Class: Autorespawn
- Inherits:
-
Object
- Object
- Autorespawn
- Includes:
- Hooks, Hooks::InstanceHooks
- Defined in:
- lib/autorespawn.rb,
lib/autorespawn/self.rb,
lib/autorespawn/hooks.rb,
lib/autorespawn/slave.rb,
lib/autorespawn/watch.rb,
lib/autorespawn/manager.rb,
lib/autorespawn/version.rb,
lib/autorespawn/exceptions.rb,
lib/autorespawn/program_id.rb,
lib/autorespawn/tracked_file.rb
Overview
Automatically exec’s the current program when one of the source file changes
The exec is done at very-well defined points to avoid weird state, and it is possible to define cleanup handlers beyond Ruby’s at_exit mechanism
Call this method from the entry point of your program, giving it the actual program functionality as a block. The method will exec and spawn subprocesses at will, when needed, and call the block in these subprocesses as required.
At the point of call, all of the program’s dependencies must be already required, as it is on this basis that the auto-reloading will be done
This method does NOT return
Defined Under Namespace
Modules: Hooks Classes: AlreadyRunning, FileNotFound, Manager, NotFinished, NotSlave, ProgramID, Self, Slave, TrackedFile, Watch
Constant Summary collapse
- INITIAL_STATE_FD =
"AUTORESPAWN_AUTORELOAD"
- SLAVE_RESULT_ENV =
'AUTORESPAWN_SLAVE_RESULT_FD'
- SLAVE_INITIAL_STATE_ENV =
'AUTORESPAWN_SLAVE_INITIAL_STATE_FD'
- VERSION =
"0.6.1"
Instance Attribute Summary collapse
-
#error_paths ⇒ Set<Pathname>
readonly
Set of paths that are part of an error backtrace.
-
#exceptions ⇒ Array<Exception>
readonly
Exceptions received in a #requires block or in a file required with #require.
-
#name ⇒ nil, Object
readonly
An arbitrary objcet that can be used to identify the processes/slaves.
-
#process_command_line ⇒ (Array,Hash)
readonly
The arguments that should be passed to Kernel.exec in standalone mode.
-
#program_id ⇒ ProgramID
readonly
Object currently known state of files makind this program.
-
#required_paths ⇒ Set<Pathname>
readonly
Set of paths that have been required within a #requires block or through #require.
-
#subcommands ⇒ Object
readonly
In master/slave mode, the list of subcommands that the master should spawn.
Hooks collapse
-
#at_exit {|exception| ... } ⇒ Object
Register a callback that is called after the block passed to #run has been called, but before the process gets respawned.
-
#on_exception {|exception| ... } ⇒ Object
Register a callback that is called whenever an exception is rescued by #watch_yield.
Class Method Summary collapse
- .initial_program_id ⇒ Object
-
.name ⇒ nil, Object
ID object.
- .read_child_state ⇒ Object
- .run(*command, **options, &block) ⇒ Object
- .slave? ⇒ Boolean
- .slave_result_fd ⇒ Object
Instance Method Summary collapse
-
#add_slave(*cmdline, name: nil, **spawn_options) ⇒ Object
Request that the master spawns these subcommands.
- #currently_loaded_files ⇒ Object
-
#dump_initial_state(files) ⇒ Object
Create a pipe and dump the program ID state of the current program there.
-
#exit_code(value = nil) ⇒ Object
Defines the exit code for this instance.
-
#initialize(*command, name: Autorespawn.name, track_current: false, **options) ⇒ Autorespawn
constructor
A new instance of Autorespawn.
- #perform_work(all_files, &block) ⇒ Object private
-
#require(file) ⇒ Object
Requires one file under the autorespawn supervision.
-
#run(&block) ⇒ Object
Perform the program workd and reexec it when needed.
-
#slave? ⇒ Boolean
Returns whether we have been spawned by a manager, or in standalone mode.
-
#watch_yield ⇒ Object
Call to require a bunch of files in a block and add the result to the list of watches.
Methods included from Hooks
Constructor Details
#initialize(*command, name: Autorespawn.name, track_current: false, **options) ⇒ Autorespawn
Returns a new instance of Autorespawn.
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# File 'lib/autorespawn.rb', line 135 def initialize(*command, name: Autorespawn.name, track_current: false, **) if command.empty? command = [$0, *ARGV] end @name = name @program_id = Autorespawn.initial_program_id || ProgramID.new @process_command_line = [command, ] @exceptions = Array.new @required_paths = Set.new @error_paths = Set.new @subcommands = Array.new @exit_code = 0 if track_current @required_paths = currently_loaded_files.to_set end end |
Instance Attribute Details
#error_paths ⇒ Set<Pathname> (readonly)
Set of paths that are part of an error backtrace
This is updated in #requires or #require
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# File 'lib/autorespawn.rb', line 130 def error_paths @error_paths end |
#exceptions ⇒ Array<Exception> (readonly)
Returns exceptions received in a #requires block or in a file required with #require.
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# File 'lib/autorespawn.rb', line 117 def exceptions @exceptions end |
#name ⇒ nil, Object (readonly)
An arbitrary objcet that can be used to identify the processes/slaves
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# File 'lib/autorespawn.rb', line 81 def name @name end |
#process_command_line ⇒ (Array,Hash) (readonly)
The arguments that should be passed to Kernel.exec in standalone mode
Ignored in slave mode
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# File 'lib/autorespawn.rb', line 88 def process_command_line @process_command_line end |
#program_id ⇒ ProgramID (readonly)
Returns object currently known state of files makind this program.
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# File 'lib/autorespawn.rb', line 113 def program_id @program_id end |
#required_paths ⇒ Set<Pathname> (readonly)
Set of paths that have been required within a #requires block or through #require
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# File 'lib/autorespawn.rb', line 123 def required_paths @required_paths end |
#subcommands ⇒ Object (readonly)
In master/slave mode, the list of subcommands that the master should spawn
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# File 'lib/autorespawn.rb', line 133 def subcommands @subcommands end |
Class Method Details
.initial_program_id ⇒ Object
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# File 'lib/autorespawn.rb', line 56 def self.initial_program_id @initial_program_id end |
.name ⇒ nil, Object
ID object
An arbitrary object passed to #initialize or #add_slave to identify this process.
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# File 'lib/autorespawn.rb', line 47 def self.name @name end |
.read_child_state ⇒ Object
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# File 'lib/autorespawn.rb', line 61 def self.read_child_state # Delete the envvars first, we really don't want them to leak slave_initial_state_fd = ENV.delete(SLAVE_INITIAL_STATE_ENV) slave_result_fd = ENV.delete(SLAVE_RESULT_ENV) if slave_initial_state_fd slave_initial_state_fd = Integer(slave_initial_state_fd) io = IO.for_fd(slave_initial_state_fd) size = io.read(4).unpack('L<').first @name, @initial_program_id = Marshal.load(io.read(size)) io.close end if slave_result_fd @slave_result_fd = Integer(slave_result_fd) end end |
.run(*command, **options, &block) ⇒ Object
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# File 'lib/autorespawn.rb', line 314 def self.run(*command, **, &block) new(*command, **).run(&block) end |
.slave? ⇒ Boolean
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# File 'lib/autorespawn.rb', line 53 def self.slave? !!slave_result_fd end |
.slave_result_fd ⇒ Object
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# File 'lib/autorespawn.rb', line 50 def self.slave_result_fd @slave_result_fd end |
Instance Method Details
#add_slave(*cmdline, name: nil, **spawn_options) ⇒ Object
Request that the master spawns these subcommands
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# File 'lib/autorespawn.rb', line 203 def add_slave(*cmdline, name: nil, **) subcommands << [name, cmdline, ] end |
#at_exit {|exception| ... } ⇒ Object
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# File 'lib/autorespawn.rb', line 107 define_hooks :at_respawn |
#currently_loaded_files ⇒ Object
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# File 'lib/autorespawn.rb', line 223 def currently_loaded_files $LOADED_FEATURES.map { |p| Pathname.new(p) } + caller_locations.map { |l| Pathname.new(l.absolute_path) } end |
#dump_initial_state(files) ⇒ Object
Create a pipe and dump the program ID state of the current program there
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# File 'lib/autorespawn.rb', line 209 def dump_initial_state(files) program_id = ProgramID.new files = program_id.resolve_file_list(files) program_id.register_files(files) io = Tempfile.new "autorespawn_initial_state" initial_info = Marshal.dump([name, program_id]) io.write([initial_info.size].pack("L<")) io.write(initial_info) io.flush io.rewind io end |
#exit_code(value = nil) ⇒ Object
Defines the exit code for this instance
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# File 'lib/autorespawn.rb', line 229 def exit_code(value = nil) if value @exit_code = value else @exit_code end end |
#on_exception {|exception| ... } ⇒ Object
Register a callback that is called whenever an exception is rescued by #watch_yield
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# File 'lib/autorespawn.rb', line 98 define_hooks :on_exception |
#perform_work(all_files, &block) ⇒ Object
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
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# File 'lib/autorespawn.rb', line 282 def perform_work(all_files, &block) not_tracked = all_files. find_all do |p| begin !program_id.include?(p) rescue FileNotFound end end if not_tracked.empty? && !program_id.changed? if exceptions.empty? did_yield = true watch_yield(&block) end all_files = required_paths | error_paths not_tracked = all_files. find_all do |p| begin !program_id.include?(p) rescue FileNotFound end end if !slave? && not_tracked.empty? Watch.new(program_id).wait end if did_yield run_hook :at_respawn end end all_files end |
#require(file) ⇒ Object
Requires one file under the autorespawn supervision
If the require fails, the call to run will not execute its block, instead waiting for the file(s) to change
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# File 'lib/autorespawn.rb', line 158 def require(file) watch_yield { Kernel.require file } end |
#run(&block) ⇒ Object
Perform the program workd and reexec it when needed
It is the last method you should be calling in your program, providing the program’s actual work in the block. Once the block return, the method will watch for changes and reexec’s it
Exceptions raised by the block are displayed but do not cause the watch to stop
This method does NOT return
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# File 'lib/autorespawn.rb', line 247 def run(&block) if slave? || subcommands.empty? all_files = required_paths | error_paths if block_given? all_files = perform_work(all_files, &block) end if slave? io = IO.for_fd(Autorespawn.slave_result_fd) string = Marshal.dump([subcommands, all_files]) io.write string io.flush exit exit_code else io = dump_initial_state(all_files) cmdline = process_command_line[0].dup redirect = Hash[io.fileno => io.fileno].merge(process_command_line[1]) if cmdline.last.kind_of?(Hash) redirect = redirect.merge(cmdline.pop) end Kernel.exec(Hash[SLAVE_INITIAL_STATE_ENV => "#{io.fileno}"], *cmdline, redirect) end else if block_given? raise ArgumentError, "cannot call #run with a block after using #add_slave" end manager = Manager.new subcommands.each do |name, command, | manager.add_slave(*command, name: name, **) end return manager.run end end |
#slave? ⇒ Boolean
Returns whether we have been spawned by a manager, or in standalone mode
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# File 'lib/autorespawn.rb', line 196 def slave? self.class.slave? end |
#watch_yield ⇒ Object
Call to require a bunch of files in a block and add the result to the list of watches
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# File 'lib/autorespawn.rb', line 163 def watch_yield current = currently_loaded_files new_exceptions = Array.new begin result = yield rescue Interrupt, SystemExit raise rescue Exception => e new_exceptions << e run_hook :on_exception, e exceptions << e # cross-drb exceptions are broken w.r.t. #backtrace_locations. It # returns a string in their case. Since it happens only on # exceptions that originate from the server (which means a broken # Roby codepath), let's just ignore it if !e.backtrace_locations.kind_of?(String) backtrace = e.backtrace_locations.map { |l| Pathname.new(l.absolute_path) } else STDERR.puts "Caught what appears to be a cross-drb exception, which should not happen" STDERR.puts e. STDERR.puts e.backtrace.join("\n ") backtrace = Array.new end error_paths.merge(backtrace) if e.kind_of?(LoadError) && e.path error_paths << Pathname.new(e.path) end end required_paths.merge(currently_loaded_files - current) return result, new_exceptions end |