Class: RightGit::Shell::Default

Inherits:
Object
  • Object
show all
Includes:
Interface, RightSupport::Ruby::EasySingleton
Defined in:
lib/right_git/shell/default.rb

Overview

Default shell singleton implementation.

Instance Method Summary collapse

Instance Method Details

#clear_env_vars(names) { ... } ⇒ TrueClass

Clears (set-to-nil) the given list of environment variables while executing the given block.

Parameters:

  • names (Array) —

    of variables to clear

Yields:

  • called with environment cleared

Returns:

  • (TrueClass) —

    always true



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# File 'lib/right_git/shell/default.rb', line 236

def clear_env_vars(names, &block)
  save_vars = {}
  names.each do |k|
    k = k.to_s
    save_vars[k] = ENV[k]
    ENV[k] = nil
  end
  begin
    yield
  ensure
    names.each do |k|
      k = k.to_s
      ENV[k] = save_vars[k]
    end
  end
  true
end

#configure_executioner(executioner, options) ⇒ Proc

Encapsulates the given executioner with child-process-modifying behavior based on options. Builds the executioner as a series of callbacks.

Parameters:

  • executioner (Proc) —

    to configure

  • options (Hash) —

    for execution

Returns:

  • (Proc) —

    configured executioner



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# File 'lib/right_git/shell/default.rb', line 173

def configure_executioner(executioner, options)
  # set specific environment variables, if requested.
  sev = options[:set_env_vars]
  if (sev && !sev.empty?)
    executioner = lambda do |e|
      lambda { set_env_vars(sev) { e.call } }
    end.call(executioner)
  end

  # clear specific environment variables, if requested.
  cev = options[:clear_env_vars]
  if (cev && !cev.empty?)
    executioner = lambda do |e|
      lambda { clear_env_vars(cev) { e.call } }
    end.call(executioner)
  end

  # working directory.
  if directory = options[:directory]
    executioner = lambda do |e, d|
      lambda { ::Dir.chdir(d) { e.call } }
    end.call(executioner, directory)
  end
  executioner
end

#default_logger ⇒ Object

Delegates to the RightGit class logger.



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# File 'lib/right_git/shell/default.rb', line 39

def default_logger
  ::RightGit::Git::Repository.logger
end

#execute(cmd, options = {}) ⇒ Object

Implements execute interface.



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# File 'lib/right_git/shell/default.rb', line 44

def execute(cmd, options = {})
  options = {
    :directory => nil,
    :outstream => nil,
    :raise_on_failure => true,
    :set_env_vars => nil,
    :clear_env_vars => nil,
    :logger => default_logger,
    :timeout => nil,
    :keep_alive_interval => nil,
    :keep_alive_timeout => nil
  }.merge(options)

  outstream = options[:outstream]
  logger = options[:logger]

  if keep_alive_interval = options[:keep_alive_interval]
    keep_alive_wake_time = ::Time.now + keep_alive_interval
  else
    keep_alive_wake_time = nil
  end
  if keep_alive_timeout = options[:keep_alive_timeout]
    unless keep_alive_interval
      raise ::ArgumentError,
            ':keep_alive_interval is required when using :keep_alive_timeout'
    end
    keep_alive_stop_time = ::Time.now + keep_alive_timeout
  else
    keep_alive_stop_time = nil
  end

  # build initial popener.
  exitstatus = nil
  popener = lambda do |output|
    output.sync = true
    loop do
      # note stdout remains selectable after process dies.
      if (::IO.select([output], nil, nil, 0.1) rescue nil)
        if data = output.gets
          if outstream
            outstream << data
          else
            data = data.strip
            unless data.empty?
              logger.info(data)

              # reset keep alive timer whenever we have normal output.
              if keep_alive_wake_time
                keep_alive_wake_time = ::Time.now + keep_alive_interval
              end
            end
          end
        else
          break
        end
      elsif keep_alive_wake_time
        now = ::Time.now
        if keep_alive_stop_time && now >= keep_alive_stop_time
          keep_alive_wake_time = nil
        elsif now >= keep_alive_wake_time
          # keep-alives go to logger, not the outstream, if any.
          logger.info('.')
          keep_alive_wake_time = now + keep_alive_interval
        end
        now = nil
      end
    end
  end

  # timeout optionally wraps popener. the timeout must happen inside of the
  # IO.popen block or else it has no good effect.
  if timeout = options[:timeout]
    popener = lambda do |p|
      lambda do |o|
        ::Timeout.timeout(timeout) { p.call(o) }
      end
    end.call(popener)
  end

  # build initial executioner in terms of popener.
  executioner = lambda do
    logger.info("+ #{cmd}")
    error_msg = nil
    ::IO.popen("#{cmd} 2>&1", 'r') do |output|
      begin
        popener.call(output)
      rescue ::EOFError
        # done
      rescue ::Timeout::Error
        # kill still-running process or else popen's ensure will hang.
        ::Process.kill('KILL', output.pid)

        # intentionally not reading last data as that could still block
        # due to a child of created process inheriting stdout.
        error_msg = "Execution timed out after #{options[:timeout]} seconds."
      end
    end

    # note that a killed process may exit 0 under Windows.
    exitstatus = $?.exitstatus
    if 0 == exitstatus && error_msg
      exitstatus = 1
    end
    if (exitstatus != 0 && options[:raise_on_failure])
      error_msg ||= "Execution failed with exitstatus #{exitstatus}"
      raise ShellError, error_msg
    end
  end

  # configure executioner (by options) and then invoke executioner.
  configure_executioner(executioner, options).call

  return exitstatus
end

#output_for(cmd, options = {}) ⇒ Object

Implements output_for interface.



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# File 'lib/right_git/shell/default.rb', line 160

def output_for(cmd, options = {})
  output = StringIO.new
  execute(cmd, options.merge(:outstream => output))
  output.string
end

#set_env_vars(variables) { ... } ⇒ TrueClass

Sets the given list of environment variables while executing the given block.

Parameters

Yield

Return

Parameters:

  • variables (Hash) —

    to set

Yields:

  • called with environment set

Returns:

  • (TrueClass) —

    always true



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# File 'lib/right_git/shell/default.rb', line 210

def set_env_vars(variables)
  save_vars = {}
  variables.each do |k, v|
    k = k.to_s
    save_vars[k] = ENV[k]
    ENV[k] = v.nil? ? v : v.to_s
  end
  begin
    yield
  ensure
    variables.each_key do |k|
      k = k.to_s
      ENV[k] = save_vars[k]
    end
  end
  true
end