class Vagrant::Util::Subprocess
Execute a command in a subprocess, gathering the results and exit status.
This class also allows you to read the data as it is outputted from the subprocess in real time, by simply passing a block to the execute method.
Public Class Methods
Convenience method for executing a method.
# File lib/vagrant/util/subprocess.rb, line 21 def self.execute(*command, &block) new(*command).execute(&block) end
# File lib/vagrant/util/subprocess.rb, line 25 def initialize(*command) @options = command.last.is_a?(Hash) ? command.pop : {} @command = command.dup @command[0] = Which.which(@command[0]) if !File.file?(@command[0]) if !@command[0] raise Errors::CommandUnavailableWindows, file: command[0] if Platform.windows? raise Errors::CommandUnavailable, file: command[0] end @logger = Log4r::Logger.new("vagrant::util::subprocess") end
Public Instance Methods
Start the process
@return [Result]
# File lib/vagrant/util/subprocess.rb, line 57 def execute # Get the timeout, if we have one timeout = @options[:timeout] # Get the working directory workdir = @options[:workdir] || Dir.pwd # Get what we're interested in being notified about notify = @options[:notify] || [] notify = [notify] if !notify.is_a?(Array) if notify.empty? && block_given? # If a block is given, subscribers must be given, otherwise the # block is never called. This is usually NOT what you want, so this # is an error. message = "A list of notify subscriptions must be given if a block is given" raise ArgumentError, message end # Let's get some more useful booleans that we access a lot so # we're not constantly calling an `include` check notify_table = {} notify_table[:stderr] = notify.include?(:stderr) notify_table[:stdout] = notify.include?(:stdout) notify_stdin = notify.include?(:stdin) # Build the ChildProcess @logger.info("Starting process: #{@command.inspect}") @process = process = ChildProcess.build(*@command) # Create the pipes so we can read the output in real time as # we execute the command. stdout, stdout_writer = ::IO.pipe stderr, stderr_writer = ::IO.pipe process.io.stdout = stdout_writer process.io.stderr = stderr_writer process.duplex = true process.leader = true if @options[:detach] process.detach = true if @options[:detach] # Special installer-related things if Vagrant.in_installer? installer_dir = Vagrant.installer_embedded_dir.to_s.downcase # If we're in an installer on Mac and we're executing a command # in the installer context, then force DYLD_LIBRARY_PATH to look # at our libs first. if Platform.darwin? if @command[0].downcase.include?(installer_dir) @logger.info("Command in the installer. Specifying DYLD_LIBRARY_PATH...") process.environment["DYLD_LIBRARY_PATH"] = "#{installer_dir}/lib:#{ENV["DYLD_LIBRARY_PATH"]}" else @logger.debug("Command not in installer, not touching env vars.") end if File.setuid?(@command[0]) || File.setgid?(@command[0]) @logger.info("Command is setuid/setgid, clearing DYLD_LIBRARY_PATH") process.environment["DYLD_LIBRARY_PATH"] = "" end end # If the command that is being run is not inside the installer, reset # the original environment - this is required for shelling out to # other subprocesses that depend on environment variables (like Ruby # and $GEM_PATH for example) internal = [installer_dir, Vagrant.user_data_path.to_s.downcase]. any? { |path| @command[0].downcase.include?(path) } if !internal @logger.info("Command not in installer, restoring original environment...") jailbreak(process.environment) end # If running within an AppImage and calling external executable. When # executable is external set the LD_LIBRARY_PATH to host values. if ENV["VAGRANT_APPIMAGE"] embed_path = Pathname.new(Vagrant.installer_embedded_dir).expand_path.to_s exec_path = Pathname.new(@command[0]).expand_path.to_s if !exec_path.start_with?(embed_path) && ENV["VAGRANT_APPIMAGE_HOST_LD_LIBRARY_PATH"] @logger.info("Detected AppImage environment and request to external binary. Updating library path.") @logger.debug("Setting LD_LIBRARY_PATH to #{ENV["VAGRANT_APPIMAGE_HOST_LD_LIBRARY_PATH"]}") process.environment["LD_LIBRARY_PATH"] = ENV["VAGRANT_APPIMAGE_HOST_LD_LIBRARY_PATH"].to_s end end else @logger.info("Vagrant not running in installer, restoring original environment...") jailbreak(process.environment) end # Set the environment on the process if we must if @options[:env] @options[:env].each do |k, v| process.environment[k] = v end end # Start the process begin SafeChdir.safe_chdir(workdir) do process.start end rescue ChildProcess::LaunchError => ex # Raise our own version of the error so that users of the class # don't need to be aware of ChildProcess raise LaunchError.new(ex.message) end # If running with the detach option, no need to capture IO or # ensure program exists. if @options[:detach] return end # Make sure the stdin does not buffer process.io.stdin.sync = true if RUBY_PLATFORM != "java" # On Java, we have to close after. See down the method... # Otherwise, we close the writers right here, since we're # not on the writing side. stdout_writer.close stderr_writer.close end # Create a dictionary to store all the output we see. io_data = { stdout: "", stderr: "" } # Record the start time for timeout purposes start_time = Time.now.to_i open_readers = [stdout, stderr] open_writers = notify_stdin ? [process.io.stdin] : [] @logger.debug("Selecting on IO") while true results = ::IO.select(open_readers, open_writers, nil, 0.1) results ||= [] readers = results[0] writers = results[1] # Check if we have exceeded our timeout raise TimeoutExceeded, process.pid if timeout && (Time.now.to_i - start_time) > timeout # Check the readers to see if they're ready if readers && !readers.empty? readers.each do |r| # Read from the IO object data = IO.read_until_block(r) # We don't need to do anything if the data is empty next if data.empty? io_name = r == stdout ? :stdout : :stderr @logger.trace("#{io_name}: #{data.chomp}") io_data[io_name] += data yield io_name, data if block_given? && notify_table[io_name] end end # Break out if the process exited. We have to do this before # attempting to write to stdin otherwise we'll get a broken pipe # error. break if process.exited? # Check the writers to see if they're ready, and notify any listeners if writers && !writers.empty? && block_given? yield :stdin, process.io.stdin # if the callback closed stdin, we should remove it, because # IO.select() will throw if called with a closed io. if process.io.stdin.closed? open_writers = [] end end end # Wait for the process to end. begin remaining = (timeout || 32000) - (Time.now.to_i - start_time) remaining = 0 if remaining < 0 @logger.debug("Waiting for process to exit. Remaining to timeout: #{remaining}") process.poll_for_exit(remaining) rescue ChildProcess::TimeoutError raise TimeoutExceeded, process.pid end @logger.debug("Exit status: #{process.exit_code}") # Read the final output data, since it is possible we missed a small # amount of text between the time we last read data and when the # process exited. [stdout, stderr].each do |io| # Read the extra data, ignoring if there isn't any extra_data = IO.read_until_block(io) next if extra_data == "" # Log it out and accumulate io_name = io == stdout ? :stdout : :stderr io_data[io_name] += extra_data @logger.trace("#{io_name}: #{extra_data.chomp}") # Yield to any listeners any remaining data yield io_name, extra_data if block_given? && notify_table[io_name] end if RUBY_PLATFORM == "java" # On JRuby, we need to close the writers after the process, # for some reason. See GH-711. stdout_writer.close stderr_writer.close end # Return an exit status container return Result.new(process.exit_code, io_data[:stdout], io_data[:stderr]) ensure if process && process.alive? && !@options[:detach] # Make sure no matter what happens, the process exits process.stop(2) end end
@return [TrueClass, FalseClass] subprocess is currently running
# File lib/vagrant/util/subprocess.rb, line 38 def running? !!(@process && @process.alive?) end
Stop the subprocess if running
@return [TrueClass] FalseClass] true if process was running and stopped
# File lib/vagrant/util/subprocess.rb, line 45 def stop if @process && @process.alive? @process.stop true else false end end
Private Instance Methods
This is, quite possibly, the saddest function in all of Vagrant
.
If a user is running Vagrant
via Bundler
(but not via the official installer), we want to reset to the “original” environment so that when shelling out to other Ruby processes (specifically), the original environment is restored. This is super important for things like rbenv and chruby, who rely on environment variables to locate gems, but Bundler
stomps on those environment variables like an angry T-Rex after watching Jurassic Park 2 and realizing they replaced you with CGI.
If a user is running in Vagrant
via the official installer, BUT trying to execute a subprocess outside of the installer, we want to reset to the “original” environment. In this case, the Vagrant
installer actually knows what the original environment was and replaces it completely.
Finally, we reset any Bundler-specific environment variables, since the subprocess being called could, itself, be Bundler
. And Bundler
does not behave very nicely in these circumstances.
This function was added in Vagrant
1.7.3, but there is a failsafe because the author doesn’t trust himself that this functionality won’t break existing assumptions, so users can specify ‘VAGRANT_SKIP_SUBPROCESS_JAILBREAK` and none of the above will happen.
This function modifies the given hash in place!
@return [nil]
# File lib/vagrant/util/subprocess.rb, line 336 def jailbreak(env = {}) return if ENV.key?("VAGRANT_SKIP_SUBPROCESS_JAILBREAK") if defined?(::Bundler) && defined?(::Bundler::ORIGINAL_ENV) env.replace(::Bundler::ORIGINAL_ENV) end env.merge!(Vagrant.original_env) # Bundler does this, so I guess we should as well, since I think it # other subprocesses that use Bundler will reload it env["MANPATH"] = ENV["BUNDLE_ORIG_MANPATH"] # Replace all current environment BUNDLE_ variables to nil ENV.each do |k,_| env[k] = nil if k[0,7] == "BUNDLE_" end # If RUBYOPT was set, unset it with Bundler if ENV.key?("RUBYOPT") env["RUBYOPT"] = ENV["RUBYOPT"].sub("-rbundler/setup", "") end nil end