App_Environment_Variables

App Environment Variables

Setting environment variables on the project and reading from them via Xcode.

Xcode

Recent updates I believe from Xcode 12.5 gives an option for xcode-build-cli to be able to import the Environment variables of the host environment.
Which leads to good opportunities towards getting xcode work in tandem with various CI/CD providers to have different SWITCH | A/B Behavior on dev environments locally or remote servers running the build commands.

iOS Implementation

On iOS you can read the environment variable keys | values using this code snippet.

if let envV = ProcessInfo.processInfo.environment["IS_CI_SERVER"] {
	print("The environment variable \(envV)")													   
}

xcode build Env variables

Sarunw | setup iOS Environments develop | staging | production

Issues

While importing the environment variables, sometimes your host terminal environment variables aren't being imported properly. But if you edit the main scheme of the app and append the Environment variables to that scheme it would be able to properly import that value.

But what if you want set it via CLI on your host and then xcode test or xcode-build-test CLI should appropriately get that file. You would have to specify the value as in Xcode Scheme GUI.

"IS_CI_SERVER" = ${IS_CI_SERVER}
"IS_CI_SERVER" = $(IS_CI_SERVER)

Xcode 13 Release notes

Maybe the syntax has been updated towards using $(ENV_KEY) but its such a mess to get Xcode GUI + .env direct source reference that at that point its better to just provide the xcode cli environment variables

More source comment for my run tests on xcode 16.3.0

xcodebuild now supports passing certain environment variables to test runner processes. In the environment where xcodebuild is invoked, prefix any variable with TEST_RUNNER_ to pass that variable (with the prefix stripped) to XCTest test runner processes. For example, running env TEST_RUNNER_Foo=Bar xcodebuild test ... causes the environment variable Foo=Bar to be set in the test runner’s environment. (74104870)

Additionally, existing variables may be modified using the special token __CURRENT_VALUE__ to represent their current value. For example, TEST_RUNNER_Foo=__CURRENT_VALUE__:Bar appends the string :Bar to any existing value of Foo. Note that only test runner processes receive these environment variables. To set them in apps targeted by UI tests, customize the XCUIApplication.launchEnvironment dictionary prior to launching the app.

Export .env to Xcode CLI ProcessInfo

# Example script for the Run Script Phase (assuming .env is in project root)
    # This script will set environment variables that can be accessed by your app
    while IFS='=' read -r key value; do
        if [[ ! -z "$key" && ! "$key" =~ ^# ]]; then
            echo "Setting environment variable: $key=$value"
            export "$key=$value"
        fi
    done < "${SRCROOT}/.env"

xcConfig source env

- name: Add variables to xcconfig
  run: |
    echo "API_KEY = ${{ secrets.MY_API_KEY }}" >> MyProject.xcconfig
    echo "BUILD_NUMBER = ${{ github.run_number }}" >> MyProject.xcconfig
    echo "CUSTOM_SETTING = ${{ vars.MY_CUSTOM_VAR }}" >> MyProject.xcconfig

Links

https://medium.com/tauk-blog/passing-arguments-and-environment-variables-to-xctests-ebb60e55cece

https://stackoverflow.com/questions/27500940/how-to-let-the-app-know-if-its-running-unit-tests-in-a-pure-swift-project

https://blog.kulman.sk/reading-environment-variables-from-unit-tests/