#789 (partial, further tuning deferred): combining inline frame writer, buffered
frame reader, one timer per evaluation for T and T+G, slot release on the reader
before the caller resumes, a non-spinning per-connection result dispatcher, and
blocking pipe I/O on Unix (both ends) so the socket never enters the socket
engine; TerminateJobObject kill on Windows. macOS host CPU at 10k evals/s K=2:
228-240 % -> 79 % (InProcess 69 %, IPC share +10 vs budget 25); windev 153 % ->
123 % (+115, still a miss). Harness reports the "vs InProcess" share, warm-cache
worker RSS, and times kill latency from the soft-timeout answer.
#790: the worker sends LoadStarted; the compile timeout is armed then, so a load
queued behind other compiles is never killed or struck.
#788: one Error with stack per down period, rate-limited Warnings with attempt
count, one Information on recovery.
Design doc §8.2 notes + §12.2 record.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
- A self-contained Host publish (-r win-x64 --self-contained, the Windows installs) now publishes the
ScriptWorker self-contained for the same RID into script-worker/. The launcher starts its apphost
directly when runtimeconfig.json lists includedFrameworks. A framework-dependent worker (docker-dev)
keeps running through the dotnet muxer.
- docker-dev/docker-compose.script-runner.yml: OutOfProcess for the central pair's VT + Calc seams.
Live drill recorded in design §12.1 (runaway kill + quarantine, kill -9 recovery, open circuit
with /health/ready still 200, metrics).
- ScriptRunnerPerfTests (Category=Perf, opt-in via OTOPCUA_SCRIPT_PERF=1): InProcess vs OutOfProcess
at K=1/2/4. The accepted 5k evals/s/node gate passes on macOS and windev. The host-CPU, RSS and
Windows latency budget misses are tracked as #789.
- Fix: the single-flight slot is released before the awaiting caller resumes. Before, a caller that
started its next run right after the previous one returned could be refused with "previous
evaluation still running", which the seams publish as Bad.
- Fix: the worker compiles on dedicated threads, not the thread pool. A burst of cold loads starved
the heartbeat, and the host killed the shard (found on windev). Load-timeout queueing is #790.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Second P1 slice of docs/plans/2026-11-09-out-of-process-script-runner-design.md; still opt-in behind
Scripting:Runner=OutOfProcess (InProcess unchanged).
- Compiled-PE cache (design §7, §14 #8): Scripting:Worker:PeCacheDir holds <dir>/pe/<id>.pe entries authenticated
with HMAC-SHA256 under a per-node random key (<dir>/pe-cache.key, created by the host, 0600/0700 on Unix), handed to
the worker in Hello. Entry id = SHA-256(compile fingerprint + kind + source); the fingerprint covers the Roslyn
version, the Core.Scripting build (analyzer, wrapper, stack guard), the sandbox reference set and the runtime. Edited,
truncated, other-key or renamed entries are rejected, deleted and recompiled; the worker never loads unverified bytes.
Pruned by recency at startup (30 d / 50 000). ScriptEvaluator splits into CompileToImage + FromImage. Measured on
40 scripts, restart to every first result: macOS 820 ms no cache / 840 ms empty / 85 ms warm;
windev (Windows) 9.5 s / 9.4 s / 1.0 s.
- Quarantine race: WorkerConnection runs exit attribution synchronously BEFORE completing the evaluations/loads it held
(and before Exited), and the shard passes it straight to the runner — a kill strike is in place before the killed
key's slot is released.
- Supervision: a dead worker restarts by itself after its backoff; Unavailable outcomes carry ScriptRunOutcome.Recovery
(-> VirtualTagEvalResult.RetryWhen) and the VT actor / Calculation driver re-evaluate once against current inputs when
it completes. Isolation worker stops after Scripting:Worker:IsolationIdleTimeout (10 min). Keys compiling when a
worker dies are suspects too (isolation finds a poison compile and quarantines it). Startup orphan sweep by launch
marker: kills only a process whose marker's host is gone and whose pid + start time + image match.
- Crash-loop circuit (Scripting:Worker:CircuitOpenAfter, 2 min): runner Unavailable, one Error, evaluations answered
at once while shards keep retrying at the cap.
- Observability (§10): otopcua.script.runner.state, worker.up/inflight/queue_depth/heap_bytes (shard),
ipc.roundtrip + eval.duration (kind), compile{cache}, isolation.suspects, exits reason=idle. `script-runner` health
check on the ready tier, at worst Degraded (§14 #12: degraded but still ready).
Left on #780: self-contained worker publish, installer (account, pipe ACL, firewall), docker-dev live drill,
scripted-alarm seam, the §4.5 per-seam batch submit, the §8 perf harness.
Tests: SupervisionTests, PeCacheStoreTests/PeCacheWorkerTests (real workers), ScriptRunnerHealthCheckTests, VT + Calc
recovery seam tests; 14 mutations each turned their test red.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty