feat: per-script Rhai sandbox overrides with admin ceiling

Adds optional per-script overrides for the six Rhai sandbox knobs
(max_operations, max_string_size, max_array_size, max_map_size,
max_call_levels, max_expr_depth). The executor merges its defaults
with each script's overrides on every call; the manager validates
overrides against an admin-set ceiling at write time, so the
executor trusts whatever is stored.

Storage chose JSONB on the existing scripts table over six new
columns: lets future knobs land as code-only changes, keeps the
sparse common case (most scripts override nothing) cheap to store
and serialize, and matches how the manager + executor pass the
config across the wire.

  * 0002_sandbox.sql — ALTER TABLE scripts ADD COLUMN sandbox
    JSONB NOT NULL DEFAULT '{}'
  * shared::ScriptSandbox — six Option<u64> fields with
    deny_unknown_fields so typos surface as 422
  * Script.sandbox + ExecRequest.sandbox_overrides — typed end
    to end; cluster mode just serializes the same struct
  * executor-core::Limits::with_overrides — field-by-field
    replacement; tests cover the override actually tightening
    the live engine
  * manager-core::SandboxCeiling — built-in conservative
    defaults (10M ops, 1 MiB strings, 100k array/map, 128
    call/expr depth); env vars override per knob, invalid
    values warn-and-skip rather than blocking boot
  * manager-core admin API — POST/PUT accept `sandbox`; values
    above the ceiling return 422 with the specific field +
    requested + ceiling; absent or `{}` keeps platform defaults
  * picloud all-in-one — wires SandboxCeiling::from_env() into
    AdminState
  * memory_limit_mb stays in the schema, marked v1.3+ advisory
    (no enforcement until OS-level isolation lands with
    cluster-mode executors)

Verified live through Caddy:
  * /version reports schema 2, product 0.3.0
  * Script with max_operations: 500 → 507 on a 10k-iteration loop
  * Same script after PUT raising to 1M → succeeds, returns 10000
  * POST with max_operations: 1_000_000_000 → 422 (exceeds ceiling)

Tests:
  * 13 executor-core unit tests (added 2 for override semantics)
  * 20 integration tests (added 6 for sandbox CRUD + ceiling +
    unknown-field rejection + executor honoring overrides)
  * default cargo test --workspace stays green (integration tests
    remain #[ignore]'d until DATABASE_URL is set)

Bumps:
  * schema 1 → 2
  * product 0.2.0 → 0.3.0
  * SDK unchanged (scripts see nothing new)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/manager-core/src/api.rs

@@ -11,12 +11,15 @@ use axum::{
     routing::get,
     Json, Router,
 };
-use picloud_shared::{ExecutionLog, Script, ScriptId, ScriptValidator, ValidationError};
+use picloud_shared::{
+    ExecutionLog, Script, ScriptId, ScriptSandbox, ScriptValidator, ValidationError,
+};
 use serde::Deserialize;
 
 use crate::repo::{
     ExecutionLogRepository, NewScript, ScriptPatch, ScriptRepository, ScriptRepositoryError,
 };
+use crate::sandbox::{CeilingError, SandboxCeiling};
 
 /// State shared by control-plane handlers. Separates concerns so the
 /// manager can validate at upload time without depending on the
@@ -25,6 +28,7 @@ pub struct AdminState<R, L> {
     pub repo: Arc<R>,
     pub logs: Arc<L>,
     pub validator: Arc<dyn ScriptValidator>,
+    pub sandbox_ceiling: SandboxCeiling,
 }
 
 impl<R, L> Clone for AdminState<R, L> {
@@ -33,6 +37,7 @@ impl<R, L> Clone for AdminState<R, L> {
             repo: self.repo.clone(),
             logs: self.logs.clone(),
             validator: self.validator.clone(),
+            sandbox_ceiling: self.sandbox_ceiling,
         }
     }
 }
@@ -70,6 +75,11 @@ pub struct CreateScriptRequest {
     pub source: String,
     pub timeout_seconds: Option<i32>,
     pub memory_limit_mb: Option<i32>,
+    /// Sandbox overrides; absent or empty `{}` means "use platform
+    /// defaults". Each non-null field is checked against the admin
+    /// ceiling at write time.
+    #[serde(default)]
+    pub sandbox: ScriptSandbox,
 }
 
 #[derive(Debug, Deserialize)]
@@ -83,6 +93,10 @@ pub struct UpdateScriptRequest {
     pub source: Option<String>,
     pub timeout_seconds: Option<i32>,
     pub memory_limit_mb: Option<i32>,
+    /// `Some(sandbox)` replaces the stored overrides wholesale (use
+    /// `Some(ScriptSandbox::empty())` to clear them). Absent leaves
+    /// the stored value unchanged.
+    pub sandbox: Option<ScriptSandbox>,
 }
 
 #[allow(clippy::option_option)]
@@ -120,6 +134,7 @@ async fn create_script<R: ScriptRepository, L: ExecutionLogRepository>(
     Json(input): Json<CreateScriptRequest>,
 ) -> Result<(StatusCode, Json<Script>), ApiError> {
     state.validator.validate(&input.source)?;
+    state.sandbox_ceiling.check(&input.sandbox)?;
     let created = state
         .repo
         .create(NewScript {
@@ -128,6 +143,11 @@ async fn create_script<R: ScriptRepository, L: ExecutionLogRepository>(
             source: input.source,
             timeout_seconds: input.timeout_seconds,
             memory_limit_mb: input.memory_limit_mb,
+            sandbox: if input.sandbox.is_empty() {
+                None
+            } else {
+                Some(input.sandbox)
+            },
         })
         .await?;
     Ok((StatusCode::CREATED, Json(created)))
@@ -141,6 +161,9 @@ async fn update_script<R: ScriptRepository, L: ExecutionLogRepository>(
     if let Some(src) = input.source.as_deref() {
         state.validator.validate(src)?;
     }
+    if let Some(sb) = input.sandbox.as_ref() {
+        state.sandbox_ceiling.check(sb)?;
+    }
     let updated = state
         .repo
         .update(
@@ -151,6 +174,7 @@ async fn update_script<R: ScriptRepository, L: ExecutionLogRepository>(
                 source: input.source,
                 timeout_seconds: input.timeout_seconds,
                 memory_limit_mb: input.memory_limit_mb,
+                sandbox: input.sandbox,
             },
         )
         .await?;
@@ -205,6 +229,9 @@ pub enum ApiError {
     #[error("invalid script: {0}")]
     Invalid(#[from] ValidationError),
 
+    #[error("{0}")]
+    Ceiling(#[from] CeilingError),
+
     #[error("repository error: {0}")]
     Repo(#[from] ScriptRepositoryError),
 }
@@ -214,7 +241,9 @@ impl IntoResponse for ApiError {
         let (status, message) = match &self {
             Self::NotFound(_) => (StatusCode::NOT_FOUND, self.to_string()),
             Self::Conflict(_) => (StatusCode::CONFLICT, self.to_string()),
-            Self::Invalid(_) => (StatusCode::UNPROCESSABLE_ENTITY, self.to_string()),
+            Self::Invalid(_) | Self::Ceiling(_) => {
+                (StatusCode::UNPROCESSABLE_ENTITY, self.to_string())
+            }
             Self::Repo(ScriptRepositoryError::NotFound(_)) => {
                 (StatusCode::NOT_FOUND, self.to_string())
             }

crates/manager-core/src/lib.rs

@@ -8,6 +8,7 @@ pub mod api;
 pub mod log_sink;
 pub mod migrations;
 pub mod repo;
+pub mod sandbox;
 pub mod scheduler;
 
 pub use api::{admin_router, AdminState};
@@ -16,3 +17,4 @@ pub use repo::{
     ExecutionLogRepository, NewScript, PostgresExecutionLogRepository, PostgresScriptRepository,
     RepoResolver, ScriptPatch, ScriptRepository, ScriptRepositoryError,
 };
+pub use sandbox::{CeilingError, SandboxCeiling};

crates/manager-core/src/repo.rs

@@ -2,7 +2,7 @@ use std::collections::BTreeMap;
 
 use async_trait::async_trait;
 use picloud_orchestrator_core::{ResolverError, ScriptResolver};
-use picloud_shared::{ExecutionLog, ExecutionStatus, RequestId, Script, ScriptId};
+use picloud_shared::{ExecutionLog, ExecutionStatus, RequestId, Script, ScriptId, ScriptSandbox};
 use sqlx::PgPool;
 
 #[derive(Debug, thiserror::Error)]
@@ -40,6 +40,9 @@ pub struct NewScript {
     pub source: String,
     pub timeout_seconds: Option<i32>,
     pub memory_limit_mb: Option<i32>,
+    /// Sandbox overrides; `None` means store an empty object (use
+    /// platform defaults at exec time).
+    pub sandbox: Option<ScriptSandbox>,
 }
 
 /// Inbound shape for update. `None` fields are left untouched.
@@ -50,6 +53,9 @@ pub struct ScriptPatch {
     pub source: Option<String>,
     pub timeout_seconds: Option<i32>,
     pub memory_limit_mb: Option<i32>,
+    /// `Some(sandbox)` replaces the stored overrides wholesale (including
+    /// `Some(empty)` to clear them); `None` leaves them untouched.
+    pub sandbox: Option<ScriptSandbox>,
 }
 
 pub struct PostgresScriptRepository {
@@ -73,7 +79,7 @@ impl ScriptRepository for PostgresScriptRepository {
     async fn get(&self, id: ScriptId) -> Result<Option<Script>, ScriptRepositoryError> {
         let row = sqlx::query_as::<_, ScriptRow>(
             "SELECT id, name, description, version, source, \
-                    timeout_seconds, memory_limit_mb, created_at, updated_at \
+                    timeout_seconds, memory_limit_mb, sandbox, created_at, updated_at \
              FROM scripts WHERE id = $1",
         )
         .bind(id.into_inner())
@@ -85,7 +91,7 @@ impl ScriptRepository for PostgresScriptRepository {
     async fn list(&self) -> Result<Vec<Script>, ScriptRepositoryError> {
         let rows = sqlx::query_as::<_, ScriptRow>(
             "SELECT id, name, description, version, source, \
-                    timeout_seconds, memory_limit_mb, created_at, updated_at \
+                    timeout_seconds, memory_limit_mb, sandbox, created_at, updated_at \
              FROM scripts ORDER BY name",
         )
         .fetch_all(&self.pool)
@@ -94,17 +100,22 @@ impl ScriptRepository for PostgresScriptRepository {
     }
 
     async fn create(&self, input: NewScript) -> Result<Script, ScriptRepositoryError> {
+        let sandbox_json = serde_json::to_value(input.sandbox.unwrap_or_default())
+            .unwrap_or_else(|_| serde_json::json!({}));
         let res = sqlx::query_as::<_, ScriptRow>(
-            "INSERT INTO scripts (name, description, source, timeout_seconds, memory_limit_mb) \
-             VALUES ($1, $2, $3, COALESCE($4, 30), COALESCE($5, 256)) \
+            "INSERT INTO scripts ( \
+                name, description, source, \
+                timeout_seconds, memory_limit_mb, sandbox \
+             ) VALUES ($1, $2, $3, COALESCE($4, 30), COALESCE($5, 256), $6) \
              RETURNING id, name, description, version, source, \
-                       timeout_seconds, memory_limit_mb, created_at, updated_at",
+                       timeout_seconds, memory_limit_mb, sandbox, created_at, updated_at",
         )
         .bind(&input.name)
         .bind(input.description.as_deref())
         .bind(&input.source)
         .bind(input.timeout_seconds)
         .bind(input.memory_limit_mb)
+        .bind(sandbox_json)
         .fetch_one(&self.pool)
         .await;
 
@@ -128,6 +139,13 @@ impl ScriptRepository for PostgresScriptRepository {
         // COALESCE-based partial update: `NULL` parameters leave columns
         // untouched. Description is double-Optioned so callers can
         // explicitly set it to NULL (Some(None)) vs leave it alone (None).
+        // Sandbox is replaced wholesale when present; per-field merging
+        // happens in the API layer (clearer semantics for a "PUT a new
+        // sandbox config" call).
+        let sandbox_json = patch
+            .sandbox
+            .as_ref()
+            .map(|s| serde_json::to_value(s).unwrap_or_else(|_| serde_json::json!({})));
         let row = sqlx::query_as::<_, ScriptRow>(
             "UPDATE scripts SET \
                 name = COALESCE($2, name), \
@@ -135,11 +153,12 @@ impl ScriptRepository for PostgresScriptRepository {
                 source = COALESCE($5, source), \
                 timeout_seconds = COALESCE($6, timeout_seconds), \
                 memory_limit_mb = COALESCE($7, memory_limit_mb), \
+                sandbox = COALESCE($8, sandbox), \
                 version = version + 1, \
                 updated_at = NOW() \
              WHERE id = $1 \
              RETURNING id, name, description, version, source, \
-                       timeout_seconds, memory_limit_mb, created_at, updated_at",
+                       timeout_seconds, memory_limit_mb, sandbox, created_at, updated_at",
         )
         .bind(id.into_inner())
         .bind(patch.name.as_deref())
@@ -148,6 +167,7 @@ impl ScriptRepository for PostgresScriptRepository {
         .bind(patch.source.as_deref())
         .bind(patch.timeout_seconds)
         .bind(patch.memory_limit_mb)
+        .bind(sandbox_json)
         .fetch_optional(&self.pool)
         .await?;
 
@@ -177,12 +197,18 @@ struct ScriptRow {
     source: String,
     timeout_seconds: i32,
     memory_limit_mb: i32,
+    sandbox: serde_json::Value,
     created_at: chrono::DateTime<chrono::Utc>,
     updated_at: chrono::DateTime<chrono::Utc>,
 }
 
 impl From<ScriptRow> for Script {
     fn from(r: ScriptRow) -> Self {
+        // Tolerate stale rows whose sandbox column predates a future
+        // schema migration: unknown fields are rejected by serde, so
+        // fall back to an empty ScriptSandbox rather than poisoning a
+        // list response.
+        let sandbox = serde_json::from_value(r.sandbox).unwrap_or_default();
         Self {
             id: r.id.into(),
             name: r.name,
@@ -191,6 +217,7 @@ impl From<ScriptRow> for Script {
             source: r.source,
             timeout_seconds: u32::try_from(r.timeout_seconds).unwrap_or(30),
             memory_limit_mb: u32::try_from(r.memory_limit_mb).unwrap_or(256),
+            sandbox,
             created_at: r.created_at,
             updated_at: r.updated_at,
         }

crates/manager-core/src/sandbox.rs

@@ -0,0 +1,103 @@
+//! Admin-set ceiling for per-script sandbox overrides.
+//!
+//! The orchestrator-core's default `Limits` is what scripts get when they
+//! don't override. The ceiling here is the per-field maximum that a
+//! script's override is allowed to request. Validation runs at write
+//! time so the executor can trust whatever's stored.
+
+use std::env;
+
+use picloud_shared::ScriptSandbox;
+use thiserror::Error;
+
+/// Maximum allowed value per sandbox knob. Loaded from env vars at
+/// startup (with conservative built-in defaults). A `None` field means
+/// "unbounded" — only useful if the operator explicitly clears the
+/// ceiling for a given knob (it must still fit `u64`).
+#[derive(Debug, Clone, Copy)]
+pub struct SandboxCeiling {
+    pub max_operations: u64,
+    pub max_string_size: u64,
+    pub max_array_size: u64,
+    pub max_map_size: u64,
+    pub max_call_levels: u64,
+    pub max_expr_depth: u64,
+}
+
+impl SandboxCeiling {
+    /// Conservative built-in ceiling. Matches the executor's defaults —
+    /// scripts can request anything between zero and this, but no
+    /// higher. Operators can widen via env vars (see `from_env`).
+    #[must_use]
+    pub const fn conservative() -> Self {
+        Self {
+            max_operations: 10_000_000,
+            max_string_size: 1024 * 1024, // 1 MiB
+            max_array_size: 100_000,
+            max_map_size: 100_000,
+            max_call_levels: 128,
+            max_expr_depth: 128,
+        }
+    }
+
+    /// Read overrides from env vars, falling back to `conservative()`
+    /// for any unset knob. Invalid values are ignored with a warning
+    /// (we'd rather start with the conservative default than refuse to
+    /// boot on a typo).
+    #[must_use]
+    pub fn from_env() -> Self {
+        let mut c = Self::conservative();
+        macro_rules! load {
+            ($field:ident, $key:expr) => {
+                if let Ok(v) = env::var($key) {
+                    match v.parse::<u64>() {
+                        Ok(n) => c.$field = n,
+                        Err(e) => tracing::warn!(env = $key, error = %e, "ignoring invalid sandbox ceiling value"),
+                    }
+                }
+            };
+        }
+        load!(max_operations, "PICLOUD_SANDBOX_MAX_OPERATIONS");
+        load!(max_string_size, "PICLOUD_SANDBOX_MAX_STRING_SIZE");
+        load!(max_array_size, "PICLOUD_SANDBOX_MAX_ARRAY_SIZE");
+        load!(max_map_size, "PICLOUD_SANDBOX_MAX_MAP_SIZE");
+        load!(max_call_levels, "PICLOUD_SANDBOX_MAX_CALL_LEVELS");
+        load!(max_expr_depth, "PICLOUD_SANDBOX_MAX_EXPR_DEPTH");
+        c
+    }
+
+    /// Returns `Err` if any override exceeds the ceiling on the same
+    /// field. Empty overrides (`ScriptSandbox::empty()`) always pass.
+    pub fn check(&self, s: &ScriptSandbox) -> Result<(), CeilingError> {
+        check_field("max_operations", s.max_operations, self.max_operations)?;
+        check_field("max_string_size", s.max_string_size, self.max_string_size)?;
+        check_field("max_array_size", s.max_array_size, self.max_array_size)?;
+        check_field("max_map_size", s.max_map_size, self.max_map_size)?;
+        check_field("max_call_levels", s.max_call_levels, self.max_call_levels)?;
+        check_field("max_expr_depth", s.max_expr_depth, self.max_expr_depth)?;
+        Ok(())
+    }
+}
+
+fn check_field(name: &'static str, value: Option<u64>, ceiling: u64) -> Result<(), CeilingError> {
+    if let Some(v) = value {
+        if v > ceiling {
+            return Err(CeilingError::Exceeded {
+                field: name,
+                requested: v,
+                ceiling,
+            });
+        }
+    }
+    Ok(())
+}
+
+#[derive(Debug, Error, Clone)]
+pub enum CeilingError {
+    #[error("sandbox override `{field}` = {requested} exceeds admin ceiling of {ceiling}")]
+    Exceeded {
+        field: &'static str,
+        requested: u64,
+        ceiling: u64,
+    },
+}