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Stirling-PDF/app/saas
ConnorYohandGitHub 3807cdfbc6 PAYG: process tracking + shadow charging engine (PR B-1) (#6477)
> 📌 **Stacked on
[#6464](https://github.com/Stirling-Tools/Stirling-PDF/pull/6464)**
(lineage primitives, still in review). #6469 has merged so its commits
are no longer in this PR's diff. Once #6464 merges, a final rebase
collapses the lineage-primitives commits out of this diff too — leaving
only the B-1 work.

## What this is

Process tracking + shadow charging engine. Bundles PR-I7 service half
with the non-filter piece of PR-I7a so the pieces ship together — none
of them is useful in isolation.

**Review focus:** the new files in:
- \`app/saas/src/main/java/stirling/software/saas/payg/job/\`
(\`JobService\`, \`JobContext\`, \`JoinOrOpenResult\`,
\`StaleJobCloser\`)
- \`app/saas/src/main/java/stirling/software/saas/payg/charge/\`
(\`JobChargeService\`, \`ChargeContext\`, \`ChargeOutcome\`,
\`JobInput\`)
-
\`app/saas/src/main/java/stirling/software/saas/payg/lineage/LineagePruneScheduler.java\`
- their tests

The 8 files inherited from #6464 (lineage primitives) are unchanged from
there — they ride along in this diff until #6464 lands.

The remaining work for shadow-in-staging is the ingress/egress filter
that wires controllers into this engine — that's PR B-2.

## Scope

### \`JobService\` — persistence + lineage policy

- **\`joinOrOpen\`** — the multi-input "any-match-joins, newest wins"
rule. Hash every input via the lineage detector; if any matches an open
process in the workflow window, attach to the one with the freshest
\`lastStepAt\`. Step-limit overflow on the matched job spawns a fresh
process; the new job's input signatures are still recorded so
\`mostRecentMatchWins\` routes future calls forward.
- **\`recordOutput\`** — post-tool-success path. Records OUTPUT
signatures so the next call that takes this file as input
lineage-matches into the same process.
- **\`appendStep\`** — audit-trail step row written after a tool
completes.
- **\`close\`** — idempotent; safe to call from multiple paths
(explicit, FE on-unload, scheduler). Returns the same row on re-close,
no state mutation.
- **\`findStale\` / \`closeStale\`** — workflow-window-based stale
closure used by the scheduler.

### \`JobChargeService\` — the orchestrator (shadow variant)

\`openProcess\` resolves the effective policy via
\`PricingPolicyService\` (now in main via #6469), derives the step-limit
for the current \`JobSource\` (with a defensive fallback if the policy
is missing an entry), delegates to \`JobService.joinOrOpen\`, and on
OPENED runs the \`DocumentClassifier\` + writes a \`payg_shadow_charge\`
row. Applies the policy-level \`minChargeUnits\` floor per design § 3.4.

Shadow variant only — never debits the ledger, never posts a Stripe
meter event. The real-charging follow-up reuses the same orchestration
and swaps the side-effect. \`legacyCreditsCharged\` on the shadow row
stays \`0\` until the legacy \`CreditService\` is wired in (PR B-2),
where the comparison becomes meaningful.

### Schedulers (both plain \`@Scheduled\`)

- **\`StaleJobCloser\`** — fixed-rate 60 s. Closes \`OPEN\` jobs idle
past the workflow window. API users never have to call close explicitly
— this is the safety net.
- **\`LineagePruneScheduler\`** — hourly cron, retention 1 h. Deletes
\`job_artifact_hash\` rows older than the retention window.
- **No \`@SchedulerLock\` / no \`shedlock\` table** — consistent with
the 5 existing unguarded \`@Scheduled\` tasks in \`:saas\`
(\`CreditResetScheduler\` and friends, none of which are guarded today).
Cluster-correctness across all 7 saas schedulers is tracked in design §
9 as a separate focused cleanup. Underlying operations are idempotent —
duplicate firings on multi-pod would be wasted DB load, not data
corruption.

### Records (call-shape glue for PR B-2's filter)

- \`JobContext\` / \`JoinOrOpenResult\` — input/output for
\`JobService\`.
- \`ChargeContext\` / \`ChargeOutcome\` — input/output for
\`JobChargeService\`.
- \`JobInput\` — paired \`(MultipartFile, materialised Path)\` so the
upcoming ingress filter can pass both views without re-materialising.

## Tests

**26 new, all green.**

- 14 × \`JobServiceTest\` — no-match → opens new, single-match → joins
existing, multi-input any-match-joins, multi-match newest-wins (older
job never even looked up), step-limit hit spawns fresh job (and original
\`stepCount\` is NOT mutated), empty inputs reject, stale-signature
handling, recordOutput delegation, close idempotency, closeStale,
appendStep persistence.
- 7 × \`JobChargeServiceTest\` — JOINED skips classifier + shadow write
entirely, OPENED writes shadow row + classifies (single + multi file
paths), \`minChargeUnits\` floor applied, step-limit resolved
per-\`JobSource\` from policy, missing source entry falls back to
conservative default of 10.
- 2 × \`StaleJobCloserTest\`, 3 × \`LineagePruneSchedulerTest\` —
scheduler-wiring smoke + constructor-validation tests.

\`ENABLE_SAAS=true ./gradlew :saas:test\` — BUILD SUCCESSFUL.

## What's not in this PR (lands in PR B-2)

- **Tool ingress/egress servlet filter.** The highest-risk piece —
materialises the request body into a \`JobInput\`, calls
\`JobChargeService.openProcess\` from every \`@AutoJobPostMapping\`,
records OUTPUT after success. Edge cases to validate: multipart parts,
async controllers, streaming responses, errored 5xx paths, very large
files. Design decisions for the filter are being worked through in
\`notes/PAYG_FILTER_DESIGN.md\` before any code is written.
- **Wire shadow path into legacy \`CreditService\`.** Every legacy debit
writes a comparison row carrying both the PAYG would-be units and the
legacy actual credits, populating \`diffPct\`.

## Design doc

\`notes/PAYG_DESIGN.md\` — PR-I7 + PR-I7a status updated to reflect this
bundle. § 9 carries the cluster-correctness deferral note alongside the
existing LISTEN/NOTIFY trade-off note. § 7.5.1 readiness summary shows
the path now needs just **1 more PR** (the filter half + CreditService
wire-in, both bundled into PR B-2).
2026-06-04 11:09:25 +00:00
..
2026-05-21 16:05:35 +01:00
2026-05-21 16:05:35 +01:00