Output Browser logs on failure for Cuprite Capybara driver

spec/support/capybara_browser_logs.rb

@@ -4,21 +4,79 @@ module Capybara::BrowserLogs
   # Capture browser logs on failed examples and output them in Progress and
   # Documentation formatters.
   class Capture
+    # Regex matching Ferrum's incoming CDP message format: "  ◀ 0.123 {json}"
+    CDP_INCOMING_MESSAGE_PATTERN = /^\s+◀\s+[\d.]+\s+(.+)$/
+
     class << self
       def after_failed_example(example)
         return unless failed?(example)
         return unless example.example_group.include?(Capybara::DSL)
         return if Capybara.page.current_url.blank?
-        return unless Capybara.page.driver.browser.respond_to?(:manage)
 
-        logs = Capybara.page.driver.browser.manage.instance_variable_get(:@bridge).log("browser")
-        example.metadata[:browser_logs] = logs
+        logs = extract_logs
+        example.metadata[:browser_logs] = logs if logs
       rescue StandardError => e
         warn "Unable to get browser logs: #{e}"
       end
 
       private
 
+      def extract_logs
+        if cuprite_driver?
+          extract_cuprite_logs
+        elsif selenium_driver?
+          extract_selenium_logs
+        end
+      end
+
+      def cuprite_driver?
+        Capybara.page.driver.is_a?(Capybara::Cuprite::Driver)
+      end
+
+      def selenium_driver?
+        Capybara.page.driver.browser.respond_to?(:manage)
+      end
+
+      def extract_selenium_logs
+        Capybara.page.driver.browser.manage.instance_variable_get(:@bridge).log("browser")
+      end
+
+      def extract_cuprite_logs
+        logger = CupriteCdpLogger.logger
+        return unless logger
+
+        logger.string.each_line.filter_map do |line|
+          match = line.match(CDP_INCOMING_MESSAGE_PATTERN)
+          next unless match
+
+          parse_console_api_called(match[1])
+        end
+      end
+
+      def parse_console_api_called(json_string)
+        data = JSON.parse(json_string)
+        return unless data["method"] == "Runtime.consoleAPICalled"
+
+        params = data["params"]
+        type = params["type"]
+        args = params["args"].map { |arg| format_cdp_arg(arg) }
+        "#{type}: #{args.join(' ')}"
+      rescue JSON::ParserError
+        nil
+      end
+
+      def format_cdp_arg(arg)
+        return arg["value"].to_s if arg.key?("value")
+
+        if (preview = arg["preview"]) && (properties = preview["properties"])
+          formatted = properties.map { |p| "#{p['name']}: #{p['value']}" }.join(", ")
+          overflow = preview["overflow"] ? ", ..." : ""
+          return "{#{formatted}#{overflow}}"
+        end
+
+        arg["description"] || arg["type"]
+      end
+
       # borrowed from capybara-screenshot code
       def failed?(example)
         return true if example.exception
@@ -59,6 +117,8 @@ module Capybara::BrowserLogs
       logs = example.metadata[:browser_logs]
         .map(&:to_s)
         .grep_v(EXCLUDE_PATTERN)
+      return if logs.empty?
+
       output.puts("  Browser logs:\n    #{logs.join("\n    ")}")
     end
   end
@@ -68,6 +128,10 @@ end
 RSpec.configure do |config|
   config.after(type: :feature) do |example|
     Capybara::BrowserLogs::Capture.after_failed_example(example)
+    if (logger = CupriteCdpLogger.logger)
+      logger.truncate(0)
+      logger.rewind
+    end
   end
 
   config.before(:suite) do

spec/support/cuprite_setup.rb

@@ -31,6 +31,12 @@
 
 require "capybara/cuprite"
 
+module CupriteCdpLogger
+  class << self
+    attr_accessor :logger
+  end
+end
+
 def headful_mode?
   ActiveRecord::Type::Boolean.new.cast(ENV.fetch("OPENPROJECT_TESTING_NO_HEADLESS", nil))
 end
@@ -80,6 +86,9 @@ def register_better_cuprite(language, name: :"better_cuprite_#{language}")
 
     options = configure_remote_chrome(options)
 
+    CupriteCdpLogger.logger = StringIO.new
+    options = options.merge(logger: CupriteCdpLogger.logger)
+
     browser_options = {
       "disable-dev-shm-usage": nil,
       "disable-gpu": nil,