd like to use a different version of Swift [that is not cached] on the IBM Cloud, you can specify it in the .swift-version file. Please be aware that using a Swift version that is not cached increases the provisioning time of your app on the IBM Cloud.

The manifest.yml file contains the complete list of the Swift versions that are cached on the IBM Cloud.

Since there are frequent Swift language changes, it's advised that you pin your application to a specific Swift version. Once you have tested and migrated your code to a newer version of Swift, you can then update the .swift-version file with the appropriate Swift version.

Installing additional system level dependencies

Many Swift applications will not require the installation of any additional libraries. It's very common for today’s applications to have dependencies only on services that provide REST interfaces to interact with them (e.g., Cloudant, AlchemyAPI, Personality Insights, etc.).

However, since dependencies vary from application to application, there could be cases when additional system packages may be required to compile and/or execute a Swift application. To address this need, the IBM Cloud buildpack for Swift supports the installation of Ubuntu trusty packages using the apt-get utility. You can specify the Ubuntu packages that the should be installed by including an Aptfile in the root directory of your Swift application. Each line in the Aptfile should contain a valid Ubuntu package name. For instance, if your application has a dependency on the jsonbot package, then your Aptfile should look like this:

$ cat Aptfile

Installing closed source dependencies

For those accessing private or enterprise host respositories, the IBM Cloud buildpack for Swift now works with the Swift Package Manager to build these dependencies. To leverage this capability, add a .ssh folder in the root of the application. This directory will need to contain the SSH keys needed to access the dependencies, as well as a config file referencing the keys. The example below shows the config and Package.swift files, respectively, which use the same SSH key to access private and public repositories in enterprise and standard GitHub accounts:

$ cat config
# GitHub.IBM.com - Enterprise Host, Account Key
Host github.ibm.com
    HostName github.ibm.com
    User git
    IdentityFile ~/.ssh/ssh_key

# GitHub.com - Private Repo, Account Key
Host github.com
    HostName github.com
    User git
    IdentityFile ~/.ssh/ssh_key

You should use the git protocol in your Package.swift for those dependencies that are private or stored in an enterprise solution (e.g. GitHub Enterprise) as shown below. If you use the https protocol instead, then the buildpack will not be able to clone those dependencies.

$ cat Package.swift
dependencies: [
    .Package(url: "git@github.ibm.com:Org1/repo1.git", majorVersion: 1, minor: 0),
    .Package(url: "git@github.ibm.com:Org1/repo2.git", majorVersion: 1, minor: 0),
    .Package(url: "git@github.com:Org2/repo3.git", majorVersion: 0, minor: 0),

This approach works for both SSH account keys and deployment keys. For the example below, three keys are used - two deployment keys for the enterprise GitHub, and one account key for the standard one.

$ cat config
# GitHub Enterprise - repo1 deployment key
Host enterprise1
    HostName github.ibm.com
    User git
    IdentityFile ~/.ssh/githubEnterprise_key1

# GitHub Enterprise - repo2 deployment key
Host enterprise2
    HostName github.ibm.com
    User git
    IdentityFile ~/.ssh/githubEnterprise_key2

# GitHub.com - Private Repo, Account Key
Host github.com
    HostName github.com
    User git
    IdentityFile ~/.ssh/github_key
$ cat Package.swift
dependencies: [
    .Package(url: "git@enterprise1:Org1/repo1.git", majorVersion: 1, minor: 0),
    .Package(url: "git@enterprise2:Org1/repo2.git", majorVersion: 1, minor: 0),
    .Package(url: "git@github.com:Org2/repo3.git", majorVersion: 0, minor: 0),

Additional compiler flags

To specify additional compiler flags for the execution of the swift build command, you can include a .swift-build-options-linux file. For example, in order to leverage the system package libmysqlclient-dev in a Swift application, you'd need an additional compiler flag:

$ cat .swift-build-options-linux
-Xswiftc -DNOJSON

When leveraging the PostgreSQL system library libpq-dev, the following contents should be added to the .swift-build-options-linux file:

$ cat .swift-build-options-linux
-Xcc -I/usr/include/postgresql

If you need to specify the path to header files for a system package installed by the buildpack, you can use the following:

-Xcc -I$BUILD_DIR/.apt/usr/include/<path to header files>


Previous versions of this buildpack provided the libdispatch binaries for Swift development builds prior to 2016-08-23. However, current and future versions of this buildpack will not provide those binaries. Users should upgrade their applications to Swift 3.0, which already includes the libdispatch binaries.

Caching of the .build directory

Following the release of Swift 3.1, the IBM Cloud buildpack for Swift caches the contents of the .build folder to speed up the provisioning of your application the next time you execute the ibmcloud app push command. If you'd prefer not to use this caching mechanism, you can disable it by executing the following command:

ibmcloud app env-set <app_name> SWIFT_BUILD_DIR_CACHE false
ibmcloud app restage <app_name>

If at some point, you'd like to re-enable caching of the .build folder, you can do so by executing:

ibmcloud app env-set <app_name> SWIFT_BUILD_DIR_CACHE true
ibmcloud app restage <app_name>

Note that if at some point you change the contents of your Package.swift or Package.resolved (or Package.pins for older versions of Swift) file, the buildpack will automatically refetch the dependencies and update the cache accordingly. Also, if you do not initially push a Package.resolved file along with your application and you are using Swift 4.0 (or a later version), a new Package.resolved file will be generated. It is recommended that you always push a Package.resolved file along with your application (if using Swift 4.0 or later).


If the buildpack preparation or compilation steps are failing, you can enable some debugging using the following command:

ibmcloud app env-set <app_name> BP_DEBUG true

To deactivate:

ibmcoud app env-unset <app_name> BP_DEBUG

Installing Personal Package Archives

The IBM Cloud buildpack for Swift does not support the installation of Personal Package Archives (PPAs). If your application requires the installation of one or more PPAs, we recommend using a different mechanism other than the IBM Cloud buildpack for Swift for provisioning your application to the IBM Cloud. For instance, you could use Docker and Kubernetes to provision your Swift application to the IBM Cloud (in your Dockerfile, you would add the instructions for installing any necessary PPAs).

Admin tasks

To install this buildpack:

wget https://github.com/IBM-Swift/swift-buildpack/releases/download/2.0.20/buildpack_swift_v2.0.20-20190401-2122.zip
ibmcloud cf create-buildpack swift_buildpack buildpack_swift_v2.0.20-20190401-2122.zip <position>

Position is a positive integer, sets priority, and is sorted from lowest to highest when listed using the ibmcloud cf buildpacks command.

And to update it:

wget https://github.com/IBM-Swift/swift-buildpack/releases/download/2.0.20/buildpack_swift_v2.0.20-20190401-2122.zip
ibmcloud cf update-buildpack swift_buildpack -p buildpack_swift_v2.0.20-20190401-2122.zip

For more details on installing buildpacks, see Adding buildpacks to Cloud Foundry.


The buildpack zip file provided in each release is built using the manifest.yml file:

BUNDLE_GEMFILE=cf.Gemfile bundle install
BUNDLE_GEMFILE=cf.Gemfile bundle exec buildpack-packager --cached --use-custom-manifest manifest.yml

For details on packaging buildpacks, see buildpack-packager.