Issue #19078 has been updated by matz (Yukihiro Matsumoto). This proposal contains 4 features: (1) fiber[key]/fiber[key]=val - accepted. (2) fiber.storage => hash - accepted (3) fiber.storage=hash - should be experimental (4) Fiber.new(...,storage: hash|true|false|nil) - accepted, but true/false should be experimental The feature (3) can be bigger side effect to clear third-party storage, so we need some experiment. The feature (4) with true/false are hard to read the intention (true to inherit with dup, false to inherit without dup), so we need experiment here as well. Matz. ---------------------------------------- Feature #19078: Introduce `Fiber#storage` for inheritable fiber-scoped variables. https://bugs.ruby-lang.org/issues/19078#change-100370 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal * Assignee: ioquatix (Samuel Williams) ---------------------------------------- Pull Request: https://github.com/ruby/ruby/pull/6612 This is an evolution of the previous ideas: - https://bugs.ruby-lang.org/issues/19058 - https://bugs.ruby-lang.org/issues/19062 This PR introduces fiber scoped variables, and is a solution for problems like <https://github.com/ioquatix/ioquatix/discussions/17>. The main interface is: ```ruby Fiber[key] = value Fiber[key] # => value ``` The variables are scoped (local to) a fiber and inherited into child fibers and threads. ```ruby Fiber[:request_id] = SecureRandom.hex(16) Fiber.new do p Fiber[:request_id] # prints the above request id end ``` The fiber scoped variables are stored and can be accessed: ```ruby Fiber.current.storage # => returns a Hash (copy) of the internal storage. Fiber.current.storage= # => assigns a Hash (copy) to the internal storage. ``` Fiber itself has one new keyword argument: ``` Fiber.new(..., storage: hash, false, undef, nil) ``` This can control how the fiber variables are setup in a child context. To minimise the performance overhead of some of the implementation choices, we are also simultaneously implementing <https://bugs.ruby-lang.org/issues/19077>. ## Examples ### Request loop ```ruby Thread.new do while request = queue.pop Fiber.new(storage: {id: SecureRandom.hex(16)}) do handle_request.call(request) end end end ``` OR ```ruby Thread.new do while request = queue.pop Fiber.current.storage = {id: SecureRandom.hex(16)} handle_request.call(request) end end ``` -- https://bugs.ruby-lang.org/