# Architecture Overview (High-Level)

This document is the 10-minute tour for StellaOps: what components exist, how they fit together, and what "offline-first + deterministic + evidence-linked decisions" means in practice.

For the full reference map (services, boundaries, detailed flows), see `docs/07_HIGH_LEVEL_ARCHITECTURE.md`.

## Guiding Principles

- **SBOM-first:** scan and reason over SBOMs; fall back to unpacking only when needed.
- **Deterministic replay:** the same inputs yield the same outputs (stable ordering, canonical hashing, UTC timestamps).
- **Evidence-linked decisions:** policy decisions link back to specific evidence artifacts (SBOM slices, advisory/VEX observations, reachability proofs, attestations).
- **Aggregation-not-merge:** upstream advisories and VEX are stored and exposed with provenance; conflicts are visible, not silently collapsed.
- **Offline-first:** the same workflow runs connected or air-gapped via Offline Kit snapshots and signed bundles.

## System Map (What Runs)

```
Build -> Sign -> Store -> Scan -> Decide -> Attest -> Notify/Export
```

At a high level, StellaOps is a set of services grouped by responsibility:

- **Identity and authorization:** Authority (OIDC/OAuth2, scopes/tenancy)
- **Scanning and SBOM:** Scanner WebService + Worker (facts generation)
- **Advisories:** Concelier (ingest/normalize/export vulnerability sources)
- **VEX:** Excititor + VEX Lens (VEX observations/linksets and exploration)
- **Decisioning:** Policy Engine surfaces (lattice-style explainable policy)
- **Signing and transparency:** Signer + Attestor (DSSE/in-toto and optional transparency)
- **Orchestration and delivery:** Scheduler, Notify, Export Center
- **Console:** Web UI for operators and auditors

| Tier | Services | Key responsibilities |
|------|----------|----------------------|
| **Edge / Identity** | `StellaOps.Authority` | Issues short-lived tokens (DPoP + mTLS), exposes OIDC device-code + auth-code flows, rotates JWKS. |
| **Scan & attest** | `StellaOps.Scanner` (API + Worker), `StellaOps.Signer`, `StellaOps.Attestor` | Accept SBOMs/images, drive analyzers, produce DSSE bundles, optionally log to a Rekor mirror. |
| **Evidence graph** | `StellaOps.Concelier`, `StellaOps.Excititor`, `StellaOps.Policy.Engine` | Ingest advisories/VEX, correlate linksets, run lattice policy and VEX-first decisioning. |
| **Experience** | `StellaOps.Web` (Console), `StellaOps.Cli`, `StellaOps.Notify`, `StellaOps.ExportCenter` | Operator UX, automation, notifications, and offline/mirror packaging. |
| **Data plane** | PostgreSQL, Valkey, RustFS/object storage (optional NATS JetStream) | Canonical store, counters/queues, and artifact storage with deterministic layouts. |

## Infrastructure (What Is Required)

**Required**

- **PostgreSQL:** canonical persistent store for module schemas.
- **Valkey:** Redis-compatible cache/streams and DPoP nonce store.
- **RustFS (or equivalent S3-compatible store):** object storage for artifacts, bundles, and evidence.

**Optional (deployment-dependent)**

- **NATS JetStream:** optional messaging transport in some deployments.
- **Transparency log services:** Rekor mirror (and CA services) when transparency is enabled.

## End-to-End Flow (Typical)

1. **Evidence enters** via Concelier and Excititor connectors (Aggregation-Only Contract).
2. **SBOM arrives** from CLI/CI; Scanner deduplicates layers and enqueues work.
3. **Analyzer bundle** runs inside the Worker and stores evidence in content-addressed caches.
4. **Policy Engine** merges advisories, VEX, and inventory/usage facts; emits explain traces and stable dispositions.
5. **Signer + Attestor** wrap outputs into DSSE bundles and (optionally) anchor them in a Rekor mirror.
6. **Console/CLI/Export** surface findings and package verifiable evidence; Notify emits digests/incidents.

## Extension Points (Where You Customize)

- **Scanner analyzers** (restart-time plug-ins) for ecosystem-specific parsing and facts extraction.
- **Concelier connectors** for new advisory sources (preserving aggregation-only guardrails).
- **Policy packs** for organization-specific gating and waivers/justifications.
- **Export profiles** for output formats and offline bundle shapes.

## Offline & Sovereign Notes

- Offline Kit carries vulnerability feeds, container images, signatures, and verification material so the workflow stays identical when air-gapped.
- Authority + token verification remain local; quota enforcement is verifiable offline.
- Attestor can cache transparency proofs for offline verification.

## References

- `docs/07_HIGH_LEVEL_ARCHITECTURE.md`
- `docs/24_OFFLINE_KIT.md`
- `docs/09_API_CLI_REFERENCE.md`
- `docs/modules/platform/architecture-overview.md`