omnigraph/docs/user/server.md
Ragnor Comerford 937fd6382d
mr-668: remove POST /graphs and CLI graphs create (defer runtime graph mgmt)
The POST /graphs runtime-create endpoint shipped in PR 7/10 has three
unresolved high-severity bugs:

  - flock-on-renamed-inode race: the YAML flock is taken on
    omnigraph.yaml itself, then a temp file is renamed over it.
    Cross-process writers end up locking different inodes — both
    believing they hold exclusive access.
  - duplicate-check outside the file lock: precheck runs against
    the in-memory registry only; the locked closure does
    config.graphs.insert(...) unconditionally. Concurrent same-id
    POSTs can persist the loser in YAML while the in-memory registry
    keeps the winner — they disagree after restart.
  - best_effort_cleanup_init_artifacts deletes _schema.pg /
    _schema.ir.json / __schema_state.json on any init failure. An
    accidental re-init against an existing graph's URI destroys its
    schema; subsequent open() fails at read_text(_schema.pg).

The correct fix is a Lance-style cluster catalog (reserve → init →
publish with recovery sidecars), parallel to the engine's existing
__manifest discipline. That work is out of scope for v0.7.0.

For now, disable runtime add/remove from the network and CLI surface.
Operators add graphs by editing omnigraph.yaml and restarting. The
GET /graphs read-only enumeration stays.

Removed:
- POST /graphs handler + router fragment + utoipa registration
- 13 post_graphs_* server tests + 3 composite POST tests +
  multi_mode_app_with_real_config / post_graph helpers
- CLI omnigraph graphs create subcommand + its handler + cli.rs tests
- system_remote.rs combined list+create test trimmed to list-only
- YAML rewrite infra: rewrite_atomic[_with_modify], RewriteAtomicError,
  staging_path, hash_config_file, AppState::config_hash field +
  threading through new_multi and open_multi_graph_state
- fs2 dependency (verified absent from cargo tree)
- sha2/fs2 imports in config.rs (only the rewrite path used them)
- Cedar PolicyAction::GraphCreate variant + "graph_create" match arms
  + action def in Cedar schema + graph_create_action_authorizes_against_server_resource test
- GraphCreateRequest / GraphCreateResponse / GraphSchemaSpec /
  GraphPolicySpec API types (only the POST handler / CLI imported them)

Kept:
- GET /graphs (read-only enumeration) and graph_list Cedar action
- omnigraph graphs list CLI subcommand
- All multi-graph startup, mode inference, cluster routes,
  per-graph + server-level Cedar policies
- server_settings_drive_multi_graph_startup_end_to_end (the test
  that covers operator-authored YAML + restart — the path that
  survives)
- best_effort_cleanup_init_artifacts and the three init failpoints
  (still reachable from CLI `omnigraph init`; preflight fix deferred
  as a follow-up)
- GraphRegistry::insert and its concurrency tests — production
  callers gone, but the method is the natural seam for the future
  cluster-catalog work

Also fixed (transcript issue 4):
- ALWAYS_FLAT_PATHS now includes /graphs so multi-mode OpenAPI
  advertises the management route correctly (was previously rewritten
  to /graphs/{graph_id}/graphs)
- multi_mode_openapi_keeps_healthz_flat → renamed to
  multi_mode_openapi_keeps_management_paths_flat, asserts both
  /healthz and /graphs stay flat
- multi_mode_openapi_prefixes_operation_ids_with_cluster skips
  /graphs in addition to /healthz

Doc fixes:
- docs/user/cli.md: graphs list example was --target http://...,
  but --target is a config-graph-name lookup; corrected to --uri.
  Removed the graphs create example.
- docs/user/server.md: dropped POST /graphs row, "omnigraph.yaml
  ownership", and "POST /graphs body shape" sections. Added a
  paragraph stating runtime add/remove is not exposed in v0.7.0.
- docs/user/policy.md: dropped graph_create action; reworded the
  "Configuration" line to clarify that server-scoped rules (graph_list)
  take neither branch_scope nor target_branch_scope.
- docs/releases/v0.7.0.md: rewrote release narrative — multi-graph
  mode ships; runtime add/remove deferred.
- AGENTS.md: HTTP server bullet and capability matrix row updated to
  reflect read-only GET /graphs and the operator-edit workflow.
- openapi.json regenerated; /graphs has only .get, no .post.

Diff: 17 files, +123 −1525 LOC.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-26 17:49:38 +02:00

139 lines
7.2 KiB
Markdown

# HTTP Server (`omnigraph-server`)
Axum 0.8 + tokio + utoipa-generated OpenAPI. **Two modes** (v0.7.0+): single-graph (legacy) and multi-graph (MR-668). Mode is inferred from CLI args + config shape.
## Modes
### Single-graph mode (legacy)
`omnigraph-server <URI>` or `omnigraph-server --target <name> --config omnigraph.yaml`. Routes are flat — `/snapshot`, `/read`, `/branches`, etc. Behavior unchanged from v0.6.0.
### Multi-graph mode (v0.7.0+)
`omnigraph-server --config omnigraph.yaml` with a non-empty `graphs:` map and **no** single-mode selector (no `server.graph`, no `<URI>`, no `--target`). The server opens every configured graph in parallel at startup (bounded concurrency = 4, fail-fast on the first open error). Routes are nested under `/graphs/{graph_id}/...`. Bare flat paths return 404 in multi mode.
Mode inference (four-rule matrix):
1. CLI positional `<URI>` → single
2. CLI `--target <name>` → single
3. `server.graph` in config → single
4. `--config` + non-empty `graphs:` + no single-mode selector → **multi**
5. otherwise → error with migration hint
## Endpoint inventory
Per-graph endpoints — same body shape across modes; URLs differ:
| Method | Single-mode path | Multi-mode path | Auth | Action | Handler |
|---|---|---|---|---|---|
| GET | `/healthz` | `/healthz` | none | — | `server_health` |
| GET | `/openapi.json` | `/openapi.json` | none | — | `server_openapi` (strips security if auth disabled; in multi mode emits cluster paths with `cluster_` operation-id prefix) |
| GET | `/snapshot?branch=` | `/graphs/{id}/snapshot?branch=` | bearer + `read` | snapshot of branch | `server_snapshot` |
| POST | `/read` | `/graphs/{id}/read` | bearer + `read` | run named query | `server_read` |
| POST | `/export` | `/graphs/{id}/export` | bearer + `export` | NDJSON stream | `server_export` |
| POST | `/change` | `/graphs/{id}/change` | bearer + `change` | mutation | `server_change` |
| GET | `/schema` | `/graphs/{id}/schema` | bearer + `read` | get current `.pg` source | `server_schema_get` |
| POST | `/schema/apply` | `/graphs/{id}/schema/apply` | bearer + `schema_apply` (target=`main`) | migrate | `server_schema_apply` |
| POST | `/ingest` | `/graphs/{id}/ingest` | bearer + `branch_create` (if new) + `change` | bulk load | `server_ingest` (32 MB body limit) |
| GET | `/branches` | `/graphs/{id}/branches` | bearer + `read` | list branches | `server_branch_list` |
| POST | `/branches` | `/graphs/{id}/branches` | bearer + `branch_create` | create | `server_branch_create` |
| DELETE | `/branches/{branch}` | `/graphs/{id}/branches/{branch}` | bearer + `branch_delete` | delete | `server_branch_delete` |
| POST | `/branches/merge` | `/graphs/{id}/branches/merge` | bearer + `branch_merge` | merge `source → target` | `server_branch_merge` |
| GET | `/commits?branch=` | `/graphs/{id}/commits?branch=` | bearer + `read` | list | `server_commit_list` |
| GET | `/commits/{commit_id}` | `/graphs/{id}/commits/{commit_id}` | bearer + `read` | show | `server_commit_show` |
Server-level management endpoints (v0.7.0+):
| Method | Path | Auth | Action | Handler |
|---|---|---|---|---|
| GET | `/graphs` | bearer + `graph_list` on `Server::"root"` | list registered graphs | `server_graphs_list` (405 in single mode) |
## Adding and removing graphs (multi mode)
Runtime add/remove via API is **not** exposed in v0.7.0 — neither
`POST /graphs` nor `DELETE /graphs/{id}` is implemented. Operators add
or remove graphs by stopping the server, editing the `graphs:` map in
`omnigraph.yaml`, then restarting. The server treats `omnigraph.yaml`
as operator-owned configuration and never writes it.
A future release may introduce a managed registry (Lance-backed,
catalog-style: reserve → init → publish with recovery sidecars) and
re-expose runtime mutation on top of it.
## Streaming
Only `/export` streams (`application/x-ndjson`, MPSC channel + `Body::from_stream`). Everything else is buffered JSON.
## Error model
Uniform `ErrorOutput { error, code?, merge_conflicts[], manifest_conflict? }` with `code ∈ unauthorized | forbidden | bad_request | not_found | conflict | too_many_requests | internal`. Merge conflicts attach structured `MergeConflictOutput { table_key, row_id?, kind, message }`.
`manifest_conflict` is set on **publisher CAS rejections** (HTTP 409): the
caller's pre-write view of one table's manifest version was stale.
`ManifestConflictOutput { table_key, expected, actual }` tells the client
which table to refresh and retry. This is the conflict shape produced by
concurrent `/change` or `/ingest` calls landing the same `(table, branch)`
race.
HTTP status codes used: 200, 400, 401, 403, 404, 409, 429, 500.
## Per-actor admission control
Disjoint
`(table, branch)` writes from different actors now run concurrently,
guarded only by the engine's per-(table, branch) write queue. To keep
one heavy actor from exhausting shared capacity (Lance I/O, manifest
churn, network), the server gates mutating handlers through a
`WorkloadController` configured per-process from environment variables:
| Env var | Default | Purpose |
|---|---|---|
| `OMNIGRAPH_PER_ACTOR_INFLIGHT_MAX` | 16 | Concurrent in-flight mutations per actor |
| `OMNIGRAPH_PER_ACTOR_BYTES_MAX` | 4 GiB | In-flight estimated bytes per actor |
When an actor exceeds its in-flight count or byte budget, the server
returns **HTTP 429 Too Many Requests** with `code: too_many_requests`
and a `Retry-After` header (seconds). The actor should back off; other
actors are unaffected.
Cedar policy authorization runs **before** admission accounting so
denied requests don't consume admission slots.
Today admission gates every mutating handler: `/change`, `/ingest`,
`/branches/{create,delete,merge}`, and `/schema/apply`. Read-only
endpoints (`/snapshot`, `/read`, `/export`, `/branches` GET, `/commits`,
`/schema` GET) are not admission-gated.
## Body limits
- Default: 1 MB
- `/ingest`: 32 MB
## Auth model (`bearer + SHA-256`)
- Tokens are SHA-256 hashed on startup; plaintext is never persisted in memory.
- Constant-time comparison via `subtle::ConstantTimeEq`.
- Three sources, in precedence:
1. `OMNIGRAPH_SERVER_BEARER_TOKENS_AWS_SECRET` — AWS Secrets Manager (build with `--features aws`)
2. `OMNIGRAPH_SERVER_BEARER_TOKENS_FILE` or `OMNIGRAPH_SERVER_BEARER_TOKENS_JSON` — JSON `{actor_id: token, …}`
3. `OMNIGRAPH_SERVER_BEARER_TOKEN` — single legacy token, actor `default`
- If no tokens configured, server runs unauthenticated (local dev) and `/openapi.json` strips the security scheme.
See [deployment.md](deployment.md) for token-source operational details.
## Tracing & observability
- `tower_http::TraceLayer::new_for_http()`
- Policy decisions logged at INFO level with actor, action, branch, decision, matched rule
- Startup logs: token source name, graph URI, bind address
- Graceful SIGINT shutdown
## Not implemented (by design or "TBD")
- CORS — not configured; add `tower_http::cors` if needed.
- Rate limiting — per-actor admission control gates `/change`, `/ingest`,
`/branches/{create,delete,merge}`, `/schema/apply` (see "Per-actor
admission control" above). No global rate limiter is configured;
add `tower_http::limit` if a graph-wide cap is needed.
- Pagination — none (commits/branches return everything; export streams).
- Multi-tenant routing — one graph per process.