Class: Akita::HarLogger::WriterThread

Inherits:
Object
  • Object
show all
Defined in:
lib/akita/har_logger/writer_thread.rb

Overview

A thread that consumes HarEntry objects from a queue and writes them to a file.

Params:

out_file_name

the name of the HAR file to be produced.

entry_queue

the queue from which to consume HAR entries.

Instance Method Summary collapse

Constructor Details

#initialize(out_file_name, entry_queue) ⇒ WriterThread

Returns a new instance of WriterThread.



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# File 'lib/akita/har_logger/writer_thread.rb', line 12

def initialize(out_file_name, entry_queue)
  # This mutex is used to ensure the entire output is written before the
  # application shuts down.
  shutdown_mutex = Mutex.new

  Thread.new do
    Rails.logger.debug "AKITA: About to acquire shutdown mutex "\
                       "#{shutdown_mutex} for file #{out_file_name} "\
                       "in writer thread #{Thread.current}. "\
                       "Self-owned? #{shutdown_mutex.owned?}"
    shutdown_mutex.synchronize {
      begin
        Rails.logger.debug "AKITA: Acquired shutdown mutex "\
                           "#{shutdown_mutex} for file "\
                           "#{out_file_name} in writer thread "\
                           "#{Thread.current}."
        File.open(out_file_name, 'w') { |f|
          # Produce a preamble.
          f.write "            {\n              \"log\": {\n                \"version\": \"1.2\",\n                \"creator\": {\n                  \"name\": \"Akita HAR logger for Ruby\",\n                  \"version\": \"1.0.0\"\n                },\n                \"entries\": [\n          EOF\n\n          first_entry = true\n\n          loop do\n            entry = entry_queue.pop\n            if entry == nil then break end\n\n            # Emit comma separator if needed.\n            f.puts (first_entry ? '' : ',')\n            first_entry = false\n\n            # Emit the dequeued entry.\n            f.write JSON.generate(entry)\n          end\n\n          # Produce the epilogue.\n          f.write <<~EOF\n\n                ]\n              }\n            }\n          EOF\n        }\n      ensure\n        Rails.logger.debug \"AKITA: About to release shutdown mutex \"\\\n                           \"\#{shutdown_mutex} for file \"\\\n                           \"\#{out_file_name} in writer thread \"\\\n                           \"\#{Thread.current}.\"\n      end\n    }\n  end\n\n  # Finish outputting the HAR file when the application shuts down.\n  at_exit do\n    # Signal to the consumer that this is the end of the entry stream and\n    # wait for the consumer to terminate.\n    entry_queue << nil\n    Rails.logger.debug \"AKITA: About to acquire shutdown mutex \"\\\n                       \"\#{shutdown_mutex} for file \#{out_file_name} \"\\\n                       \"while shutting down in \#{Thread.current}. \"\\\n                       \"Self-owned? \#{shutdown_mutex.owned?}\"\n    shutdown_mutex.synchronize {\n      Rails.logger.debug \"AKITA: Acquired shutdown mutex \"\\\n                         \"\#{shutdown_mutex} for file \#{out_file_name} \"\\\n                         \"while shutting down in \#{Thread.current}.\"\n      Rails.logger.debug \"AKITA: About to release shutdown mutex \"\\\n                         \"\#{shutdown_mutex} for file \#{out_file_name} \"\\\n                         \"while shutting down in \#{Thread.current}.\"\n    }\n  end\nend\n".chomp