[zzylol]

Replace asap-precompute-rs with the Rust OTAP engine collector

Why

asap-precompute-rs/ in this repository is a stale Rust mirror of the Go
precompute runtime: a CollectorPlan decoder, a control channel, frame identity
for full and delta frames, a snapshot cache and an OTAP plugin lifecycle that no
running collector uses. The Rust collector that actually runs lives in
ProjectASAP/ASAPCollector-public: an otel-arrow OTAP dataflow engine with ASAP
nodes linked in. The SDK and the sink are moving to Rust as well, so this
repository should carry the working Rust collector instead of the mirror.

What

• asap-precompute-rs/ is replaced by a copy of ASAPCollector-public
  asap-precompute-rs/ at commit cfd3dde. The two repositories stay
  independent; the source commit is recorded in the crate README and in the
  commit message.
• The crate depends on asap_sketchlib main (branch, no rev pin; Cargo.lock
  records a05b35c) instead of the 60101c6 pin.
• KLL retention code says "tumbling window" (width W) instead of "pane".
• The CollectorPlan fixture moves to asap-precompute-go/testdata/, so the Go
  CollectorPlan test no longer reads files from the Rust crate. Three developer
  docs now name the Go consumer and the new fixture path.
• The Go processor (asapedgeprocessor, asap-precompute-go) is unchanged.

Removed with the old mirror (control plane or replaced by the engine nodes):

Removed	Replaced by / reason
src/collector_plan.rs, tests/collector_plan.rs, tests/fixtures/collector_plan_v1.json	CollectorPlan is control plane; the Go decoder and its moved fixture remain
src/control_channel.rs	control plane, not in this collector
src/frame_identity.rs, src/snapshot_cache.rs	the collector emits full-state envelopes only, so there are no delta frames to identify or rebase
src/adapter.rs, src/otap/plugin.rs, src/otap/lifecycle.rs	the local::Processor<OtapPdata> node in src/otap/processor.rs
src/otap/decode.rs, src/otap/encode.rs, src/otap/records.rs	src/otap/codec.rs (MetricsView over envelopes, decode_each)
src/sampling.rs	no sampling in this collector yet
tests/api_surface.rs, tests/otap_codec.rs, tests/otap_lifecycle.rs	tests/otap_pipeline_e2e.rs, tests/kll_windows.rs, tests/runtime.rs and unit tests

How

1. Move the CollectorPlan fixture into asap-precompute-go (Go test stays
   self-contained).
2. Replace the crate directory with the public repository's copy at cfd3dde.
3. Update the docs that pointed at the Rust CollectorPlan consumer or fixture.
4. Track asap_sketchlib main. The collector compiled unchanged against
   a05b35c:
   • it never read DDSketch sum/min/max, so nothing had to be removed when
     sketchlib dropped them (DDSketch is now kind 0x05 0x01);
   • it does not use Bloom, Space-Saving, CountSketch-with-L2, HLL-HIP or the
     capability table, whose wire and naming changes are in this range;
   • HLL stays Ertl-MLE (kind 0x01 0x02); CMS, CMS-with-heap, CountSketch and
     KLL kinds are unchanged.
     Only the DDSketch wrapper's kind comment and the README dependency note
     change.
5. Rename pane to tumbling window in kll_windows and its callers, tests,
   README and sample config comments. No config keys change.

Key code interfaces

• asap-collector --config <pipeline.yaml|json>: the upstream
  otel_dataflow/v1 controller with these ASAP nodes registered through
  linkme:
  • urn:asap:processor:asap_sketches (src/otap/processor.rs)
  • urn:asap:processor:window_merge
  • urn:asap:processor:sketch_detector
  • urn:asap:processor:heavy_hitter_accuracy
  • urn:asap:processor:{exact_branch,exact_merge,exact_detector,raw_sink}
  • urn:asap:receiver:scenario_generator
• otap::codec::decode_each(pdata, |&Observation| ..) and
  encode_envelopes_to_pdata(&[SketchEnvelope]): OTAP metrics to and from
  observations and envelopes.
• precompute::Precompute (observe, observe_envelope, tick, drain,
  update_config) and SketchObserver.
• kll_windows::KllWindowStore: new(config, window_width, retention),
  merge_window, query, quantile_over_time, retained_windows; renamed
  from merge_pane / retained_panes.

Major algorithm changes

Compared with the old mirror:

• Output is always full ASAPv1 state per tumbling window. There are no deltas,
  no frame identity and no snapshot cache.
• Ingest is content-routed. A Summary point that carries sketch.envelope is
  merged as a sketch. A Gauge or Sum point is one scalar observation. Histogram
  and ExponentialHistogram points are counted and skipped.
• A tumbling window closes as soon as a point's event time passes its end.
• KLL can retain W-wide tumbling windows and answer aligned ranges by merging
  them (sliding output, window_slide).

Before

• The asap-precompute-rs mirror had a CollectorPlan, a control channel,
  delta frames and an OTAP plugin lifecycle that no deployed collector runs.
• It pinned asap_sketchlib 60101c6.
• The Go CollectorPlan test read its fixture from the Rust crate.

After

• asap-precompute-rs is the running Rust OTAP collector from
  ASAPCollector-public at cfd3dde, on asap_sketchlib main a05b35c.
• The Go CollectorPlan test is self-contained.

Not changed here:

• ASAPQuery-backend main (071e9d26) does not depend on this crate. deploy/mvp-multinode/scripts/run_demo.sh still passes asap-precompute-rs as a build context to backend Dockerfiles that no longer exist on backend main; that script is already stale for the same reason and is left as is.
• No runnable pipeline file is included yet. plugins/asap_sketches/sample.toml uses an older layout; the working pipeline YAMLs live in ASAPCollector-public deploy/telemetry-functions/ and come with the end-to-end setup.

Verification

In asap-precompute-rs/:

• cargo fmt --check: clean
• cargo clippy --all-targets --all-features: no warnings
• cargo test --all-features: 143 passed, 0 failed, 1 ignored (benchmark)
  • lib: 99
  • stream bench: 6
  • kll_windows: 11
  • otap_pipeline_e2e: 1
  • runtime: 26

In asap-precompute-go/:

• go test ./... with sketchlib-go main through a local GOWORK: all
  packages ok

Smoke run of asap-collector:

• Setup: a scenario_generator -> asap_sketches -> urn:otel:exporter:console
  pipeline, with 2 s windows.
• KLL with transmit_sketch: false emits p50/p99 Gauges per http.route, with
  sketch.window_start_ms / sketch.window_end_ms attributes.
• DDSketch with transmit_sketch: true emits Summary points whose
  sketch.envelope starts ASAPv1 01 02 05 01, the new DDSketch kind.