Add EnvManager

lib/fastlane/plugin/wpmreleasetoolkit/env_manager/env_manager.rb

@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require 'dotenv'
+# TODO: It would be nice to decouple this from Fastlane.
+# To give a good UX in the current use case, however, it's best to access the Fastlane UI methods directly.
+require 'fastlane'
+
+# Manages loading of environment variables from a .env and accessing them in a user-friendly way.
+class EnvManager
+  @env_path = nil
+  @env_example_path = nil
+  @print_error_lambda = nil
+
+  # Set up by loading the .env file with the given name.
+  #
+  # TODO: We could go one step and guess the name based on the repo URL.
+  def self.set_up(
+    env_file_name:,
+    env_file_folder: File.join(Dir.home, '.a8c-apps'),
+    example_env_file_path: 'fastlane/example.env',
+    print_error_lambda: ->(message) { FastlaneCore::UI.user_error!(message) }
+  )
+    @env_path = File.join(env_file_folder, env_file_name)
+    @env_example_path = example_env_file_path
+    @print_error_lambda = print_error_lambda
+
+    # We don't check for @env_path to exist here
+    Dotenv.load(@env_path)
+  end
+
+  # Use this instead of getting values from `ENV` directly. It will throw an error if the requested value is missing or empty.
+  def self.get_required_env!(key)
+    unless ENV.key?(key)
+      message = "Environment variable '#{key}' is not set."
+
+      if running_on_ci?
+        @print_error_lambda.call(message)
+      elsif File.exist?(@env_path)
+        @print_error_lambda.call("#{message} Consider adding it to #{@env_path}.")
+      else
+        env_file_dir = File.dirname(@env_path)
+        env_file_name = File.basename(@env_path)
+
+        @print_error_lambda.call <<~MSG
+          #{env_file_name} not found in #{env_file_dir} while looking for env var #{key}.
+
+          Please copy #{@env_example_path} to #{@env_path} and fill in the value for #{key}.
+
+          mkdir -p #{env_file_dir} && cp #{@env_example_path} #{@env_path}
+        MSG
+      end
+    end
+
+    value = ENV.fetch(key)
+
+    UI.user_error!("Env var for key #{key} is set but empty. Please set a value for #{key}.") if value.to_s.empty?
+
+    value
+  end
+
+  # Use this to ensure all env vars a lane requires are set.
+  #
+  # The best place to call this is at the start of a lane, to fail early.
+  def self.require_env_vars!(*keys)
+    keys.each { |key| get_required_env!(key) }
+  end
+
+  def self.running_on_ci?
+    ENV['CI'] == 'true'
+  end
+end