tapir/docs/data-model.md

Tapir — Data Model

Current assumptions for the persistence model. Scoped to Stage 0 (single user) and Stage 1 (Future B, 1–5 trusted users). Future C concerns (sharding, cross-tenant dedup) are explicitly excluded and noted at the end.

Persistence is Postgres (ADR-002), reusing the homelab's instance with a per-tenant role when Stage 1 arrives. Secrets (OAuth tokens, BYO keys) are not stored in these tables — only opaque references to them; the secret material lives in ESO/1Password (ADR-002, ADR-006).

Design decisions baked into this model

• Per-user isolation, not a shared global video table. The earlier draft proposed a global videos/transcripts table deduped across tenants. Rejected for Future B: it reintroduces exactly the cross-domain coupling the homelab architecture review is removing, and at 1–5 users the cost of occasionally re-summarizing the same video is trivial compared to the isolation it would cost. Each user's data is self-contained. (Revisit only if Future C makes GPU/transcription cost dominate — a new ADR, not a default.)
• Secrets by reference only. Tables hold a secret_ref (opaque string/UUID resolved via the SecretStore port), never tokens or keys.
• The brain sink is just a delivery target. No brain-specific tables. Whether a summary was also delivered to brain is recorded as sink status on the summary.

Entities

erDiagram
    USER ||--o{ VIDEO_CONNECTION : has
    USER ||--o{ AI_CREDENTIAL : has
    VIDEO_CONNECTION ||--o{ SUBSCRIPTION : exposes
    SUBSCRIPTION ||--o{ VIDEO : "produces (per user)"
    VIDEO ||--o| TRANSCRIPT : "has at most one"
    VIDEO ||--o| SUMMARY : "has at most one"
    SUMMARY ||--o{ SINK_DELIVERY : "delivered via"

    USER {
        uuid id PK
        text display_name
        timestamptz created_at
    }
    VIDEO_CONNECTION {
        uuid id PK
        uuid user_id FK
        text provider "youtube | vimeo"
        text provider_account
        text token_secret_ref "-> SecretStore, never the token"
        text status "active | revoked | error"
        timestamptz connected_at
    }
    AI_CREDENTIAL {
        uuid id PK
        uuid user_id FK
        text provider "anthropic | openai | gemini"
        text key_secret_ref "-> SecretStore, never the key"
        text status
        timestamptz created_at
    }
    SUBSCRIPTION {
        uuid id PK
        uuid user_id FK
        uuid connection_id FK
        text channel_id
        text channel_title
        timestamptz websub_expires "nullable; youtube push lease"
        bool active
    }
    VIDEO {
        uuid id PK
        uuid user_id FK
        uuid subscription_id FK
        text provider
        text provider_video_id
        text title
        int duration_s
        timestamptz published_at
        text url
        timestamptz seen_at
    }
    TRANSCRIPT {
        uuid video_id PK_FK
        uuid user_id FK
        text source "captions | none"
        text language
        text content "null when source = none"
        timestamptz resolved_at
    }
    SUMMARY {
        uuid id PK
        uuid user_id FK
        uuid video_id FK
        text summary
        jsonb highlights
        jsonb takeaways
        text ai_provider "local | anthropic | openai | gemini"
        text ai_model
        bool fallback_used
        timestamptz created_at
    }
    SINK_DELIVERY {
        uuid id PK
        uuid summary_id FK
        text sink "store | brain"
        text status "pending | delivered | error"
        text detail "nullable; error message etc"
        timestamptz updated_at
    }

Notes per entity

• USER — at Stage 0 there is exactly one row. At Stage 1, identity comes via Dex; this table holds the Tapir-side profile keyed to the Dex subject.
• VIDEO_CONNECTION — a connected YouTube/Vimeo account. token_secret_ref resolves to the OAuth refresh token via SecretStore. Revocation flips status, doesn't delete history.
• AI_CREDENTIAL — optional, per provider, per user (ADR-004's Fallback). Absent for users who only use the local stack. One row per provider max.
• SUBSCRIPTION — a watched channel. websub_expires tracks the YouTube push lease so the watcher knows when to re-subscribe; null for poll-based (Vimeo).
• VIDEO — one row per (user, video) — note user_id, reflecting the per-user-isolation decision. The same video seen by two users is two rows. seen_at is when Tapir detected it.
• TRANSCRIPT — at most one per video. source = none records "checked, no usable transcript" so the watcher doesn't reprocess (ADR-007). content null in that case.
• SUMMARY — at most one per video. fallback_used + ai_provider/ai_model make the "is local good enough?" question queryable (the Stage 0 quality signal). highlights/ takeaways as jsonb to stay schema-flexible while the output format settles.
• SINK_DELIVERY — one row per (summary, sink) attempt. This is where "also sent to brain" lives — no brain tables, just a delivery row with sink = brain. Sinks fail independently; a failed brain delivery doesn't fail the store delivery.

Isolation invariant (Stage 1+) — LIVE

Every user-owned table carries user_id, and isolation is enforced at the DB layer, not only in application code. ADR-011 shipped this surface single-user (one allowlisted subject, enforcement dormant); ADR-012 opened Stage 1 and turned enforcement on in the same slice.

Enforcement is Postgres Row-Level Security (migration 003_rls.up.sql):

• RLS is ENABLEd and FORCEd on every user-owned table — users, videos, transcripts, summaries, summary_actions, video_connections. FORCE is load-bearing: the app connects as the table owner (tapir role), and owners bypass RLS unless forced.
• Each policy keys off the per-request GUC tapir.current_user_id, set transaction-locally by the store's withUser helper via set_config('tapir.current_user_id', $1, true) — it auto-resets on commit/rollback, so it never leaks across a pooled connection.
• current_setting('tapir.current_user_id', true) uses missing_ok = true: an unset GUC yields NULL, the predicate matches no rows, and access denies by default.
• sink_deliveries has no user_id; its policy derives ownership from the parent summary via EXISTS (SELECT 1 FROM summaries …).
• user_identities (the Dex-subject → user_id map) is deliberately not RLS-enabled — it is auth plumbing read before a user_id is known; putting RLS there would deadlock. It holds no user data.

The Stage-2 isolation bar is pulled forward, not deferred: internal/adapters/store/rls_test.go runs two users against a non-superuser, non-BYPASSRLS role and asserts user A reads/writes zero of user B's rows across every table. It ships green with the multi-user features (ADR-012); no multi-user feature merges ahead of it passing.

Job / processing state

Execution state (queued / running / retrying) for the watch→resolve→summarize→deliver pipeline is owned by the worker runtime, not modelled as first-class domain tables here. SINK_DELIVERY.status and TRANSCRIPT.source capture the durable, queryable outcomes; a thin jobs table may be added when a "what's processing" view is needed (mirrors the worker queue, doesn't replace it). Deferred until there's a reason.

Explicitly out of scope (Future C)

• Global cross-tenant video/transcript dedup (rejected above).
• Sharding / per-tenant physical databases.
• Soft-delete + full audit trail on connections/credentials (a Stage 2 hardening item; add via ADR when Stage 2 work starts).