feat(core): unwrap capabilities of nested request managers (#3999) - #4038
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janbuchar
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…ng for ThrottlingRequestManager (apify#3999)
…olve constructor await build and lint errors
…throttlingManager field
…r and remove redundant await in throttling_request_manager
…nt await, and update crawlee-basic API snapshot
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Closing as superseded by #4061. Thanks for your contribution! |
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…anager to fix leaky abstraction of ThrottlingRequestManager (#4061) - closes #3999 - closes #4027 - supersedes #4037 - supersedes #4038 - contributes to #4039 Worth reviewing in order — each change stands alone, with the reasoning in its own message. 1. `checkReadiness()` replaces `isEmpty()` / `isFinished()` on `IRequestLoader` and `IRequestManager`. 2. `IRequestManager.recordPacingSignal()` replaces the `SupportsDomainThrottling` capability probe. 3. The crawler builds the `sameDomainDelaySecs` throttler in its constructor, which is what puts it *inside* the tandem. 4. `sameDomainDelaySecs` goes in through `recordPacingSignal()` as a floor covering every domain, so a manager that already paces takes it instead of getting a second pacer wrapped around it. 5. `ThrottlingRequestManager`'s `inner` is optional — omitted, it opens the default queue on first use. Same feature as #4037, which is a much smaller patch on top of the lazy `inner` factory this branch already has. On #3999 this takes the first option — wrappers forward — but the objection there was that it makes `RequestManagerTandem` know throttling exists. It doesn't: pacing signals are `IRequestManager` members, so the tandem forwards a `PacingSignal` it never looks inside, and learns nothing throttling-specific. That deletes the capability-discovery problem rather than solving it, which is why the delegation interface from #4038 isn't here. One capability check did survive that — the guard refusing `sameDomainDelaySecs` over a `ThrottlingRequestManager` — and it missed a throttler behind a tandem (#discussion_r3851833671). The fourth change removes it rather than deepening it: the floor is a `PacingSignal` like any other, so whatever paces takes it wherever it sits in a composition, and a manager pacing only *some* of its domains throws rather than under-applying it. No `instanceof` left anywhere. #4039 is the shape `sameDomainDelaySecs` was producing on its own: wrapping happened at first use, by which point the tandem for a `requestList` already existed, so the pacer went outside it and a list's requests reached the queue without passing a per-domain clock. The third commit builds the pacer in the constructor instead, so those requests are routed by domain like any other. The hand-built form in #4039's reproduction is untouched — `fetchNextRequest` still takes whatever `inner` offers without checking the clocks — so #4040 is still needed. Migration notes in `docs/upgrading/upgrading_v4.md`.
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Resolves #3999
Summary
When a
ThrottlingRequestManageris wrapped inside another request manager (such asRequestManagerTandemcreated viarequestList.toTandem(throttler)),BasicCrawlerprobed capabilities via a shallowsupportsDomainThrottling(manager)check. Because outer wrappers do not directly expose rate-limit methods, domain throttling capabilities (429 backoff,robots.txtcrawl delay, stall detection) quietly stopped working.This PR introduces generic capability delegation:
DelegatingRequestManagerInterface: ExportsgetDelegatedManager()allowing wrappers to expose their inner request manager(s).RequestManagerTandem&ThrottlingRequestManagerDelegation:RequestManagerTandemimplementsgetDelegatedManager(): Promise<IRequestManager> | IRequestManagerreturning its inner manager without needing to know anything about throttling.findDomainThrottlingManager: Traverses delegating managers with an anti-recursionvisitedset to prevent circular stack overflows.BasicCrawlerOptimization: ResolvesfindDomainThrottlingManagerduring crawler setup (_init()) and caches#throttlingManagerfor O(1) zero-overhead checks.Testing
test/core/storages/throttling_request_manager.test.tsverifying direct discovery, unwrapping throughRequestManagerTandem, and anti-recursion protection for circular delegators.