How to Use the Command 'fastlane' (with examples)

Fastlane is an open-source continuous delivery tool primarily used for automating tasks related to building and releasing mobile applications. It facilitates various processes in app development, including building and deploying iOS and Android apps, code signing, testing, and managing dependencies. By integrating with existing development workflows, Fastlane can save developers considerable time and effort, ultimately making the app release process more efficient and reliable.

Use case 1: Build and sign the iOS application in the current directory

Code:

fastlane run build_app

Motivation:

Building and signing an iOS application is an essential step in the app development cycle, particularly when preparing the app for release or distribution. The process involves compiling the app’s source code into a binary file and then digitally signing it, ensuring its authenticity and integrity. Using Fastlane’s build_app action simplifies this process by automating it, thus minimizing the chances of human error and saving developers from tedious manual steps.

Explanation:

In this command, the fastlane run build_app command is a predefined action in Fastlane’s toolbox specifically designed for building iOS applications. This action automatically detects the Xcode project in the current directory and triggers a series of tasks, including compiling, linking, and packaging the app. Moreover, it handles code signing using the provisioning profiles and certificates specified in the Fastlane configuration files.

Example output:

[16:22:44]: ------------------------------------------------
[16:22:44]: --- Step: build_app ---
[16:22:44]: ------------------------------------------------
[16:22:46]: $ xcodebuild -workspace MyApp.xcworkspace -scheme MyApp -configuration Release
[16:27:01]: ▸ Building MyApp/Release [1/1] - Compiling MyApp.m
[16:27:05]: ▸ Processing Info.plist
...
[16:27:58]: Successfully built and signed MyApp.ipa

Use case 2: Run pod install for the project in the current directory

Code:

fastlane run cocoapods

Motivation:

In iOS development, CocoaPods is a widely-used dependency manager that simplifies incorporating third-party libraries into projects. The pod install command resolves dependencies specified in the Podfile, downloads the required libraries, and integrates them into Xcode projects. Automating this step using Fastlane ensures that dependencies are consistently updated and installed, reducing setup complexity, especially during CI/CD workflows.

Explanation:

The command fastlane run cocoapods invokes a Fastlane action that executes the pod install command for the current directory’s iOS project. This command reads the Podfile, fetches any necessary libraries, and generates an Xcode workspace with the dependencies linked. Using this Fastlane action ensures that the step is consistently executed, aligning dependency versions across different development machines or build servers.

Example output:

[16:30:10]: ------------------------------------------------
[16:30:10]: --- Step: cocoapods ---
[16:30:10]: ------------------------------------------------
[16:30:10]: $ pod install
[16:30:11]: Analyzing dependencies
[16:30:13]: Downloading dependencies
[16:30:21]: Installing Alamofire (5.4.3)
[16:30:24]: Generating Pods project
[16:30:29]: Integrating client project
[16:30:31]: Pod installation complete! There are 8 dependencies from the Podfile and 9 total pods installed.

Use case 3: Delete the derived data from Xcode

Code:

fastlane run clear_derived_data

Motivation:

Derived data in Xcode contains build artifacts, cache files, and other temporary data generated during app development. Over time, this data may accumulate significantly, occupying disk space and potentially causing build issues due to stale or corrupted cache files. Using Fastlane to clear derived data ensures that developers can quickly resolve build problems and free up space without manually navigating through the file system.

Explanation:

The command fastlane run clear_derived_data utilizes a Fastlane action that automatically locates and deletes the derived data directory associated with Xcode. By invoking this command, developers can rest assured that unnecessary build files are removed, ensuring a fresh environment for subsequent builds and reducing potential issues arising from outdated cached data.

Example output:

[16:33:50]: -------------------------------------------
[16:33:50]: --- Step: clear_derived_data ---
[16:33:50]: -------------------------------------------
[16:33:50]: Deleting Xcode Derived Data at: ~/Library/Developer/Xcode/DerivedData
[16:33:51]: Derived data deleted successfully!

Use case 4: Remove the cache for pods

Code:

fastlane run clean_cocoapods_cache

Motivation:

The CocoaPods cache stores previously downloaded libraries to improve efficiency during future installs. However, over time, this cache may grow excessively large or store outdated versions of libraries, leading to inconsistencies. Clearing the CocoaPods cache using Fastlane ensures that the project uses the latest dependencies and prevents build configuration issues caused by stale information.

Explanation:

The command fastlane run clean_cocoapods_cache executes a Fastlane action that identifies and removes all cached files associated with CocoaPods in the system. By cleaning this cache, developers can ensure a fresh installation of dependencies, which is especially useful when encountering dependency conflicts or corrupt installations that require resetting dependency states.

Example output:

[16:37:20]: -------------------------------------------
[16:37:20]: --- Step: clean_cocoapods_cache ---
[16:37:20]: -------------------------------------------
[16:37:20]: Deleting CocoaPods cache...
[16:37:25]: CocoaPods cache cleared successfully!

Conclusion:

Fastlane is a powerful tool for automating tedious tasks in mobile app development, enabling developers to focus more on coding and innovation rather than repetitive processes. By providing straightforward commands for building applications, managing dependencies, and handling derived data and cache, Fastlane proves to be an indispensable asset in increasing the efficiency and reliability of development workflows.