215 lines
8.3 KiB
Markdown
215 lines
8.3 KiB
Markdown
# Orchestration Service
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**Package:** `@nexusai/orchestration-service`
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**Location:** `packages/orchestration-service`
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**Deployed on:** Mini PC 2 (192.168.0.205)
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**Port:** 4000
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## Purpose
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The main entry point for all clients. Assembles context packages from
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memory, routes prompts to inference, and writes new episodes back to
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memory after each interaction. Clients never talk directly to the memory
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or inference services — all traffic flows through orchestration.
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## Dependencies
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- `express` — HTTP API
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- `cors` — cross-origin resource sharing middleware
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- `dotenv` — environment variable loading
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- `@nexusai/shared` — shared utilities
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## Environment Variables
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| Variable | Required | Default | Description |
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|---|---|---|---|
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| PORT | No | 4000 | Port to listen on |
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| MEMORY_SERVICE_URL | No | http://localhost:3002 | Memory service URL |
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| EMBEDDING_SERVICE_URL | No | http://localhost:3003 | Embedding service URL |
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| INFERENCE_SERVICE_URL | No | http://localhost:3001 | Inference service URL |
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| LLAMA_SERVER_URL | No | http://localhost:8080 | Direct llama-server URL for /models/props |
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| QDRANT_URL | No | http://localhost:6333 | Qdrant URL for semantic search |
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| CORS_ORIGIN | No | http://localhost:5173 | Allowed origin for CORS requests |
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| MODELS_MANIFEST_PATH | No | — | Legacy — superseded by `modelsFolderPath` in settings.json |
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## Internal Structure
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```
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src/
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├── services/
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│ ├── memory.js # HTTP client for memory service
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│ ├── inference.js # HTTP client for inference service
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│ ├── embedding.js # HTTP client for embedding service
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│ └── qdrant.js # HTTP client for Qdrant (direct vector search)
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├── chat/
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│ └── index.js # Core pipeline — context assembly, isolation, auto-naming
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├── config/
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│ └── settings.js # Settings load/save — reads/writes data/settings.json
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├── routes/
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│ ├── chat.js # POST /chat and POST /chat/stream
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│ ├── sessions.js # Session CRUD proxy
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│ ├── projects.js # Project CRUD proxy — passes req.body straight through
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│ ├── episodes.js # Episode list and delete proxy
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│ ├── settings.js # GET /settings and PATCH /settings
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│ ├── health.js # GET /health — pings all four services
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│ └── models.js # GET /models — scans .gguf files live, merges with models.json
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# GET /models/props — context window + loaded model from llama-server
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└── index.js # Express app entry point
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```
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The `services/` layer wraps all downstream HTTP calls in named functions.
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URL or endpoint changes have a single place to be updated.
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## Settings
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Settings are persisted to `data/settings.json` and loaded on every request
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via `appSettings.load()` — changes apply immediately without a service restart.
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| Setting | Default | Description |
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| `recentEpisodeLimit` | 5 | Recent episodes injected into prompt |
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| `semanticLimit` | 5 | Semantic search results injected into prompt |
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| `scoreThreshold` | 0.75 | Minimum similarity score for semantic results |
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| `modelsFolderPath` | `/mnt/nexus-models` | Path to folder containing .gguf files |
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| `temperature` | 0.7 | Inference temperature |
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| `repeatPenalty` | 1.1 | Repeat token penalty |
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| `topP` | 0.9 | Nucleus sampling probability mass |
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| `topK` | 40 | Top-K token candidates per step |
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| `systemPrompt` | *(ORCHESTRATION.SYSTEM_PROMPT)* | Global system prompt. `null` reverts to hardcoded constant. |
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Defaults are defined in `config/settings.js` and fall back to constants in
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`@nexusai/shared`. Values saved in `settings.json` take precedence.
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## Chat Pipeline
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Both `POST /chat` and `POST /chat/stream` share the same steps. The only
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difference is how the inference response is delivered to the client.
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### Steps
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1. **Session resolution** — look up session by `externalId`. Auto-create if
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not found. Clients generate a UUID for new conversations — no pre-creation
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step needed.
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2. **Project context resolution** — if the session has a `project_id`, fetch
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the project and all its session IDs. Used to scope semantic search. The
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project's `system_prompt` is also read at this step if set.
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3. **System prompt resolution** — three-tier hierarchy:
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- `project.system_prompt` — if the session is in a project and it's set (highest priority)
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- `settings.systemPrompt` — global setting from `settings.json`
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- `ORCHESTRATION.SYSTEM_PROMPT` — hardcoded constant in `@nexusai/shared` (last resort)
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4. **Recent episode retrieval** — fetch the most recent episodes for the
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session (`recentEpisodeLimit`, default 5).
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5. **Semantic search** — embed the user message, query Qdrant for the top
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most similar past episodes (`semanticLimit`, `scoreThreshold`). Deduplicated
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against recent episodes. Non-critical — if it fails, pipeline continues with
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recency-only context.
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6. **Entity search** — query the `entities` Qdrant collection filtered by
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`projectId`. Non-project sessions receive no entity context. Non-critical.
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7. **Prompt assembly** — combine resolved system prompt, entity context,
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semantic episodes, recent episodes, and user message.
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8. **Inference** — send to inference service with settings-derived parameters
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(temperature, topP, topK, repeatPenalty). `/chat` awaits full response;
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`/chat/stream` pipes SSE chunks to the client.
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9. **Episode write** — write the exchange back to memory with `projectId`.
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Fire-and-forget for `/chat`; awaited for `/chat/stream`.
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10. **Auto-naming** — on `isFirstMessage && !session.name`, fire a secondary
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inference call with a naming prompt (max 20 tokens, temperature 0.3) and
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write the result back as `session.name`. Fully fire-and-forget.
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### Prompt Structure
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```
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[Resolved system prompt]
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Here is what you know about entities relevant to this conversation:
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- {name} ({type}): {notes}
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... (up to 5 entity results)
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---
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Here are some relevant memories from earlier conversations:
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User: {past user message}
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Assistant: {past ai response}
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... (up to semanticLimit semantic episodes)
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---
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Here are some relevant memories from your past conversations:
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User: {past user message}
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Assistant: {past ai response}
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... (up to recentEpisodeLimit recent episodes)
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--- End of recent memories ---
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User: {current message}
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Assistant:
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```
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Entity context appears first — before episodic memory — because structured
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facts about known entities are the most stable and reliable context. Semantic
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episodes follow, then recent episodes as the immediate conversation flow.
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## SSE Stream Format
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Inference service → orchestration:
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```
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data: {"response":"Hello","done":false}
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data: {"done":true,"model":"gemma-4-26B...gguf","tokenCount":42}
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data: [DONE]
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```
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Orchestration → client:
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```
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data: {"text":"Hello"}
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data: {"done":true,"model":"gemma-4-26B...gguf","tokenCount":42}
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```
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The `[DONE]` sentinel is consumed internally and not forwarded. The stream
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is terminated by `res.end()` after the done event.
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## Models Route
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`GET /models` scans `.gguf` files live on each request from `modelsFolderPath`
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(read from settings). Merges results with a `models.json` file in the same
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folder for richer metadata (label, description). Returns file size in GB.
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`GET /models/props` fetches directly from llama-server via `LLAMA_SERVER_URL`.
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Returns `{ contextWindow, modelAlias }`. `n_ctx` is at
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`data.default_generation_settings.n_ctx` in the llama-server response.
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Returns `503` if llama-server is unreachable.
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## Sessions Route Behaviour
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`PATCH /sessions/:sessionId` accepts either `name`, `projectId`, or both.
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The validation guard only rejects requests where neither is provided:
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```js
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if (!name?.trim() && projectId === undefined) {
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return res.status(400).json({ error: 'name or projectId is required' });
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}
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```
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This allows `useChat` to write project assignment separately from rename
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operations.
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## Caddy Configuration
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Each route prefix needs a handle block in the Caddyfile on Mini PC 2:
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```
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handle /chat* { reverse_proxy localhost:4000 }
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handle /sessions* { reverse_proxy localhost:4000 }
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handle /models* { reverse_proxy localhost:4000 }
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handle /projects* { reverse_proxy localhost:4000 }
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handle /episodes* { reverse_proxy localhost:4000 }
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handle /settings* { reverse_proxy localhost:4000 }
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handle /health* { reverse_proxy localhost:4000 }
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```
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After updating: `caddy reload --config /path/to/Caddyfile`
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For all HTTP endpoints, see `api-routes.md`. |