MemRec Daemon — AI Memory Persistence Server

The daemon server for MemRec AI memory persistence system, providing persistent storage, semantic search, and project isolation.

Overview

memrecd is the core server component of the MemRec ecosystem. It runs as a background daemon, exposing a JSON-RPC 2.0 API over Unix socket for memory operations, semantic search, and project management.

Features

• Persistent Storage: RocksDB-based storage for metadata and vector embeddings
• Semantic Search: Vector similarity search using ONNX models (MiniLM-L6-v2, BGE-M3)
• Project Isolation: Separate memory spaces per project with automatic detection
• Unix Socket API: JSON-RPC 2.0 interface for local communication
• Importance Scoring: Automatic importance calculation based on recency, access count, and relevance
• Chunked Storage: Support for large memories with automatic chunking
• Embedding Generation: Integration with fastembed for efficient embeddings

Installation

From crates.io (Recommended)

cargo install --locked memrecd

Using mr-install (All-in-one)

cargo install --locked mr-install
mr-install

Usage

Starting the Daemon

# Start the daemon (will run in background)
memrecd

# Start with verbose logging
RUST_LOG=debug memrecd

# Check daemon status
systemctl --user status memrecd  # Linux
launchctl list cn.itcraft.memrecd  # macOS

Configuration

The daemon reads configuration from ~/.memrec/config.toml:

version = "0.3.0"

[model]
model_type = "minilm-l6-v2"  # or "bge-m3"
source = "huggingface"
dimension = 384  # 1024 for BGE-M3

[server]
socket_path = "~/.memrec/memrecd.sock"
data_dir = "~/.memrec/data"
vector_dir = "~/.memrec/vectors"
log_path = "~/.memrec/memrecd.log"

# Model files with SHA256 hashes for security
[[model.files]]
filename = "model.onnx"
sha256 = "bbd7b466f6d58e646fdc2bd5fd67b2f5e93c0b687011bd4548c420f7bd46f0c5"
required = true

[[model.files]]
filename = "tokenizer.json"
sha256 = "da0e79933b9ed51798a3ae27893d3c5fa4a201126cef75586296df9b4d2c62a0"
required = true

Architecture

┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│   Unix Socket   │────▶│   JSON-RPC 2.0  │────▶│  Request Router │
│    Interface    │     │     Handler     │     │                 │
└─────────────────┘     └─────────────────┘     └─────────────────┘
                                                            │
                                                            ▼
┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│  Vector Store   │◀───▶│  Embedding Gen  │◀───▶│   Model Config  │
│   (RocksDB)     │     │   (fastembed)   │     │                 │
└─────────────────┘     └─────────────────┘     └─────────────────┘
        │                        │                        │
        ▼                        ▼                        ▼
┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│  Metadata Store │     │  Project Detect │     │   Importance    │
│   (RocksDB)     │     │   (.mr_pid)     │     │   Calculator    │
└─────────────────┘     └─────────────────┘     └─────────────────┘

API Reference

JSON-RPC Methods

The daemon supports the following JSON-RPC 2.0 methods:

Memory Operations

• add_memory - Add a new memory with optional tags and importance
• get_memory - Retrieve a memory by ID
• update_memory - Update an existing memory
• delete_memory - Soft delete a memory
• list_memories - List memories with pagination
• search_memories - Semantic search with relevance scoring

Project Operations

• get_project_info - Get current project information
• set_project - Manually set project context
• list_projects - List all projects

System Operations

• ping - Health check
• stats - Get server statistics
• version - Get server version

Example API Usage

# Using curl to interact with the socket
echo '{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "add_memory",
  "params": {
    "id": "test-123",
    "content": "This is a test memory",
    "mtype": "conversation",
    "tags": ["test", "example"],
    "importance": 0.8
  }
}' | socat UNIX-CONNECT:$HOME/.memrec/memrecd.sock STDIO

Development

Building from Source

# Clone repository
git clone https://github.com/itcraft-cn/memrec
cd memrec

# Build in release mode
cargo build --release --bin memrecd

# Run tests
cargo test --release --bin memrecd

Running Tests

# Run all tests
cargo test --release

# Run specific test categories
cargo test --release --test embedding
cargo test --release --test storage
cargo test --release --test server

Logging

The daemon uses tracing for structured logging:

# Different log levels
RUST_LOG=error memrecd     # Only errors
RUST_LOG=warn memrecd      # Warnings and errors
RUST_LOG=info memrecd      # Info level (default)
RUST_LOG=debug memrecd     # Debug information
RUST_LOG=trace memrecd     # Verbose tracing

Performance

Memory Usage

• Metadata: ~50 bytes per memory entry
• Vectors: 384 bytes (MiniLM-L6-v2) or 1024 bytes (BGE-M3) per memory
• Index: Additional ~20% overhead for vector indices

Throughput

• Embedding: ~1000 texts/second on CPU
• Search: ~10,000 vectors/second for nearest neighbor search
• Storage: ~10,000 writes/second for metadata

Scalability

• Supports millions of memories per project
• Automatic memory chunking for large contents
• Background importance recalculation

Security

Data Protection

• Project isolation prevents cross-project data access
• Unix socket permissions restrict access to owner
• Configuration files are user-mode only (600 permissions)

Model Security

• SHA256 hash verification for downloaded models
• Optional --skip-hash-verify flag with security warnings
• Support for trusted mirrors with hash validation

Service Security

• Runs as user service (not root)
• No network exposure by default
• Hardened service configuration files

Troubleshooting

Common Issues

1. Socket Connection Failed

   # Check if daemon is running
   ps aux | grep memrecd
   
   # Check socket permissions
   ls -la ~/.memrec/memrecd.sock
   
   # Restart daemon
   systemctl --user restart memrecd
   

2. Model Download Failed

   # Check network connectivity
   curl -I https://huggingface.co
   
   # Use mirror
   mr-install --use-hf-mirror
   
   # Skip hash verification (security risk)
   mr-install --skip-hash-verify
   

3. Storage Issues

   # Check disk space
   df -h ~/.memrec
   
   # Repair database
   rm -rf ~/.memrec/data
   rm -rf ~/.memrec/vectors
   # Re-run mr-install to recreate
   

Logs

• Service logs: ~/.memrec/memrecd.log
• System logs: journalctl --user -u memrecd (Linux)
• Launchd logs: log stream --predicate 'subsystem == "cn.itcraft.memrecd"' (macOS)

Contributing

See CONTRIBUTING.md for development guidelines.

License

Apache License 2.0 - see LICENSE for details.

Links

• Main Repository
• API Documentation
• Crates.io
• CLI Client
• Installer