feat(bell): add immutable event store [T-015]

deploy/postgres/012_bell_events.sql

@@ -0,0 +1,115 @@
+-- Bell v3 immutable event facts and append-only outcomes.
+-- bell_app remains the migration/object owner; bell_runtime is a NOLOGIN
+-- least-privilege group for the Bell process.
+
+DO $role$
+DECLARE
+    role_record pg_roles%ROWTYPE;
+BEGIN
+    SELECT * INTO role_record FROM pg_roles WHERE rolname = 'bell_runtime';
+    IF NOT FOUND THEN
+        CREATE ROLE bell_runtime NOLOGIN NOSUPERUSER NOCREATEDB NOCREATEROLE NOREPLICATION;
+    ELSIF role_record.rolcanlogin OR role_record.rolsuper OR role_record.rolcreatedb
+       OR role_record.rolcreaterole OR role_record.rolreplication THEN
+        RAISE EXCEPTION 'existing bell_runtime role has unsafe attributes';
+    END IF;
+    IF pg_has_role('bell_runtime', 'bell_app', 'MEMBER')
+       OR pg_has_role('bell_runtime', 'sense_app', 'MEMBER') THEN
+        RAISE EXCEPTION 'bell_runtime must not inherit migration or Sense roles';
+    END IF;
+END
+$role$;
+
+CREATE OR REPLACE FUNCTION bell.reject_immutable_change()
+RETURNS trigger
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = pg_catalog, bell
+AS $function$
+BEGIN
+    RAISE EXCEPTION 'Bell immutable facts cannot be updated or deleted';
+END
+$function$;
+ALTER FUNCTION bell.reject_immutable_change() OWNER TO bell_app;
+
+CREATE TABLE IF NOT EXISTS bell.events (
+    id text PRIMARY KEY,
+    tenant_id bigint NOT NULL,
+    site_id bigint NOT NULL,
+    device_id bigint NOT NULL,
+    source_event_id text NOT NULL,
+    kind text NOT NULL,
+    severity text NOT NULL,
+    occurred_at timestamptz NOT NULL,
+    detected_at timestamptz NOT NULL,
+    payload_hash bytea NOT NULL,
+    payload jsonb NOT NULL,
+    created_at timestamptz NOT NULL DEFAULT clock_timestamp(),
+    CONSTRAINT bell_event_id_format CHECK (id ~ '^evt_[0-9A-HJKMNP-TV-Z]{26}$'),
+    CONSTRAINT bell_event_ids_positive CHECK (tenant_id >= 1 AND site_id >= 1 AND device_id >= 1),
+    CONSTRAINT bell_event_source_id CHECK (source_event_id ~ '^[A-Za-z0-9_-]{1,128}$'),
+    CONSTRAINT bell_event_kind CHECK (kind ~ '^[a-z][a-z0-9_]{2,63}$'),
+    CONSTRAINT bell_event_severity CHECK (severity IN ('low', 'medium', 'high', 'critical')),
+    CONSTRAINT bell_event_time_order CHECK (detected_at >= occurred_at),
+    CONSTRAINT bell_event_hash_length CHECK (octet_length(payload_hash) = 32),
+    CONSTRAINT bell_event_payload_object CHECK (jsonb_typeof(payload) = 'object'),
+    CONSTRAINT bell_event_payload_identity CHECK (
+        payload ->> 'id' = id
+        AND (payload ->> 'tenant_id')::bigint = tenant_id
+        AND (payload ->> 'site_id')::bigint = site_id
+        AND (payload ->> 'device_id')::bigint = device_id
+        AND payload ->> 'source_event_id' = source_event_id
+        AND payload ->> 'kind' = kind
+        AND payload ->> 'severity' = severity
+    )
+);
+ALTER TABLE bell.events OWNER TO bell_app;
+
+DROP TRIGGER IF EXISTS bell_events_immutable ON bell.events;
+CREATE TRIGGER bell_events_immutable
+BEFORE UPDATE OR DELETE ON bell.events
+FOR EACH ROW EXECUTE FUNCTION bell.reject_immutable_change();
+
+CREATE INDEX IF NOT EXISTS bell_events_scope_time_idx
+    ON bell.events(tenant_id, site_id, occurred_at DESC, id DESC);
+CREATE INDEX IF NOT EXISTS bell_events_device_time_idx
+    ON bell.events(tenant_id, site_id, device_id, occurred_at DESC, id DESC);
+CREATE INDEX IF NOT EXISTS bell_events_kind_time_idx
+    ON bell.events(tenant_id, site_id, kind, occurred_at DESC, id DESC);
+CREATE INDEX IF NOT EXISTS bell_events_source_lookup_idx
+    ON bell.events(tenant_id, site_id, device_id, source_event_id);
+
+CREATE TABLE IF NOT EXISTS bell.event_outcomes (
+    id text PRIMARY KEY,
+    event_id text NOT NULL REFERENCES bell.events(id),
+    outcome text NOT NULL,
+    outcome_source text NOT NULL,
+    reason text,
+    actor_type text NOT NULL,
+    actor_id text NOT NULL,
+    occurred_at timestamptz NOT NULL,
+    record_hash bytea NOT NULL,
+    received_at timestamptz NOT NULL DEFAULT clock_timestamp(),
+    CONSTRAINT bell_event_outcome_id_format CHECK (id ~ '^out_[0-9A-HJKMNP-TV-Z]{26}$'),
+    CONSTRAINT bell_event_outcome_value CHECK (
+        outcome IN ('unknown', 'true_positive', 'false_positive', 'subject_recovered', 'duplicate', 'test')
+    ),
+    CONSTRAINT bell_event_outcome_source CHECK (outcome_source IN ('auto', 'manual')),
+    CONSTRAINT bell_event_outcome_actor CHECK (
+        actor_type IN ('user', 'service', 'system') AND btrim(actor_id) <> ''
+    ),
+    CONSTRAINT bell_event_outcome_reason CHECK (reason IS NULL OR char_length(reason) <= 500),
+    CONSTRAINT bell_event_outcome_hash_length CHECK (octet_length(record_hash) = 32)
+);
+ALTER TABLE bell.event_outcomes OWNER TO bell_app;
+
+DROP TRIGGER IF EXISTS bell_event_outcomes_immutable ON bell.event_outcomes;
+CREATE TRIGGER bell_event_outcomes_immutable
+BEFORE UPDATE OR DELETE ON bell.event_outcomes
+FOR EACH ROW EXECUTE FUNCTION bell.reject_immutable_change();
+
+CREATE INDEX IF NOT EXISTS bell_event_outcomes_event_time_idx
+    ON bell.event_outcomes(event_id, occurred_at, id);
+
+INSERT INTO bell.schema_migrations(version) VALUES (3)
+ON CONFLICT (version) DO NOTHING;

deploy/postgres/013_privileges_bell_events.sql

@@ -0,0 +1,15 @@
+-- Runtime Bell can append/read event facts but cannot rewrite, delete or
+-- truncate them. Object ownership stays with the offline migration role.
+
+REVOKE ALL ON FUNCTION bell.reject_immutable_change() FROM PUBLIC;
+REVOKE ALL ON TABLE bell.events, bell.event_outcomes FROM PUBLIC;
+REVOKE ALL ON TABLE bell.events, bell.event_outcomes FROM bell_runtime;
+
+GRANT USAGE ON SCHEMA bell TO bell_runtime;
+GRANT SELECT ON TABLE bell.schema_migrations TO bell_runtime;
+GRANT SELECT, INSERT ON TABLE bell.events, bell.event_outcomes TO bell_runtime;
+
+ALTER DEFAULT PRIVILEGES FOR ROLE bell_app IN SCHEMA bell
+    REVOKE ALL ON TABLES FROM PUBLIC;
+ALTER DEFAULT PRIVILEGES FOR ROLE bell_app IN SCHEMA bell
+    REVOKE ALL ON FUNCTIONS FROM PUBLIC;

deploy/postgres/README.md

@@ -1,6 +1,6 @@
 # YoVision PostgreSQL 初始化
 
-本目录实现 T-009～T-012 的 PostgreSQL `17.10` schema。SQL 必须按文件名前缀顺序执行：`001`～`004` 创建 NOLOGIN 权限角色、Bell/Sense 初始对象和配额权限；`005`～`007` 增量增加 Area 与审计；`008`～`009` 增加 Control API 状态；`010`～`011` 增加调和 fencing、MediaMTX Path 历史归属、孤儿报告/受控处置结果和对应最小权限。全部 SQL 可重放。应用登录角色及其密码由部署环境或密钥系统创建，并分别加入 `bell_app`、`sense_app`；仓库不保存登录凭据。
+本目录实现 T-009～T-012、T-015 的 PostgreSQL `17.10` schema。SQL 必须按文件名前缀顺序执行：`001`～`004` 创建 NOLOGIN 权限角色、Bell/Sense 初始对象和配额权限；`005`～`007` 增量增加 Area 与审计；`008`～`009` 增加 Control API 状态；`010`～`011` 增加调和 fencing、MediaMTX Path 历史归属、孤儿报告/受控处置结果；`012`～`013` 增加 Bell 不可变事件、append-only outcome 和独立 `bell_runtime` 最小权限。全部 SQL 可重放。对象 owner/迁移角色为 `bell_app`/`sense_app`；应用登录角色及密码由部署环境或密钥系统创建，Sense 登录加入 `sense_app`，Bell 运行登录只加入 `bell_runtime`，仓库不保存登录凭据。
 
 生产/共享实例必须由管理员先备份并在 YoVision 专用数据库中执行。Sense 进程不会用高权限自动建库或建角色。示例只使用私有环境变量，不把实际 DSN 写入脚本或日志：
 
@@ -21,6 +21,7 @@ Get-ChildItem deploy/postgres/[0-9][0-9][0-9]_*.sql |
 - `sense_app` 拥有 `sense` schema，只获得 `bell` schema 的 `USAGE` 和两个投影视图的 `SELECT`。
 - `sense_app` 对 Bell 源表、Bell migration 表和 trigger function 没有权限；启动检查发现权限过宽时拒绝运行。
 - `sense.device_operation_outbox` 是本地持久化审计事实，不是 Bell 全局审计真相；relay 的传输、签名、确认和留存尚未实现。
+- `bell.events` 与 `bell.event_outcomes` 由 `bell_app` 拥有；`bell_runtime` 只获得 `SELECT/INSERT`，没有 owner、`UPDATE`、`DELETE` 或 `TRUNCATE` 权限，数据库 trigger 再拒绝 owner 路径的意外事实改写。
 - `sense.control_idempotency_receipts` 不保存原始 Idempotency-Key，只保存 scope/request SHA-256 和脱敏响应快照；`batch_operations`/items 只保存逻辑 ID、状态和稳定错误，不保存连接秘密。
 - 调和与孤儿租约使用 PostgreSQL `clock_timestamp()` 和 fencing token；过期 worker 不能提交完成/失败或扫描报告。`media_path_ownership`、扫描和处置表不保存 endpoint、credential 或 source URI；数据库约束禁止为 `unowned` finding 写删除结果。
 - PUBLIC 对两个业务 schema 的表和函数没有权限。

deploy/postgres/tests/assertions.sql

@@ -71,11 +71,33 @@ BEGIN
        OR NOT has_table_privilege('sense_app', 'sense.device_operation_outbox', 'DELETE') THEN
         RAISE EXCEPTION 'sense_app lacks access to its local audit Outbox';
     END IF;
-    IF (SELECT max(version) FROM bell.schema_migrations) <> 2
+    IF (SELECT max(version) FROM bell.schema_migrations) <> 3
        OR (SELECT max(version) FROM sense.schema_migrations) <> 5 THEN
         RAISE EXCEPTION 'schema migration version drift';
     END IF;
 
+    IF NOT EXISTS (
+        SELECT 1 FROM pg_roles
+        WHERE rolname = 'bell_runtime' AND NOT rolcanlogin AND NOT rolsuper
+          AND NOT rolcreatedb AND NOT rolcreaterole AND NOT rolreplication
+    ) THEN
+        RAISE EXCEPTION 'bell_runtime role is missing or unsafe';
+    END IF;
+    IF NOT has_table_privilege('yovision_t015_bell', 'bell.events', 'SELECT,INSERT')
+       OR NOT has_table_privilege('yovision_t015_bell', 'bell.event_outcomes', 'SELECT,INSERT')
+       OR has_table_privilege('yovision_t015_bell', 'bell.events', 'UPDATE')
+       OR has_table_privilege('yovision_t015_bell', 'bell.events', 'DELETE')
+       OR has_table_privilege('yovision_t015_bell', 'bell.events', 'TRUNCATE')
+       OR has_table_privilege('yovision_t015_bell', 'bell.event_outcomes', 'UPDATE')
+       OR has_table_privilege('yovision_t015_bell', 'bell.event_outcomes', 'DELETE')
+       OR has_table_privilege('yovision_t015_bell', 'bell.event_outcomes', 'TRUNCATE') THEN
+        RAISE EXCEPTION 'Bell runtime violates immutable event privileges';
+    END IF;
+    IF has_table_privilege('public', 'bell.events', 'SELECT,INSERT,UPDATE,DELETE,TRUNCATE')
+       OR has_table_privilege('public', 'bell.event_outcomes', 'SELECT,INSERT,UPDATE,DELETE,TRUNCATE') THEN
+        RAISE EXCEPTION 'Bell event facts leaked to PUBLIC';
+    END IF;
+
     INSERT INTO bell.sites(tenant_id, id, name)
     VALUES ('assertion-tenant', 'assertion-site', 'Assertion Site')
     RETURNING max_video_channels, version INTO default_quota, initial_version;