MechaCat02 bdcd3dc7f4 fix(executor): bound Rhai→JSON materialization to prevent anonymous OOM
The per-element Rhai sandbox caps (max_string_size 64 KiB, max_array_size /
max_map_size 10 000) do NOT bound the *materialized* size: Rhai shares strings
and arrays by Rc, so a 10 000-element array of one aliased 64 KiB string is
cheap to build (~10 000 ops, far under the 1 M op budget) yet dealiases to
~640 MiB of distinct JSON. Every Dynamic→JSON conversion deep-copies the
aliases; the HTTP response body path had NO size cap at all, and the KV/docs
value caps run only AFTER full materialization — so a handful of anonymous
requests could OOM the node (32 concurrent × ~640 MiB ≈ 20 GiB) on the stated
consumer-hardware target.

Add a byte-budgeted materializer that bails the moment the budget is exceeded,
so the transient allocation is bounded regardless of aliasing:
- bridge.rs: `dynamic_to_json_capped(value, max) -> Result<Json, JsonSizeError>`
  (charges a running budget) + `MAX_JSON_MATERIALIZE_BYTES` (16 MiB hard rail,
  far above the 256 KiB business caps). `dynamic_to_json` stays infallible for
  best-effort paths (logging) but is now internally bounded — it collapses an
  over-limit value to a marker string instead of OOMing.
- Route every user-value boundary through the fail-closed capped form: KV
  set/set_if (+ the CAS `expected`), docs create/update/find, secrets set,
  http request body, workflow input, `json::stringify`, and the HTTP RESPONSE
  body (previously the one fully-uncapped exit → now a 500). `invoke` args and
  the pubsub/queue message materializers get the same byte budget in place.
- `impl From<JsonSizeError> for Box<EvalAltResult>` so SDK sites protect
  themselves with a bare `?`.

Pinned by bridge unit tests: an aliased 10 000×64 KiB array errors on the
budget rather than materializing, and the infallible wrapper yields a marker
instead of OOMing. Workspace 914 + journeys 157/157 green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-13 21:50:16 +02:00

PiCloud

A lightweight, self-hosted, event-driven serverless compute platform. Upload a Rhai script, get an HTTP endpoint. Designed to run on a single modest server with no idle CPU cost, and to scale out to a small cluster when you need it.

Status: Phase 1 — MVP scaffolding in progress.

The authoritative design lives in serverless_cloud_blueprint.md.

Why

Existing serverless platforms are either cloud-locked, heavyweight, or both. PiCloud aims for the opposite end of the spectrum: one binary, one database, one reverse proxy — running on hardware you already own.

Architecture (one paragraph)

PiCloud splits into three logical services — manager (control plane: scripts, schedules, dashboard), orchestrator (per-node event ingress and dispatch), and executor (per-node Rhai sandbox) — each backed by a *-core Rust library. In MVP they run in a single process; in cluster mode they run as three binaries with one manager and one orchestrator + executor per node. Caddy fronts everything; PostgreSQL is the single source of truth.

See CLAUDE.md for working notes and serverless_cloud_blueprint.md for the full design.

Quick Start

Coming as scaffolding lands. For now:

# Rust toolchain (pinned via rust-toolchain.toml)
cargo check --workspace

# Run the all-in-one MVP binary (once main.rs is wired up)
cargo run -p picloud

Repository Layout

crates/
  shared/                 cross-cutting types
  executor-core/          Rhai engine + sandbox
  orchestrator-core/      event ingress, dispatch
  manager-core/           control plane
  picloud/                MVP all-in-one binary
  picloud-{manager,orchestrator,executor}/   cluster-mode binaries (skeleton)
dashboard/                SvelteKit
caddy/                    Caddyfile
docker/                   Dockerfiles
docs/
  git-workflow.md         Trunk-based workflow

Contributing

See docs/git-workflow.md for the branching and commit conventions. TL;DR: trunk-based, short-lived branches, Conventional Commits, no force-pushing main.

License

TBD.

Description
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