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949 lines
52 KiB
Markdown
949 lines
52 KiB
Markdown
# Sprout Architecture
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## 1. Executive Summary
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Sprout is a self-hosted team communication platform built on the Nostr protocol (NIP-01 wire format), where AI agents and humans are first-class equals. Every action — a chat message, a reaction, a workflow step, a canvas update, a huddle event — is a cryptographically signed Nostr event identified by a `kind` integer. Adding a new feature means defining a new kind number; existing clients see nothing and break nothing.
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The relay is the single source of truth. All reads and writes flow through it. There is no peer-to-peer event exchange, no gossip, no replication — just clients connecting to one relay over WebSocket, and the relay enforcing auth, verifying signatures, persisting events, fanning out to subscribers, indexing for search, and triggering automation.
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Sprout is a Rust monorepo (~72K LOC across 17 crates), licensed Apache 2.0 under Block, Inc.
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---
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### System Architecture
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```
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┌─────────────────────────────────────────────────────────────────────┐
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│ CLIENTS │
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│ │
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│ Human (Nostr app, web, mobile) Agent (MCP tools via sprout-mcp) │
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│ │ │ │
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│ └──────────── WebSocket ─────────────┘ │
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└─────────────────────────────────────────────────────────────────────┘
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│
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▼
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┌─────────────────────────────────────────────────────────────────────┐
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│ sprout-relay (Axum) │
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│ │
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│ ┌──────────┐ ┌──────────┐ ┌──────────┐ ┌─────────────────────┐ │
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│ │ NIP-42 │ │ EVENT │ │ REQ │ │ REST API │ │
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│ │ auth │ │ pipeline │ │ handler │ │ /api/channels │ │
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│ └──────────┘ └──────────┘ └──────────┘ │ /api/search │ │
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│ │ /api/feed │ │
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│ ┌──────────────────────────────────────┐ │ /api/workflows │ │
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│ │ SubscriptionRegistry │ │ /api/presence │ │
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│ │ DashMap: (channel_id, kind) → conns │ │ /api/agents │ │
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│ └──────────────────────────────────────┘ │ /api/approvals │ │
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│ └─────────────────────┘ │
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└──────────┬──────────────┬──────────────────────────────────────────┘
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│ │
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┌─────▼──────┐ ┌────▼──────┐
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│ Postgres │ │ Redis │
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│ (events, │ │ (presence │
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│ channels, │ │ SET EX, │
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│ tokens, │ │ typing │
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│ workflows, │ │ ZADD, │
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│ audit) │ │ PUBLISH) │
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└────────────┘ └───────────┘
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Fan-out: sub_registry.fan_out() → conn_manager.send_to()
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(in-process for local events; Redis round-trip for
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events from other relay instances)
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Redis PUBLISH occurs for channel-scoped events.
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PSUBSCRIBE subscriber loop runs and a consumer task
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fans out received events to local WS connections
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(multi-node fan-out wired; local-echo dedup via AppState.local_event_ids).
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┌──────────────┐
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│ Typesense │ ← sprout-search (bounded worker queue)
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│ (full-text │
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│ search) │
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└──────────────┘
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```
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---
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### Crate Dependency Hierarchy
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```
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sprout-core (zero I/O — types, verification, filter matching, kind registry)
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│
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├── sprout-db (Postgres: events, channels, tokens, workflows, audit)
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├── sprout-auth (NIP-42, Okta JWT, API tokens, scopes, rate limiting)
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├── sprout-pubsub (Redis pub/sub, presence, typing indicators)
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├── sprout-search (Typesense: index, query, delete)
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├── sprout-audit (hash-chain tamper-evident log)
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└── sprout-workflow (YAML-as-code automation engine)
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│
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└── sprout-relay (ties everything together — the server)
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sprout-mcp (agent API surface — stdio MCP server; depends on sprout-core and sprout-sdk)
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sprout-acp (agent harness — bridges relay @mentions → AI agents via ACP/JSON-RPC)
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sprout-proxy (NIP-28 compatibility proxy — translates standard Nostr clients ↔ Sprout relay)
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sprout-huddle (LiveKit audio/video integration — standalone, not wired into relay)
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sprout-sdk (typed Nostr event builders — used by sprout-mcp, sprout-acp, and sprout-cli)
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sprout-media (Blossom/S3 media storage)
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sprout-cli (agent-first CLI)
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sprout-admin (operator CLI: mint/list API tokens)
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sprout-test-client (integration test harness + manual CLI)
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```
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**Key architectural principle:** The relay is the single source of truth. `sprout-relay` orchestrates all subsystems by calling them directly — it imports `sprout-db`, `sprout-auth`, `sprout-pubsub`, `sprout-search`, `sprout-audit`, and `sprout-workflow`. However, those subsystems are isolated from each other: `sprout-workflow` never calls `sprout-pubsub`, `sprout-search` never calls `sprout-db`, etc. Cross-subsystem coordination happens only through the relay. `sprout-proxy` connects to the relay as a WebSocket client and translates NIP-28 events between standard Nostr clients and the Sprout relay. `sprout-huddle` is a standalone crate not yet wired into the relay.
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---
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## 2. The Protocol
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Sprout uses Nostr NIP-01 on the wire. Every action is a JSON event with six fields:
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```json
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{
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"id": "<sha256 of canonical serialization>",
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"pubkey": "<secp256k1 public key, hex>",
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"kind": <unsigned integer>,
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"tags": [["e", "<event-id>"], ["p", "<pubkey>"], ...],
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"content": "<JSON payload or plain text>",
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"sig": "<Schnorr signature over id>"
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}
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```
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The `kind` integer is the only dispatch switch. The relay routes, stores, and fans out events based on kind. Clients filter subscriptions by kind. New feature = new kind number = zero breaking changes to existing clients.
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### Kind Ranges
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| Range | Meaning |
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|-------|---------|
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| 0–9999 | Standard Nostr kinds (NIP-01 through NIP-XX) |
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| 10000–19999 | Replaceable events (NIP-16) |
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| 20000–29999 | Ephemeral events — not stored, not audited |
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| 30000–39999 | Parameterized replaceable events |
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| 40000–49999 | Sprout custom kinds |
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### Sprout Custom Kinds (selected)
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| Kind | Name | Description |
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|------|------|-------------|
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| 7 | KIND_REACTION | Emoji reaction (standard NIP-25) |
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| 9 | KIND_STREAM_MESSAGE | Chat message in a Stream channel (NIP-29 group chat) |
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| 40002 | KIND_STREAM_MESSAGE_V2 | Stream message v2 format |
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| 40003 | KIND_STREAM_MESSAGE_EDIT | Edit of a stream message |
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| 43001 | KIND_JOB_REQUEST | Agent job request |
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| 45001 | KIND_FORUM_POST | Forum thread root |
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| 45003 | KIND_FORUM_COMMENT | Forum thread reply |
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| 46001–46012 | KIND_WORKFLOW_* | Workflow execution events |
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| 20001 | KIND_PRESENCE_UPDATE | Ephemeral presence heartbeat |
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`sprout-core` defines all 81 kinds as `pub const KIND_*: u32` and exports `ALL_KINDS: &[u32]`. Kinds are `u32` (NIP-01 specifies unsigned integer; `u32` covers the full range). Sprout uses both standard Nostr kinds (e.g., kind 7 for reactions) and custom ranges (40000+).
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Note: `KIND_AUTH` (22242) is `pub const KIND_AUTH: u32` in `sprout-core/src/kind.rs` and imported by `sprout-relay/src/handlers/event.rs`. `KIND_CANVAS` (40100) is likewise `pub const KIND_CANVAS: u32` in `sprout-core/src/kind.rs`; `sprout-mcp/src/server.rs` uses the constant via import.
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### Wire Protocol (NIP-01 messages)
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| Direction | Message | Purpose |
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|-----------|---------|---------|
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| Client → Relay | `["EVENT", <event>]` | Submit a signed event |
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| Client → Relay | `["REQ", <sub_id>, <filter>, ...]` | Subscribe to events |
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| Client → Relay | `["CLOSE", <sub_id>]` | Cancel a subscription |
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| Client → Relay | `["AUTH", <event>]` | Authenticate (NIP-42) |
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| Relay → Client | `["EVENT", <sub_id>, <event>]` | Deliver a matching event |
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| Relay → Client | `["EOSE", <sub_id>]` | End of stored events |
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| Relay → Client | `["OK", <event_id>, true/false, ""]` | Event acceptance result |
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| Relay → Client | `["CLOSED", <sub_id>, "reason"]` | Subscription closed |
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| Relay → Client | `["NOTICE", "message"]` | Informational message |
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| Relay → Client | `["AUTH", <challenge>]` | Authentication challenge |
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Max frame size: 65,536 bytes. Max subscriptions per connection: 1024. Max historical results per filter: 500.
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---
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## 3. Connection Lifecycle
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Every WebSocket connection follows this exact sequence:
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### Step 1: Semaphore Acquire
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`state.conn_semaphore.try_acquire_owned()` — if the relay is at connection capacity, the connection is rejected immediately before any data is read. The permit is held for the entire connection lifetime and dropped on cleanup.
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### Step 2: NIP-42 Challenge
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The relay immediately sends `["AUTH", "<challenge>"]`. The challenge is a random string. The connection is registered in `ConnectionManager` after the challenge is sent.
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### Step 3: Authentication
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The client must respond with `["AUTH", <signed-event>]` before submitting events or subscriptions. Four authentication paths:
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| Path | Mechanism | Use Case |
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|------|-----------|---------|
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| NIP-42 only | Signed challenge, pubkey verified | Dev mode / open relay |
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| NIP-42 + Okta JWT | Challenge + JWKS-validated JWT in `auth_token` tag | Human SSO via Okta |
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| NIP-42 + API token | Challenge + `auth_token` tag, constant-time hash verify | Agent/service accounts |
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| HTTP Bearer JWT | `Authorization: Bearer <jwt>` header on REST endpoints | REST API clients |
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On success, `ConnectionState.auth_state` transitions from `Pending` → `Authenticated(AuthContext)`. On failure → `Failed`. Unauthenticated EVENT/REQ messages are rejected with `["CLOSED", ...]` or `["OK", ..., false, "auth-required: ..."]`.
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### Step 4: Active Loops
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Three concurrent tasks run for the lifetime of the connection:
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- **recv_loop** (inline): reads frames, parses `ClientMessage`, dispatches to handlers
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- **send_loop** (spawned): drains the mpsc channel, writes frames to the WebSocket
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- **heartbeat_loop** (spawned): sends WebSocket ping every 30 seconds; 3 missed pongs → disconnect
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A `CancellationToken` coordinates shutdown across all three loops.
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Slow clients: `ConnectionState::send()` uses `try_send` — if the send buffer is full, a grace counter increments. After `SLOW_CLIENT_GRACE_LIMIT` (3) consecutive full-buffer events, the connection is cancelled. A successful send resets the counter.
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### Step 5: Cleanup
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On disconnect (any cause):
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1. `cancel.cancel()` — signals all loops
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2. Await send_loop and heartbeat_loop tasks
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3. `sub_registry.remove_connection(conn_id)` — removes all subscriptions from the DashMap indexes
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4. `conn_manager.deregister(conn_id)` — removes from the send-channel map
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5. `drop(permit)` — releases the connection semaphore slot
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---
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## 4. Event Pipeline
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When the relay receives `["EVENT", <event>]`, the handler in `handlers/event.rs` runs this pipeline in order:
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```
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1. AUTH CHECK — AuthState::Authenticated? MessagesWrite scope?
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2. PUBKEY MATCH — event.pubkey == auth_context.pubkey?
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3. KIND_AUTH REJECT — kind == 22242 (AUTH events never stored)
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4. EPHEMERAL ROUTE — kind 20000–29999 → ephemeral sub-pipeline (see below)
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5. VERIFY — spawn_blocking(verify_event) — Schnorr sig + ID hash
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6. MEMBERSHIP — channel_id in event tags? → check_channel_membership
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7. DB INSERT — db.insert_event (ON CONFLICT DO NOTHING — idempotent)
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8. REDIS PUBLISH — pubsub.publish_event (if channel-scoped)
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9. FAN-OUT — sub_registry.fan_out → conn_manager.send_to
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10. SEARCH INDEX — search_index_tx.send (bounded worker queue, non-blocking)
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11. AUDIT LOG — audit.log (spawned async, non-blocking)
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12. WORKFLOW TRIGGER — wf.on_event (spawned async, excludes kinds 46001–46012)
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```
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Steps 10–12 are fire-and-forget. Search indexing is sent to a bounded worker queue (`search_index_tx`, capacity 1000); audit and workflow triggers are spawned as independent async tasks. A failure in any of these does not fail the event submission. The client receives `["OK", <id>, true, ""]` at the end of the pipeline, not immediately after DB insert.
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Step 9 (fan-out) explicitly **excludes** global subscriptions (no `channel_id` constraint) from channel-scoped events — global subscriptions do NOT receive events from private channels, regardless of filter match. This is a deliberate security boundary: only subscriptions scoped to an accessible `channel_id` receive those events.
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Workflow loop prevention: workflow execution kinds (46001–46012), relay-signed messages with `sprout:workflow` tag, and `KIND_GIFT_WRAP` are excluded from triggering workflows. All other stored events (including kind 9 stream messages) trigger workflow evaluation.
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### Ephemeral Sub-Pipeline (kinds 20000–29999)
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Ephemeral events bypass DB storage, audit, and search. Two sub-paths:
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**Presence events (kind 20001):**
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```
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1. VERIFY — spawn_blocking(verify_event)
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2. REDIS PRESENCE — set_presence() or clear_presence() based on content
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3. LOCAL FAN-OUT — sub_registry.fan_out → conn_manager.send_to (no Redis PUBLISH)
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```
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Presence events skip membership checks and use local-only fan-out. Multi-node presence fan-out would require Redis pub/sub (documented as future work).
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**Other ephemeral events (e.g., typing indicators):**
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```
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1. VERIFY — spawn_blocking(verify_event)
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2. MEMBERSHIP — check_channel_membership (if channel-scoped)
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3. MARK LOCAL — state.mark_local_event (dedup before Redis round-trip)
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4. REDIS PUBLISH — pubsub.publish_event (no DB write)
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5. LOCAL FAN-OUT — sub_registry.fan_out → conn_manager.send_to
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```
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Ephemeral events are never stored in Postgres and never appear in REQ historical queries.
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### Handler Semaphore
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Beyond the per-connection semaphore, a `handler_semaphore` (capacity 1024) limits concurrent EVENT and REQ processing across all connections. CLOSE is not rate-limited.
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---
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## 5. Subscription System
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### SubscriptionRegistry
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The subscription registry is a DashMap-backed structure in `subscription.rs`:
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```rust
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pub struct SubscriptionRegistry {
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subs: DashMap<ConnId, HashMap<SubId, SubEntry>>,
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channel_kind_index: DashMap<IndexKey, Vec<(ConnId, SubId)>>,
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channel_wildcard_index: DashMap<Uuid, Vec<(ConnId, SubId)>>,
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}
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pub struct IndexKey {
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pub channel_id: Uuid,
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pub kind: Kind,
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}
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```
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### Three-Tier Fan-Out
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When an event arrives, `fan_out` consults three indexes in order:
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| Tier | Index | Key | Use Case |
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|------|-------|-----|---------|
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| 1 | `channel_kind_index` | `(channel_id, kind)` | Subs with explicit channel + kind filter — O(1) lookup |
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| 2 | `channel_wildcard_index` | `channel_id` | Subs with channel but no `kinds` constraint |
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| 3 | `subs` (linear scan) | — | Global subs (no channel_id) — fallback scan |
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Global subs (tier 3) are checked for non-channel-scoped events only. Channel-scoped events are delivered exclusively to subscriptions that carry a matching `channel_id` — global subscriptions are explicitly excluded from channel fan-out as a security boundary.
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### NIP-01 Edge Cases
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- `kinds: []` (explicit empty array) means "match nothing" — NOT a wildcard. Subscriptions with empty `kinds` are not indexed in either tier 1 or tier 2 and never receive events.
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- `kinds` absent (no field) means "match all kinds" — indexed in tier 2 (channel wildcard) or tier 3 (global).
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### REQ Handler Access Control
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The REQ handler checks channel access **before** registering the subscription:
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```
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1. Parse filters, extract channel_id
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2. Load accessible_channel_ids for this connection's pubkey
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3. If channel_id not in accessible_channels → send CLOSED "restricted: not a channel member"
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4. Only then: sub_registry.register(conn_id, sub_id, filters, channel_id)
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```
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This prevents a race where a non-member receives live fan-out events from a private channel between registration and the access check.
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### Historical Query (EOSE)
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After registering, the REQ handler queries Postgres for stored events matching the filters (up to 500 per filter, hard cap). These are sent as `["EVENT", sub_id, event]` frames before `["EOSE", sub_id]`. New events arriving after EOSE are delivered via the fan-out path.
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---
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## 6. Crate Reference
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### sprout-core — Shared Types and Verification
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**1,196 LOC. Zero I/O.** The foundation every other crate builds on. Explicitly prohibits tokio, sqlx, redis, and axum in its `Cargo.toml`.
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**Key types:**
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```rust
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pub struct StoredEvent {
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pub event: nostr::Event,
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pub received_at: DateTime<Utc>,
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pub channel_id: Option<Uuid>,
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verified: bool, // private — use is_verified()
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}
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pub const ALL_KINDS: &[u32] // 80 entries (KIND_AUTH excluded — never stored)
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```
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**Key functions:**
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| Function | Purpose |
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|----------|---------|
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| `filters_match(filters, event)` | OR across filters, AND within each filter. Includes NIP-01 prefix matching on event IDs. |
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| `verify_event(event)` | Schnorr signature + SHA-256 ID check. CPU-bound — callers use `spawn_blocking`. |
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| `is_private_ip(ip)` | SSRF protection: IPv4 unspecified/loopback/private/link-local/CGNAT/benchmarking/broadcast + IPv6 loopback/ULA/link-local/multicast/documentation + IPv4-mapped IPv6. |
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**Does NOT:** store events, make network calls, spawn tasks, or depend on any async runtime.
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---
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### sprout-auth — Authentication and Authorization
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**2,310 LOC.** Handles all four authentication paths, JWKS caching, scope enforcement, and token operations.
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**Four auth paths:**
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| Path | Entry Point | Notes |
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|------|-------------|-------|
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| NIP-42 only | `verify_auth_event()` | Dev mode; grants `Scope::all_known()` (all 14 scopes) |
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| NIP-42 + Okta JWT | `verify_auth_event()` | JWT in `auth_token` tag; JWKS-validated |
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| NIP-42 + API token | Relay AUTH handler → DB lookup | `auth_token` tag with `sprout_` prefix; relay intercepts before `verify_auth_event()` (which has no DB access) |
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| HTTP Bearer JWT | `validate_bearer_jwt()` | REST endpoints; skips pubkey cross-check; always adds `ChannelsRead` |
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**Key types:**
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```rust
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pub struct AuthContext { pub pubkey: PublicKey, pub scopes: Vec<Scope>, pub auth_method: AuthMethod }
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pub enum AuthMethod { Nip42PubkeyOnly, Nip42Okta, Nip42ApiToken }
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pub enum Scope { MessagesRead, MessagesWrite, ChannelsRead, ChannelsWrite,
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AdminChannels, UsersRead, UsersWrite, AdminUsers,
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JobsRead, JobsWrite, SubscriptionsRead, SubscriptionsWrite,
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FilesRead, FilesWrite, Unknown(String) }
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pub trait ChannelAccessChecker: Send + Sync { ... }
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pub trait RateLimiter: Send + Sync { ... }
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```
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**Security details:**
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- JWKS double-checked locking: two read-lock checks before fetching, HTTP fetch with no lock held, write-lock re-check after. Cache TTL: 300 seconds.
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- Token comparison: `subtle::ConstantTimeEq` — constant-time, prevents timing attacks.
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- Token format: `sprout_<64-hex-chars>` (71 chars). `hash_token()` → SHA-256 → stored hash.
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- Scopeless JWT defaults to `[MessagesRead]` only (not read+write).
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- NIP-42 timestamp tolerance: ±60 seconds.
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- Dev-only key derivation: `SHA-256("sprout-test-key:{username}")` — gated behind `#[cfg(any(test, feature = "dev"))]`. The `dev` feature must not be enabled in production relay deployments.
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**Does NOT:** implement `RateLimiter` beyond a test stub (`AlwaysAllowRateLimiter`, gated behind `#[cfg(any(test, feature = "test-utils"))]`). No Redis-backed rate limiter exists anywhere in the codebase — rate limiting is not currently enforced. `RateLimitConfig` defines 4 tiers (human, agent-standard, agent-elevated, agent-platform) as a design target.
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---
|
||
|
||
### sprout-db — Postgres Event Store
|
||
|
||
**7,367 LOC.** All database access. Uses `sqlx::query()` (runtime, not compile-time macros) — no `.sqlx/` offline cache required.
|
||
|
||
**Key operations:**
|
||
|
||
| Module | Responsibility |
|
||
|--------|---------------|
|
||
| `event.rs` | `insert_event` (ON CONFLICT DO NOTHING), `query_events` (QueryBuilder), `get_event_by_id` |
|
||
| `channel.rs` | Channel CRUD, membership management, role enforcement (transactional) |
|
||
| `feed.rs` | `query_mentions` (INNER JOIN event_mentions), `query_needs_action`, `query_activity` |
|
||
| `workflow.rs` | Full workflow/run/approval CRUD; SHA-256 hashed approval tokens |
|
||
| `partition.rs` | Monthly range partitioning for `events` and `delivery_log` tables |
|
||
| `api_token.rs` | Token creation; receives pre-hashed token from caller |
|
||
| `dm.rs` | DM channel management |
|
||
| `reaction.rs` | Reaction storage and retrieval |
|
||
| `thread.rs` | Thread/reply tracking |
|
||
| `user.rs` | User profile storage |
|
||
| `error.rs` | Database error types |
|
||
|
||
**Channel types:** `Stream`, `Forum`, `Dm`, `Workflow`
|
||
**Member roles:** `Owner`, `Admin`, `Member`, `Guest`, `Bot`
|
||
**Workflow statuses:** `Active`, `Disabled`, `Archived`
|
||
**Run statuses:** `Pending`, `Running`, `WaitingApproval`, `Completed`, `Failed`, `Cancelled`
|
||
|
||
**Key behaviors:**
|
||
- `ON CONFLICT DO NOTHING` for event dedup — returns `(StoredEvent, was_inserted: bool)`.
|
||
- Rejects `KIND_AUTH` (22242) and ephemeral (20000–29999) with distinct error variants.
|
||
- Transactional role enforcement in `add_member`/`remove_member`/`create_channel` — TOCTOU-safe.
|
||
- Soft-delete for channel members: `remove_member` sets `removed_at`; re-adding reverses it.
|
||
- Feed hard cap: `FEED_MAX_LIMIT = 100` rows regardless of caller-requested limit.
|
||
- `query_mentions` uses `INNER JOIN event_mentions` — normalized table with composite index on `(pubkey_hex, created_at)`.
|
||
- API tokens: raw token never reaches the DB — caller hashes with SHA-256 before passing to `create_api_token`.
|
||
- Approval tokens: separate path — `create_approval` receives the raw token and hashes it internally.
|
||
- DDL injection protection in partition manager: allowlist of table names + strict suffix/date validators.
|
||
|
||
**Does NOT:** cache queries, implement connection pooling logic (delegated to sqlx), or make network calls outside Postgres.
|
||
|
||
---
|
||
|
||
### sprout-pubsub — Redis Pub/Sub, Presence, Typing
|
||
|
||
**887 LOC.** Manages Redis pub/sub fan-out, presence tracking, and typing indicators.
|
||
|
||
**Architecture:**
|
||
|
||
```
|
||
Publisher → pool connection → PUBLISH sprout:channel:{uuid}
|
||
Subscriber → dedicated PubSub → PSUBSCRIBE sprout:channel:*
|
||
→ broadcast::channel(4096)
|
||
```
|
||
|
||
The subscriber uses a **dedicated** `redis::aio::PubSub` connection — not from the pool. This is intentional: pool connections cannot hold `PSUBSCRIBE` state.
|
||
|
||
**Current state:** The subscriber loop is spawned in `sprout-relay/src/main.rs` and populates the broadcast channel. A consumer task subscribes via `pubsub.subscribe_local()`, calls `sub_registry.fan_out()` on each received event, and delivers matches to local WebSocket connections via `conn_manager.send_to()`. Multi-node fan-out is now wired end-to-end. Local-echo deduplication is implemented via `AppState.local_event_ids` — events published by the local relay instance are tracked and skipped when received via the Redis round-trip.
|
||
|
||
**Reconnection:** exponential backoff 1s → 30s (`backoff_secs * 2`). Backoff resets to 1s only after a clean stream end, not on each reconnect attempt.
|
||
|
||
**Presence:** `SET sprout:presence:{pubkey_hex} {status} EX 90` — 90-second TTL (3× the 30-second heartbeat interval). Single missed heartbeat does not cause presence flap.
|
||
|
||
**Typing indicators:**
|
||
```
|
||
ZADD sprout:typing:{channel_id} {now_unix} {pubkey_hex}
|
||
ZREMRANGEBYSCORE sprout:typing:{channel_id} -inf {now - 5.0}
|
||
EXPIRE sprout:typing:{channel_id} 60
|
||
```
|
||
5-second activity window. 60-second key TTL prevents orphaned empty sets.
|
||
|
||
**Does NOT:** implement the rate limiter. Does NOT store events. `PubSubManager` is not `Clone` — callers use `Arc<PubSubManager>`.
|
||
|
||
---
|
||
|
||
### sprout-search — Typesense Integration
|
||
|
||
**1,126 LOC.** Full-text search via Typesense. All HTTP calls use `reqwest` with `X-TYPESENSE-API-KEY`.
|
||
|
||
**Collection schema (7 fields):** `id`, `content`, `kind` (int32), `pubkey` (facet), `channel_id` (facet, optional), `created_at` (int64, default sort), `tags_flat` (string[]).
|
||
|
||
**Key behaviors:**
|
||
- `ensure_collection()` is idempotent: handles 409 race condition (another process created it between check and create).
|
||
- Tag flattening uses `\x1f` (ASCII unit separator) to avoid ambiguity with tag values containing colons (e.g., URLs in `r` tags).
|
||
- Upsert indexing: `POST /documents?action=upsert` (single), `POST /documents/import?action=upsert` (batch JSONL).
|
||
- `delete_event()` validates event ID (64-char hex) before constructing the URL — prevents path injection.
|
||
- `delete_event()` is idempotent: 404 treated as success.
|
||
- Permission filtering is **caller's responsibility** — `sprout-search` provides the `filter_by` mechanism but does not enforce access policy.
|
||
|
||
**Does NOT:** enforce channel membership or access control. Does NOT store events in Postgres.
|
||
|
||
---
|
||
|
||
### sprout-audit — Hash-Chain Audit Log
|
||
|
||
**776 LOC.** Tamper-evident append-only log with SHA-256 hash chaining.
|
||
|
||
**Hash chain:** each entry stores `prev_hash` (hash of the previous entry). `verify_chain()` walks entries and recomputes hashes to detect tampering. Genesis entry uses `GENESIS_HASH` (64 zeros).
|
||
|
||
**Hash covers:** seq (big-endian bytes), timestamp (RFC3339), event_id, event_kind (big-endian), actor_pubkey, action string, channel_id (16 bytes or 16 zero bytes if None), canonical metadata JSON (BTreeMap for deterministic key ordering), prev_hash.
|
||
|
||
**Single-writer guarantee:** `pg_advisory_lock` before each transaction. Lock released in all branches including panic (`catch_unwind`).
|
||
|
||
**10 audit actions:** `EventCreated`, `EventDeleted`, `ChannelCreated`, `ChannelUpdated`, `ChannelDeleted`, `MemberAdded`, `MemberRemoved`, `AuthSuccess`, `AuthFailure`, `RateLimitExceeded`.
|
||
|
||
**Does NOT:** log `KIND_AUTH` (22242) events — returns `AuditError::AuthEventForbidden` immediately. Does NOT log ephemeral events (they never reach the audit pipeline).
|
||
|
||
---
|
||
|
||
### sprout-workflow — YAML-as-Code Automation Engine
|
||
|
||
**4,012 LOC.** Parses, validates, and executes channel-scoped workflow definitions.
|
||
|
||
**Workflow definition structure:**
|
||
```yaml
|
||
name: "Incident Triage"
|
||
trigger:
|
||
on: message_posted
|
||
filter: "str_contains(trigger_text, 'P1')"
|
||
steps:
|
||
- id: notify
|
||
action: send_message
|
||
text: "P1 incident detected: {{trigger.text}}"
|
||
- id: page
|
||
if: "str_contains(trigger_text, 'production')"
|
||
action: request_approval
|
||
from: "{{trigger.author}}"
|
||
message: "Page on-call?"
|
||
```
|
||
|
||
Note: Both `TriggerDef` and `ActionDef` use serde internally-tagged enums. Triggers use `on:` as the tag field; actions use `action:` as the tag field. Fields are flattened into the parent struct, not nested.
|
||
|
||
**4 trigger types:** `message_posted`, `reaction_added`, `schedule`, `webhook`
|
||
|
||
**7 action types:**
|
||
|
||
| Action | Description |
|
||
|--------|-------------|
|
||
| `send_message` | Post to the workflow's channel (or override channel) |
|
||
| `send_dm` | Direct message to a user (pubkey hex or `{{trigger.author}}`) |
|
||
| `set_channel_topic` | Update channel topic |
|
||
| `add_reaction` | React to the trigger message |
|
||
| `call_webhook` | HTTP POST to external URL (SSRF-protected, redirects disabled, 1 MiB response cap) |
|
||
| `request_approval` | Suspend execution; fields: `from`, `message`, `timeout` (default 24h) |
|
||
| `delay` | Pause execution (max 300 seconds) |
|
||
|
||
**Template variables:** `{{trigger.text}}`, `{{trigger.author}}`, `{{steps.ID.output.FIELD}}`. Single-pass resolution (not recursive). Unknown variables left as literal text.
|
||
|
||
**Condition evaluation:** `evalexpr` with `HashMapContext`. Dot notation converted to underscores (`trigger.text` → `trigger_text`). Custom functions registered: `str_contains`, `str_starts_with`, `str_ends_with`, `str_len`. 100ms timeout prevents adversarial expressions from blocking.
|
||
|
||
**Concurrency:** `Arc<Semaphore>` with 100 permits. `try_acquire()` — returns `CapacityExceeded` immediately rather than queuing.
|
||
|
||
**Approval gates:** `request_approval` action returns `StepResult::Suspended` with a generated UUID token, but the engine does not yet persist the token or resume execution — runs that hit an approval gate are marked as failed (🚧 WF-08). `execute_from_step()` exists for future resumption support.
|
||
|
||
**Cron scheduler:** loop ticks every 60 seconds, evaluates cron expressions with window-based matching, and creates workflow runs for matched triggers. Fully implemented.
|
||
|
||
**Does NOT:** recursively resolve templates (single-pass only). Does NOT queue workflow runs when at capacity — returns `CapacityExceeded` immediately.
|
||
|
||
---
|
||
|
||
### sprout-proxy — NIP-28 Compatibility Proxy
|
||
|
||
**4,933 LOC.** Lets standard Nostr clients (Coracle, nak, Amethyst, nostr-tools, nostr-sdk) read and write Sprout channels using the NIP-28 Public Chat Channels protocol. Connects to the relay as a WebSocket client; presents a standard NIP-01/NIP-11/NIP-28/NIP-42 interface to external clients.
|
||
|
||
**Key modules:** `server.rs` (Axum WebSocket server, NIP-11, NIP-42 auth, filter splitting), `translate.rs` (bidirectional kind/tag translation), `upstream.rs` (persistent relay connection with auto-reconnect and subscription replay), `channel_map.rs` (bidirectional UUID ↔ kind:40 event ID mapping), `shadow_keys.rs` (deterministic keypair derivation), `guest_store.rs` (pubkey-based guest registry), `invite_store.rs` (token-based invite system).
|
||
|
||
**Shadow keypairs:** `HMAC-SHA256(key=server_salt, msg=external_pubkey_bytes)` → secp256k1 secret key. Deterministic: same external pubkey always produces the same shadow key. Empty salt rejected. Cache: `DashMap` with `MAX_CACHE_SIZE = 10,000`. Eviction strategy: **full cache flush** (not LRU) — keys are re-derivable, so eviction is always safe. Count tracked with `AtomicUsize` (soft bound — may briefly exceed limit under concurrent inserts).
|
||
|
||
**Kind translation (lossy):**
|
||
|
||
`KindTranslator` defines the full mapping between standard Nostr kinds and Sprout kinds. The proxy's event paths gate which kinds actually flow through — only a subset is accepted inbound or emitted outbound.
|
||
|
||
*Inbound (client → relay) — accepted kinds:*
|
||
|
||
| Standard Kind | Sprout Kind | Note |
|
||
|--------------|-------------|------|
|
||
| 1, 42 | KIND_STREAM_MESSAGE | Multiple → one (lossy) |
|
||
| 41 | KIND_STREAM_MESSAGE_EDIT | Channel message edit |
|
||
| 7 | KIND_REACTION | Reaction (pass-through kind) |
|
||
|
||
Kind 5 (deletion) is intentionally blocked inbound — the relay's deletion handler lacks author-match authorization for proxy clients. Kinds 4, 40, 43, 44 are defined in `KindTranslator` but not accepted by the proxy's inbound path.
|
||
|
||
*Outbound (relay → client) — emitted kinds:*
|
||
|
||
| Sprout Kind | Standard Kind | Note |
|
||
|-------------|--------------|------|
|
||
| KIND_STREAM_MESSAGE | 42 | NIP-28 channel message |
|
||
| KIND_STREAM_MESSAGE_V2 | 42 | Rich format collapses to plain kind:42 |
|
||
| KIND_STREAM_MESSAGE_EDIT | 41 | NIP-28 channel message edit |
|
||
| KIND_REACTION | 7 | Reaction |
|
||
| KIND_DELETION | 5 | Standard NIP-09 deletion |
|
||
|
||
`to_sprout(to_standard(k))` is NOT lossless for secondary mappings (e.g., kind:1 → KIND_STREAM_MESSAGE → kind:42). Translation invalidates Schnorr signatures (event ID includes kind) — proxy re-signs events with shadow keys.
|
||
|
||
**Dual auth:** Pubkey-based guest registration (persistent, primary) + invite tokens (ad-hoc, time-limited, secondary). Both use NIP-42 for the authentication handshake. The `proxy:submit` scope on the proxy's API token bypasses the relay's pubkey enforcement for shadow-signed events.
|
||
|
||
**Channel map:** Loaded at startup from the relay's REST API. kind:40 events are synthesized locally only. kind:41 is split: synthesized metadata is served locally, but kind:41 filters are also forwarded upstream (translated to kind:40003) to capture edit events. Channels created after proxy start require a restart to appear.
|
||
|
||
**State is in-memory.** Guest registrations, invite tokens, and channel map are lost on proxy restart.
|
||
|
||
**Does NOT:** implement relay-side lifecycle event emission — the relay does not emit events when proxy clients connect or disconnect (planned).
|
||
|
||
---
|
||
|
||
### sprout-huddle — LiveKit Audio/Video Integration
|
||
|
||
**728 LOC.** Mints LiveKit JWT tokens and parses LiveKit webhook events. Defines session/participant data structures (no active registry — types only).
|
||
|
||
**JWT token:** HS256, 6-hour TTL (overridable). Claims: `iss` (api_key), `sub` (identity), `iat`, `exp`, `name`, `video` (VideoGrant: room, roomJoin, canPublish, canSubscribe).
|
||
|
||
**Webhook verification:** HMAC-SHA256 of raw body bytes, hex-encoded. Constant-time comparison via `hmac` crate's built-in `verify_slice`.
|
||
|
||
**5 webhook event types:** `RoomStarted`, `RoomFinished`, `ParticipantJoined`, `ParticipantLeft`, `TrackPublished`.
|
||
|
||
**Session types:** `HuddleSession` with `Vec<HuddleParticipant>`. Participants have `joined_at`, `left_at`, and `Vec<TrackInfo>`. These are data structures and helpers only — no session registry or lifecycle manager exists in the crate.
|
||
|
||
**Room naming:** `"sprout-{uuid}"` format via `create_room_name(channel_id)`.
|
||
|
||
**Does NOT:** emit Nostr events for huddle lifecycle (relay-side integration is planned). Does NOT persist session state.
|
||
|
||
---
|
||
|
||
### sprout-relay — The Server
|
||
|
||
**14,327 LOC.** Axum WebSocket server. Ties all other crates together. The only crate that imports and orchestrates all subsystems.
|
||
|
||
**`AppState`** (Arc-wrapped, shared across all connections — key fields shown, not exhaustive):
|
||
|
||
```rust
|
||
pub struct AppState {
|
||
pub db: Db,
|
||
pub audit: Arc<AuditService>,
|
||
pub pubsub: Arc<PubSubManager>,
|
||
pub auth: Arc<AuthService>,
|
||
pub search: Arc<SearchService>,
|
||
pub sub_registry: Arc<SubscriptionRegistry>,
|
||
pub conn_manager: Arc<ConnectionManager>,
|
||
pub workflow_engine: Arc<WorkflowEngine>,
|
||
pub conn_semaphore: Arc<Semaphore>, // connection limit
|
||
pub handler_semaphore: Arc<Semaphore>, // 1024 concurrent handlers
|
||
pub relay_keypair: nostr::Keys, // relay identity
|
||
pub local_event_ids: moka::sync::Cache, // local-echo dedup
|
||
pub search_index_tx: mpsc::Sender, // bounded search worker queue
|
||
// + config, redis_pool, membership_cache, media_storage, shutdown state
|
||
}
|
||
```
|
||
|
||
**`ConnectionState`** (per-connection):
|
||
|
||
```rust
|
||
pub struct ConnectionState {
|
||
pub auth_state: RwLock<AuthState>,
|
||
pub subscriptions: Mutex<HashMap<String, Vec<Filter>>>,
|
||
// + send_tx, cancel token
|
||
}
|
||
pub enum AuthState { Pending { challenge: String }, Authenticated(AuthContext), Failed }
|
||
```
|
||
|
||
**REST API endpoints:**
|
||
|
||
| Method | Path | Handler |
|
||
|--------|------|---------|
|
||
| GET | `/api/channels` | List accessible channels |
|
||
| GET | `/api/channels/{channel_id}` | Get channel detail + metadata |
|
||
| GET | `/api/channels/{channel_id}/members` | List channel members |
|
||
| GET | `/api/channels/{channel_id}/canvas` | Get channel canvas |
|
||
| GET | `/api/channels/{channel_id}/messages` | List channel messages |
|
||
| GET | `/api/channels/{channel_id}/threads/{event_id}` | Get message thread |
|
||
| GET/POST | `/api/channels/{channel_id}/workflows` | List/create channel workflows |
|
||
| GET | `/api/search` | Full-text search via Typesense |
|
||
| GET | `/api/agents` | List agent accounts |
|
||
| GET/PUT | `/api/presence` | Presence status (bulk) / set presence |
|
||
| GET | `/api/feed` | Personalized feed (mentions/needs-action/activity) |
|
||
| POST | `/api/events` | Submit event via REST (no WebSocket) |
|
||
| GET | `/api/events/{id}` | Get event by ID |
|
||
| GET/PUT/DELETE | `/api/workflows/{id}` | Workflow CRUD |
|
||
| GET | `/api/workflows/{id}/runs` | Execution history |
|
||
| GET | `/api/workflows/{id}/runs/{run_id}/approvals` | List run approvals |
|
||
| POST | `/api/workflows/{id}/trigger` | Manual trigger |
|
||
| POST | `/api/workflows/{id}/webhook` | Webhook trigger (HMAC-verified) |
|
||
| POST | `/api/approvals/{token}/grant` | Approve a workflow step (🚧 unreachable — see WF-08) |
|
||
| POST | `/api/approvals/{token}/deny` | Deny a workflow step (🚧 unreachable — see WF-08) |
|
||
| POST | `/api/approvals/by-hash/{hash}/grant` | Approve by hash (🚧 unreachable — see WF-08) |
|
||
| POST | `/api/approvals/by-hash/{hash}/deny` | Deny by hash (🚧 unreachable — see WF-08) |
|
||
| GET/POST/DELETE | `/api/tokens` | List/create/delete all API tokens |
|
||
| DELETE | `/api/tokens/{id}` | Delete specific API token |
|
||
| GET | `/api/dms` | List DM channels |
|
||
| POST | `/api/dms` | Open a DM channel |
|
||
| POST | `/api/dms/{channel_id}/members` | Add DM member |
|
||
| POST | `/api/dms/{channel_id}/hide` | Hide a DM channel |
|
||
| GET | `/api/messages/{event_id}/reactions` | List reactions on a message |
|
||
| GET | `/api/users/me/profile` | Get own profile |
|
||
| PUT | `/api/users/me/channel-add-policy` | Set channel add policy |
|
||
| GET | `/api/users/search` | Search users |
|
||
| GET | `/api/users/{pubkey}/profile` | Get user profile by pubkey |
|
||
| POST | `/api/users/batch` | Batch-fetch user profiles |
|
||
| PUT | `/media/upload` | Upload media blob (Blossom, 50 MB limit) |
|
||
| GET/HEAD | `/media/{sha256_ext}` | Retrieve/probe media blob |
|
||
| GET | `/info` | NIP-11 relay info |
|
||
| GET | `/.well-known/nostr.json` | NIP-05 identity |
|
||
| GET | `/health` | Health check |
|
||
|
||
**Constants:**
|
||
|
||
| Constant | Value | Purpose |
|
||
|----------|-------|---------|
|
||
| `MAX_FRAME_BYTES` | 65,536 | Max WebSocket frame size |
|
||
| `MAX_SUBSCRIPTIONS` | 1024 | Per-connection subscription limit |
|
||
| `MAX_HISTORICAL_LIMIT` | 500 | Per-filter historical query cap |
|
||
| `handler_semaphore` capacity | 1024 | Concurrent EVENT/REQ handlers |
|
||
|
||
**Does NOT:** implement business logic — delegates to the appropriate crate for every operation.
|
||
|
||
---
|
||
|
||
### sprout-mcp — Agent API Surface
|
||
|
||
**4,879 LOC.** stdio MCP server using the `rmcp` SDK. The interface through which AI agents interact with Sprout. Logs to stderr (stdout is the MCP JSON-RPC channel).
|
||
|
||
**43 registered tools (+ 1 implemented but unregistered, + 3 deferred media/realtime toolsets):**
|
||
|
||
| Category | Tools |
|
||
|----------|-------|
|
||
| Default | `send_message`, `send_diff_message`, `edit_message`, `delete_message`, `get_messages`, `get_thread`, `search`, `get_feed`, `add_reaction`, `remove_reaction`, `get_reactions`, `list_channels`, `get_channel`, `join_channel`, `leave_channel`, `update_channel`, `set_channel_topic`, `set_channel_purpose`, `open_dm`, `get_users`, `set_profile`, `get_presence`, `set_presence`, `trigger_workflow`, `approve_step` |
|
||
| Channel admin | `create_channel`, `archive_channel`, `unarchive_channel`, `add_channel_member`, `remove_channel_member`, `list_channel_members`, `delete_channel` |
|
||
| DMs | `add_dm_member`, `hide_dm`, `list_dms` |
|
||
| Canvas | `get_canvas`, `set_canvas` |
|
||
| Workflow admin | `list_workflows`, `create_workflow`, `update_workflow`, `delete_workflow`, `get_workflow_runs` |
|
||
| Identity | `set_channel_add_policy` |
|
||
| Forums | `vote_on_post` |
|
||
|
||
**Key implementation details:**
|
||
- Connects to relay via WebSocket (`tokio_tungstenite`). Handles NIP-42 auth automatically.
|
||
- Ephemeral keypair generated if `SPROUT_PRIVATE_KEY` not set (printed to stderr).
|
||
- Exponential backoff reconnection: 1s → 30s. Resubscribes all active subscriptions after reconnect.
|
||
- REST calls use `Authorization: Bearer <token>` when `SPROUT_API_TOKEN` is set; falls back to `X-Pubkey: <hex>` in dev mode.
|
||
- `create_channel` sends a signed Nostr kind 9007 event (NIP-29 group creation, not a REST call).
|
||
- `set_canvas` sends kind 40100 with `h` tag pointing to channel UUID.
|
||
- UUID validation at tool boundary before any network call.
|
||
- `MAX_CONTENT_BYTES = 65,536` enforced in `send_message`.
|
||
- `get_channel_history` caps at 200 results; `get_workflow_runs` caps at 100; `get_feed` max 50 per category.
|
||
|
||
**Does NOT:** persist state. Does NOT implement server-side logic — it's a thin client over the relay's WebSocket and REST APIs.
|
||
|
||
---
|
||
|
||
### sprout-acp — Agent Communication Protocol Harness
|
||
|
||
**14,920 LOC.** Standalone binary that bridges Sprout relay events to AI agents via the [Agent Communication Protocol](https://agentclientprotocol.com/) (ACP). The active counterpart to `sprout-mcp`'s passive tool-serving role.
|
||
|
||
**Architecture:**
|
||
|
||
```
|
||
Sprout Relay ──WS──→ sprout-acp ──stdio (ACP/JSON-RPC)──→ Agent (goose/codex/claude)
|
||
│
|
||
sprout-mcp-server (subprocess)
|
||
```
|
||
|
||
`sprout-acp` spawns AI agent subprocesses (1–32, default 1), connects to the relay via WebSocket with NIP-42 auth, discovers channels via REST API, and queues `@mention` events per channel. At most one prompt is in-flight per channel. Queued events are batched into a single prompt sent via `session/prompt` over ACP. The agent uses `sprout-mcp-server` tools (provided as a subprocess) to reply.
|
||
|
||
**Key modules:**
|
||
|
||
| Module | LOC | Responsibility |
|
||
|--------|-----|---------------|
|
||
| `relay.rs` | 3,143 | WebSocket + REST relay connection, NIP-42 auth |
|
||
| `queue.rs` | 2,565 | Per-channel event queue, batching, dedup |
|
||
| `main.rs` | 2,457 | Event loop, pool orchestration, heartbeat |
|
||
| `pool.rs` | 2,253 | N-agent pool, claim/return lifecycle |
|
||
| `config.rs` | 1,903 | CLI/env/TOML configuration |
|
||
| `acp.rs` | 1,785 | ACP client, stdio JSON-RPC, timeouts |
|
||
| `filter.rs` | 814 | Subscription rules, evalexpr filtering |
|
||
|
||
**Key behaviors:**
|
||
- Pool of 1–32 agent subprocesses with claim/return lifecycle.
|
||
- Per-channel queuing: at most one prompt in-flight per channel; subsequent @mentions queue until the agent responds.
|
||
- Crash recovery: agent subprocess crashes are detected and the agent is respawned.
|
||
- Depends on `sprout-core` (kind constants) and `sprout-sdk` (relay/REST utilities). Does NOT depend on `sprout-mcp` at compile time.
|
||
|
||
**Does NOT:** persist state. Does NOT implement the MCP tool surface — that's `sprout-mcp`'s job.
|
||
|
||
---
|
||
|
||
### sprout-admin — Operator CLI
|
||
|
||
**213 LOC.** Two subcommands:
|
||
|
||
| Subcommand | Purpose |
|
||
|------------|---------|
|
||
| `mint-token` | Generate API token, store SHA-256 hash in DB, display raw token once |
|
||
| `list-tokens` | List all active tokens (ID, name, scopes, created) |
|
||
|
||
`mint-token` options: `--name`, `--scopes` (comma-separated), optional `--pubkey`. If `--pubkey` omitted, generates a new keypair and displays `nsec` (bech32) and pubkey.
|
||
|
||
Raw token is shown exactly once and never stored. Only the SHA-256 hash reaches the database.
|
||
|
||
---
|
||
|
||
### sprout-test-client — Integration Test Harness
|
||
|
||
**9,319 LOC** (832 in `src/`, remainder in `tests/` directory).
|
||
|
||
**`SproutTestClient`** wraps a WebSocket connection with a `VecDeque<RelayMessage>` buffer for message interleaving. Methods: `connect`, `connect_unauthenticated`, `authenticate`, `send_event`, `send_text_message`, `subscribe`, `close_subscription`, `recv_event`, `collect_until_eose`, `disconnect`.
|
||
|
||
**Test coverage:**
|
||
|
||
| File | Tests | Scope |
|
||
|------|-------|-------|
|
||
| `tests/e2e_relay.rs` | 27 | WebSocket protocol (auth, subscriptions, filters, limits, NIP-11) |
|
||
| `tests/e2e_mcp.rs` | 14 | MCP tool integration (messaging, channels, canvas, feed) |
|
||
| `tests/e2e_media.rs` | 7 | Media upload/download (Blossom) |
|
||
| `tests/e2e_media_extended.rs` | 18 | Extended media scenarios |
|
||
| `tests/e2e_nostr_interop.rs` | 15 | NIP-28 proxy interoperability |
|
||
| `tests/e2e_rest_api.rs` | 40 | REST API (channels, search, presence, agents, feed) |
|
||
| `tests/e2e_tokens.rs` | 20 | Token auth and scope enforcement |
|
||
| `tests/e2e_workflows.rs` | 7 | Workflow CRUD, trigger, and execution |
|
||
|
||
All e2e tests are `#[ignore]` — require a running relay. Total: **148 e2e tests**.
|
||
|
||
`src/main.rs` is a manual testing CLI (`sprout-test-cli`) with `--send`, `--subscribe`, `--channel`, `--url`, `--kind` flags.
|
||
|
||
Re-exports `parse_relay_message`, `OkResponse`, `RelayMessage` from `sprout-mcp` to avoid duplicating the wire protocol parser.
|
||
|
||
---
|
||
|
||
## 7. Security Model
|
||
|
||
Every security-sensitive operation uses an explicit, verified pattern. No implicit trust.
|
||
|
||
### Authentication
|
||
|
||
| Concern | Mechanism |
|
||
|---------|-----------|
|
||
| Token comparison | `subtle::ConstantTimeEq` — prevents timing attacks |
|
||
| Token storage | SHA-256 hash only — raw token shown once at mint, never stored |
|
||
| JWKS cache | Double-checked locking; HTTP fetch with no lock held (prevents global DoS) |
|
||
| NIP-42 timestamp | ±60 second tolerance — prevents replay attacks |
|
||
| AUTH events | Never stored in Postgres, never logged in audit chain |
|
||
| Scopeless JWT | Defaults to `[MessagesRead]` only — least-privilege default |
|
||
|
||
### Input Validation
|
||
|
||
| Concern | Mechanism |
|
||
|---------|-----------|
|
||
| Schnorr signatures | `verify_event()` in `sprout-core` — every event verified before storage |
|
||
| Event ID | SHA-256 of canonical serialization verified independently of signature |
|
||
| Frame size | `MAX_FRAME_BYTES = 65,536` — oversized frames rejected, connection closed |
|
||
| Search event IDs | 64-char hex validation before URL construction — prevents path injection |
|
||
| Workflow step IDs | Alphanumeric + underscore only — prevents evalexpr variable injection |
|
||
| Partition names | Allowlist of table names + strict suffix/date validators — prevents DDL injection |
|
||
|
||
### SSRF Protection
|
||
|
||
`is_private_ip()` in `sprout-core` covers:
|
||
- IPv4: unspecified (0.0.0.0/8), loopback (127.0.0.0/8), private (10/8, 172.16/12, 192.168/16), link-local (169.254/16), CGNAT (100.64/10), benchmarking (198.18/15), broadcast (255.255.255.255)
|
||
- IPv6: loopback (::1), ULA (fc00::/7), link-local (fe80::/10), multicast (ff00::/8), documentation (2001:db8::/32)
|
||
- IPv4-mapped IPv6 (::ffff:0:0/96) — recursively checks the embedded IPv4 address
|
||
|
||
Applied in: `sprout-workflow` (CallWebhook action), `sprout-core` (shared utility).
|
||
|
||
### Audit Integrity
|
||
|
||
- Hash chain: each entry's SHA-256 covers all fields including `prev_hash` — tampering any entry breaks all subsequent hashes
|
||
- Canonical JSON: `BTreeMap` for deterministic key ordering — hash is reproducible
|
||
- Single-writer lock: `pg_advisory_lock` — prevents concurrent writes from breaking the chain
|
||
- Panic-safe: `catch_unwind` ensures lock release even on panic
|
||
|
||
### Access Control
|
||
|
||
- Channel membership is the only gate — enforced by the relay at every operation
|
||
- REQ handler checks access before subscription registration — no race window for private channel leaks
|
||
- TOCTOU-safe membership operations: all check-then-modify sequences run inside Postgres transactions
|
||
- Approval tokens: UUID (CSPRNG), stored as SHA-256 hash, single-use enforced with `AND status = 'pending'` in UPDATE
|
||
|
||
### Webhook Security
|
||
|
||
- LiveKit webhooks: HMAC-SHA256 of raw body bytes, hex-encoded, constant-time comparison
|
||
- Workflow webhooks: constant-time XOR comparison of stored UUID secret (not HMAC — compares the secret directly, not a body MAC)
|
||
- Outbound webhooks (CallWebhook): SSRF protection + redirects disabled + 1 MiB response cap
|
||
|
||
---
|
||
|
||
## 8. Infrastructure
|
||
|
||
Docker Compose provides the full local development stack. All services include health checks and resource limits.
|
||
|
||
### Services
|
||
|
||
| Service | Image | Port | Purpose |
|
||
|---------|-------|------|---------|
|
||
| Postgres | `postgres:17-alpine` | 5432 | Primary event store — events, channels, tokens, workflows, audit |
|
||
| Redis | `redis:7-alpine` | 6379 | Pub/sub fan-out, presence (SET EX), typing (sorted sets) |
|
||
| Typesense | `typesense/typesense:27.1` | 8108 | Full-text search index |
|
||
| Adminer | `adminer` | 8082 | DB web UI (dev only) |
|
||
| Keycloak | `quay.io/keycloak/keycloak:26` | 8180 | Local OAuth/OIDC stand-in for Okta |
|
||
| MinIO | `minio/minio` | 9000 (API), 9001 (console) | S3-compatible object storage (media) |
|
||
| Prometheus | `prom/prometheus` | 9090 | Metrics collection |
|
||
|
||
### Postgres Schema (key tables)
|
||
|
||
| Table | Purpose |
|
||
|-------|---------|
|
||
| `events` | All stored Nostr events; monthly range-partitioned by `PARTITION BY RANGE` on `created_at` |
|
||
| `channels` | Channel records (type, visibility, canvas, topic) |
|
||
| `channel_members` | Membership with roles; soft-delete via `removed_at` |
|
||
| `workflows` | Workflow definitions (YAML stored as canonical JSON) |
|
||
| `workflow_runs` | Execution records with trigger context and trace |
|
||
| `workflow_approvals` | Approval gates (token stored as SHA-256 hash) |
|
||
| `api_tokens` | API token records (hash only, never plaintext) |
|
||
| `audit_log` | Hash-chain audit entries |
|
||
| `delivery_log` | Delivery tracking (partitioned; Rust module pending) |
|
||
|
||
### Redis Key Patterns
|
||
|
||
| Pattern | Type | TTL | Purpose |
|
||
|---------|------|-----|---------|
|
||
| `sprout:channel:{uuid}` | Pub/Sub channel | — | Event fan-out |
|
||
| `sprout:presence:{pubkey_hex}` | String | 90s | Online/away status |
|
||
| `sprout:typing:{channel_uuid}` | Sorted Set | 60s | Active typers (5s window) |
|
||
|
||
### Typesense Collection
|
||
|
||
Single collection (`events` by default, configurable via `TYPESENSE_COLLECTION`). Schema: `id`, `content`, `kind` (int32), `pubkey` (facet), `channel_id` (facet, optional), `created_at` (int64, default sort), `tags_flat` (string[]).
|
||
|
||
---
|
||
|
||
## 9. Known Limitations
|
||
|
||
These are verified gaps in the current implementation — not design aspirations.
|
||
|
||
| # | Limitation | Detail |
|
||
|---|-----------|--------|
|
||
| 1 | **No sqlx offline query cache** | Uses `sqlx::query()` (runtime) not `sqlx::query!()` (compile-time). No `.sqlx/` directory. Queries are not validated at compile time. |
|
||
| 2 | **No rate limiting implementation** | `RateLimiter` trait exists in `sprout-auth`. Only implementation is `AlwaysAllowRateLimiter` (test stub, gated behind `#[cfg(any(test, feature = "test-utils"))]`). `RateLimitConfig` defines 4 tiers (human, agent-standard, agent-elevated, agent-platform) but none are enforced. |
|
||
| 3 | **No dedicated typing REST endpoint** | Typing indicators (kind 20002) are delivered via both local fan-out and Redis pub/sub (cross-node). There is no REST endpoint to query current typers — `/api/presence` returns online/away status only, not typing state. |
|
||
| 4 | **sprout-huddle is scaffolding** | `sprout-huddle` defines types, token generation, and webhook parsing, but relay-side lifecycle event emission is not implemented. Huddle state events are not wired into the relay's event pipeline. `sprout-proxy` is now functional — see its section above. |
|
||
| 5 | **Approval gates not wired end-to-end** | The executor returns `StepResult::Suspended` and the relay has grant/deny API endpoints with DB CRUD, but the engine intercepts before creating `WaitingApproval` rows — runs that hit an approval gate are marked as Failed (🚧 WF-08). |
|
||
| 6 | **Workflow actions partially stubbed** | `send_dm` and `set_channel_topic` actions log intent but do not emit events (🚧 WF-07). |
|
||
|
||
---
|
||
|
||
## Appendix: LOC Summary
|
||
|
||
| Crate | LOC | Layer |
|
||
|-------|-----|-------|
|
||
| sprout-core | 1,196 | Foundation |
|
||
| sprout-auth | 2,310 | Foundation |
|
||
| sprout-db | 7,367 | Foundation |
|
||
| sprout-pubsub | 887 | Foundation |
|
||
| sprout-search | 1,126 | Foundation |
|
||
| sprout-audit | 776 | Foundation |
|
||
| sprout-workflow | 4,012 | Foundation |
|
||
| sprout-proxy | 4,933 | Client compatibility |
|
||
| sprout-huddle | 728 | Standalone |
|
||
| sprout-relay | 14,327 | Server |
|
||
| sprout-mcp | 4,879 | Agent API |
|
||
| sprout-acp | 14,920 | Agent harness |
|
||
| sprout-sdk | 1,237 | Shared library |
|
||
| sprout-media | 977 | Media storage |
|
||
| sprout-cli | 2,919 | Tooling |
|
||
| sprout-admin | 213 | Tooling |
|
||
| sprout-test-client | 9,319 | Tooling |
|
||
| **Total** | **~72,126** | |
|
||
|
||
*LOC counted with `find crates -name '*.rs' | xargs wc -l`. Includes tests. Measured 2026-04-05.*
|
||
|
||
|