Using the 'carthage' Command for Dependency Management (with examples)

Carthage is a widely-used dependency management tool designed specifically for Cocoa applications in macOS and iOS environments. It stands out by providing a decentralized approach to dependency management, allowing developers to leverage packages, libraries, or frameworks with minimal overhead. Whether you’re aiming to keep your dependencies up to date or manage them across multiple platforms, Carthage offers a spectrum of commands and functionalities tailored to streamline the process. Below, we explore various use cases of the carthage command, providing detailed examples and explanations.

Use Case 1: Download the Latest Version of All Dependencies and Build Them

Code:

carthage update

Motivation:

Keeping your application’s dependencies up to date ensures that your app benefits from the latest features and security patches provided by the library authors. The carthage update command is essential for maintaining an updated codebase where all dependent frameworks are at their newest public versions. This command saves the hassle of manually checking each dependency for updates and recompiling them, thereby optimizing the workflow.

Explanation:

• update: This command tells Carthage to fetch the latest versions of the libraries specified in your Cartfile, ensuring your project has the newest features and fixes.

Example Output:

*** Fetching Alamofire
*** Checking out Alamofire at "5.4.0"
*** xcodebuild output can be found in /var/folders/bq/vbqdf3yg/Carthage/Logs/Alamofire.log
*** Building scheme "Alamofire" in Alamofire.xcworkspace

Use Case 2: Update Dependencies, but Only Build for iOS

Code:

carthage update --platform ios

Motivation:

When developing an iOS application specifically, it may be unnecessary to build dependencies for other platforms like macOS, tvOS, or watchOS. The --platform ios option streamlines the build process by compiling frameworks exclusively for the iOS platform. This can reduce build time and make the process more efficient, which can be particularly beneficial when working with large projects or continuous integration pipelines.

Explanation:

• update: Similar to the previous example, this fetches the latest versions of specified dependencies.
• --platform ios: This flag restricts the build to iOS only, ensuring that the resultant build artifacts are relevant to iOS development, thus optimizing both time and storage.

Example Output:

*** Fetching Alamofire
*** Checking out Alamofire at "5.4.0"
*** xcodebuild output can be found in /var/folders/bq/vbqdf3yg/Carthage/Logs/Alamofire.log
*** Building scheme "Alamofire iOS" in Alamofire.xcworkspace

Use Case 3: Update Dependencies Without Building Them

Code:

carthage update --no-build

Motivation:

In some cases, you may wish to update the dependencies but postpone their integration or testing. For instance, during a heavy development cycle, you might want to fetch the latest libraries without immediately incorporating them through a build process. This command allows you to verify compatibility or inspect new releases without undertaking a potentially time-consuming build.

Explanation:

• update: Updates the dependencies as defined by your project’s Cartfile.
• --no-build: Prevents Carthage from building the downloaded dependencies, essentially decoupling the download phase from the build phase for more controlled dependency management.

Example Output:

*** Fetching Alamofire
*** Checking out Alamofire at "5.4.0"

Use Case 4: Download and Rebuild Current Versions of Dependencies Without Updating

Code:

carthage bootstrap

Motivation:

When you need to set up your development environment with the current dependencies as specified in your Cartfile.resolved file, and there’s no need for updates, the carthage bootstrap command is invaluable. It helps ensure your project builds consistently with the specific versions you’ve already verified and tested, maintaining stability across different setups and preventing unexpected issues from newly introduced bugs or changes in dependencies.

Explanation:

• bootstrap: Downloads and builds dependencies recorded in Cartfile.resolved, sticking to versions that have been explicitly resolved and confirmed earlier, rather than fetching new ones.

Example Output:

*** Checking out Alamofire at "5.3.0"
*** xcodebuild output can be found in /var/folders/bq/vbqdf3yg/Carthage/Logs/Alamofire.log
*** Building scheme "Alamofire" in Alamofire.xcodeproj

Use Case 5: Rebuild a Specific Dependency

Code:

carthage build dependency

Motivation:

There are instances when only a specific dependency needs to be rebuilt, such as when modifications have been made to a library’s configuration or when dealing with platform-specific issues. By rebuilding a specific framework, developers can save time and resources, as it circumvents the need to rebuild every dependency.

Explanation:

• build dependency: The build command is used to compile the specified dependency. Replace “dependency” with the actual name of the library you want to rebuild.

Example output:

*** xcodebuild output can be found in /var/folders/bq/vbqdf3yg/Carthage/Logs/Alamofire.log
*** Building scheme "Alamofire" in Alamofire.xcodeproj

Conclusion

Carthage provides a powerful set of tools for managing dependencies within Cocoa projects. These varied use cases highlight its flexibility and the distinct advantages it provides in maintaining, updating, and building project dependencies efficiently. As applications grow in complexity, leveraging such tools can significantly enhance development productivity while ensuring stability and compatibility within your project’s ecosystem.