This is not an existing class, but documentation of the interface that Scheduler
object should comply to in order to be used as argument to Fiber.scheduler
and handle non-blocking fibers. See also the “Non-blocking fibers” section in Fiber
class docs for explanations of some concepts.
Scheduler’s behavior and usage are expected to be as follows:
When the execution in the non-blocking Fiber
reaches some blocking operation (like sleep, wait for a process, or a non-ready I/O), it calls some of the scheduler’s hook methods, listed below.
Scheduler
somehow registers what the current fiber is waiting on, and yields control to other fibers with Fiber.yield
(so the fiber would be suspended while expecting its wait to end, and other fibers in the same thread can perform)
At the end of the current thread execution, the scheduler’s method scheduler_close is called
The scheduler runs into a wait loop, checking all the blocked fibers (which it has registered on hook calls) and resuming them when the awaited resource is ready (e.g. I/O ready or sleep time elapsed).
This way concurrent execution will be achieved transparently for every individual Fiber’s code.
Scheduler
implementations are provided by gems, like Async.
Hook methods are:
io_wait
, io_read
, io_write
, io_pread
, io_pwrite
, and io_select
, io_close
(the list is expanded as Ruby developers make more methods having non-blocking calls)
When not specified otherwise, the hook implementations are mandatory: if they are not implemented, the methods trying to call hook will fail. To provide backward compatibility, in the future hooks will be optional (if they are not implemented, due to the scheduler being created for the older Ruby version, the code which needs this hook will not fail, and will just behave in a blocking fashion).
It is also strongly recommended that the scheduler implements the fiber
method, which is delegated to by Fiber.schedule
.
Sample toy implementation of the scheduler can be found in Ruby’s code, in test/fiber/scheduler.rb
An error caused by searching for a dependency that is completely unknown, i.e. has no versions available whatsoever.
An error caused by attempting to fulfil a dependency that was circular
@note This exception will be thrown if and only if a {Vertex} is added to a
{DependencyGraph} that has a {DependencyGraph::Vertex#path_to?} an existing {DependencyGraph::Vertex}
Class for representing HTTP method PATCH:
require 'net/http' uri = URI('http://example.com') hostname = uri.hostname # => "example.com" uri.path = '/posts' req = Net::HTTP::Patch.new(uri) # => #<Net::HTTP::Patch PATCH> req.body = '{"title": "foo","body": "bar","userId": 1}' req.content_type = 'application/json' res = Net::HTTP.start(hostname) do |http| http.request(req) end
Properties:
Request body: yes.
Response body: yes.
Safe: no.
Idempotent: no.
Cacheable: no.
Related:
Net::HTTP#patch
: sends PATCH
request, returns response object.
Class for representing WebDAV method PROPPATCH:
require 'net/http' uri = URI('http://example.com') hostname = uri.hostname # => "example.com" req = Net::HTTP::Proppatch.new(uri) # => #<Net::HTTP::Proppatch PROPPATCH> res = Net::HTTP.start(hostname) do |http| http.request(req) end
Related:
Net::HTTP#proppatch
: sends PROPPATCH
request, returns response object.
A FetchError
exception wraps up the various possible IO
and HTTP failures that could happen while downloading from the internet.
@!visibility private (see DependencyGraph#add_edge_no_circular
)
@!visibility private @see DependencyGraph#detach_vertex_named
Returns the real (absolute) pathname of pathname in the actual filesystem. The real pathname doesn’t contain symlinks or useless dots.
If dir_string is given, it is used as a base directory for interpreting relative pathname instead of the current directory.
The last component of the real pathname can be nonexistent.
Returns all components of the filename given in file_name except the last one (after first stripping trailing separators). The filename can be formed using both File::SEPARATOR
and File::ALT_SEPARATOR
as the separator when File::ALT_SEPARATOR
is not nil
.
File.dirname("/home/gumby/work/ruby.rb") #=> "/home/gumby/work"
If level
is given, removes the last level
components, not only one.
File.dirname("/home/gumby/work/ruby.rb", 2) #=> "/home/gumby" File.dirname("/home/gumby/work/ruby.rb", 4) #=> "/"
With string object
given, returns true
if path
is a string path leading to a directory, or to a symbolic link to a directory; false
otherwise:
File.directory?('.') # => true File.directory?('foo') # => false File.symlink('.', 'dirlink') # => 0 File.directory?('dirlink') # => true File.symlink('t,txt', 'filelink') # => 0 File.directory?('filelink') # => false
Argument path
can be an IO
object.
Returns the real (absolute) pathname of self
in the actual filesystem.
Does not contain symlinks or useless dots, ..
and .
.
The last component of the real pathname can be nonexistent.