CLAUDE.md

@@ -10,10 +10,16 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 go build -o kvs .
 
 # Run with default config (auto-generates config.yaml)
-./kvs
+./kvs start config.yaml
 
 # Run with custom config
-./kvs /path/to/config.yaml
+./kvs start /path/to/config.yaml
+
+# Check running instances
+./kvs status
+
+# Stop instance
+./kvs stop config
 
 # Run comprehensive integration tests
 ./integration_test.sh
@@ -25,6 +31,32 @@ go run test_conflict.go data1 data2
 go build -o kvs . && ./integration_test.sh
 ```
 
+### Process Management Commands
+```bash
+# Start as background daemon
+./kvs start <config.yaml>       # .yaml extension optional
+
+# Stop daemon
+./kvs stop <config>             # Graceful SIGTERM shutdown
+
+# Restart daemon
+./kvs restart <config>          # Stop then start
+
+# Show status
+./kvs status                    # All instances
+./kvs status <config>           # Specific instance
+
+# Run in foreground (for debugging)
+./kvs <config.yaml>             # Logs to stdout, blocks terminal
+
+# View daemon logs
+tail -f ~/.kvs/logs/kvs_<config>.yaml.log
+
+# Global state directories
+~/.kvs/pids/                    # PID files (works from any directory)
+~/.kvs/logs/                    # Daemon log files
+```
+
 ### Development Workflow
 ```bash
 # Format and check code
@@ -38,11 +70,25 @@ go mod tidy
 go build .
 
 # Test specific cluster scenarios
-./kvs node1.yaml &  # Terminal 1
-./kvs node2.yaml &  # Terminal 2
+./kvs start node1.yaml
+./kvs start node2.yaml
+
+# Wait for cluster formation
+sleep 5
+
+# Test data operations
 curl -X PUT http://localhost:8081/kv/test/data -H "Content-Type: application/json" -d '{"test":"data"}'
 curl http://localhost:8082/kv/test/data  # Should replicate within ~30 seconds
-pkill kvs
+
+# Check daemon status
+./kvs status
+
+# View logs
+tail -f ~/.kvs/logs/kvs_node1.yaml.log
+
+# Cleanup
+./kvs stop node1
+./kvs stop node2
 ```
 
 ## Architecture Overview
@@ -58,7 +104,8 @@ KVS is a **distributed, eventually consistent key-value store** built around thr
 
 #### Modular Package Design
 - **`auth/`** - Complete JWT authentication system with POSIX-inspired permissions
-- **`cluster/`** - Distributed systems logic (gossip, sync, merkle trees)  
+- **`cluster/`** - Distributed systems logic (gossip, sync, merkle trees)
+- **`daemon/`** - Process management (daemonization, PID files, lifecycle)
 - **`storage/`** - BadgerDB abstraction with compression and revision history
 - **`server/`** - HTTP handlers, routing, and lifecycle management
 - **`features/`** - Utility functions for TTL, rate limiting, tamper logging, backup
@@ -147,9 +194,18 @@ Creates two BadgerDB instances with intentionally conflicting data (same path, s
 - **Bootstrap sync**: Up to 30 days of historical data for new nodes
 
 #### Main Entry Point Flow
-1. `main.go` loads config (auto-generates default if missing)
-2. `server.NewServer()` initializes all subsystems
-3. Graceful shutdown handling with `SIGINT`/`SIGTERM`
-4. All business logic delegated to modular packages
+1. `main.go` parses command-line arguments for subcommands (`start`, `stop`, `status`, `restart`)
+2. For daemon mode: `daemon.Daemonize()` spawns background process and manages PID files
+3. For server mode: loads config (auto-generates default if missing)
+4. `server.NewServer()` initializes all subsystems
+5. Graceful shutdown handling with `SIGINT`/`SIGTERM`
+6. All business logic delegated to modular packages
+
+#### Daemon Architecture
+- **PID Management**: Global PID files stored in `~/.kvs/pids/` for cross-directory access
+- **Logging**: Daemon logs written to `~/.kvs/logs/{config-name}.log`
+- **Process Lifecycle**: Spawns detached process via `exec.Command()` with `Setsid: true`
+- **Config Normalization**: Supports both `node1` and `node1.yaml` formats
+- **Stale PID Detection**: Checks process existence via `Signal(0)` before operations
 
 This architecture enables easy feature addition, comprehensive testing, and reliable operation in distributed environments while maintaining simplicity for single-node deployments.

README.md

@@ -69,11 +69,67 @@ go build -o kvs .
 
 ### Quick Test
 ```bash
-# Start standalone node
-./kvs
+# Start standalone node (uses config.yaml if it exists, or creates it)
+./kvs start config.yaml
 
 # Test the API
 curl http://localhost:8080/health
+
+# Check status
+./kvs status
+
+# Stop when done
+./kvs stop config
+```
+
+## 🎮 Process Management
+
+KVS includes systemd-style daemon commands for easy process management:
+
+```bash
+# Start as background daemon
+./kvs start config.yaml      # or just: ./kvs start config
+./kvs start node1.yaml       # Start with custom config
+
+# Check status
+./kvs status                 # Show all running instances
+./kvs status node1           # Show specific instance
+
+# Stop daemon
+./kvs stop node1             # Graceful shutdown
+
+# Restart daemon
+./kvs restart node1          # Stop and start
+
+# Run in foreground (traditional)
+./kvs node1.yaml             # Logs to stdout
+```
+
+### Daemon Features
+- **Global PID tracking**: PID files stored in `~/.kvs/pids/` (works from any directory)
+- **Automatic logging**: Logs written to `~/.kvs/logs/{config-name}.log`
+- **Flexible naming**: Config extension optional (`node1` or `node1.yaml` both work)
+- **Graceful shutdown**: SIGTERM sent for clean shutdown
+- **Stale PID cleanup**: Automatically detects and cleans dead processes
+- **Multi-instance**: Run multiple KVS instances on same machine
+
+### Example Workflow
+```bash
+# Start 3-node cluster as daemons
+./kvs start node1.yaml
+./kvs start node2.yaml
+./kvs start node3.yaml
+
+# Check cluster status
+./kvs status
+
+# View logs
+tail -f ~/.kvs/logs/kvs_node1.yaml.log
+
+# Stop entire cluster
+./kvs stop node1
+./kvs stop node2
+./kvs stop node3
 ```
 
 ## ⚙️ Configuration
@@ -308,17 +364,23 @@ clustering_enabled: true
 
 #### Start the Cluster
 ```bash
-# Terminal 1
-./kvs node1.yaml
-
-# Terminal 2 (wait a few seconds)
-./kvs node2.yaml
-
-# Terminal 3 (wait a few seconds)
-./kvs node3.yaml
+# Start as daemons
+./kvs start node1.yaml
+sleep 2
+./kvs start node2.yaml
+sleep 2
+./kvs start node3.yaml
 
 # Verify cluster formation
 curl http://localhost:8081/members/  # Should show all 3 nodes
+
+# Check daemon status
+./kvs status
+
+# Stop cluster when done
+./kvs stop node1
+./kvs stop node2
+./kvs stop node3
 ```
 
 ## 🔄 How It Works
@@ -364,9 +426,10 @@ go build -o kvs .
 ./integration_test.sh
 
 # Manual basic functionality test
-./kvs &
+./kvs start config.yaml
+sleep 2
 curl http://localhost:8080/health
-pkill kvs
+./kvs stop config
 
 # Manual cluster test (requires creating configs)
 echo 'node_id: "test1"
@@ -379,8 +442,9 @@ port: 8082
 seed_nodes: ["127.0.0.1:8081"]
 auth_enabled: false' > test2.yaml
 
-./kvs test1.yaml &
-./kvs test2.yaml &
+./kvs start test1.yaml
+sleep 2
+./kvs start test2.yaml
 
 # Test data replication (wait for cluster formation)
 sleep 10
@@ -393,7 +457,8 @@ sleep 30
 curl http://localhost:8082/kv/test/data
 
 # Cleanup
-pkill kvs
+./kvs stop test1
+./kvs stop test2
 rm test1.yaml test2.yaml
 ```
 
@@ -418,17 +483,22 @@ auth_enabled: false
 log_level: "debug"' > conflict2.yaml
 
 # Start nodes with conflicting data
-./kvs conflict1.yaml &
-./kvs conflict2.yaml &
+./kvs start conflict1.yaml
+sleep 2
+./kvs start conflict2.yaml
 
 # Watch logs for conflict resolution
+tail -f ~/.kvs/logs/kvs_conflict1.yaml.log ~/.kvs/logs/kvs_conflict2.yaml.log &
+
 # Both nodes will converge within ~10-30 seconds
 # Check final state
 sleep 30
 curl http://localhost:9111/kv/test/conflict/data
 curl http://localhost:9112/kv/test/conflict/data
 
-pkill kvs
+# Cleanup
+./kvs stop conflict1
+./kvs stop conflict2
 rm conflict1.yaml conflict2.yaml
 ```
 
@@ -474,6 +544,10 @@ kvs/
 ├── config/                    # Configuration management
 │   └── config.go             # Config loading & defaults
 │
+├── daemon/                    # Process management
+│   ├── daemonize.go          # Background process spawning
+│   └── pid.go                # PID file management
+│
 ├── features/                  # Utility features
 │   ├── auth.go               # Auth utilities
 │   ├── backup.go             # Backup system
@@ -580,8 +654,9 @@ type StoredValue struct {
 ## 🛡️ Production Considerations
 
 ### Deployment
-- Use systemd or similar for process management
-- Configure log rotation for JSON logs
+- Built-in daemon commands (`start`/`stop`/`restart`/`status`) for process management
+- Alternatively, use systemd or similar for advanced orchestration
+- Logs automatically written to `~/.kvs/logs/` (configure log rotation)
 - Set up monitoring for `/health` endpoint
 - Use reverse proxy (nginx/traefik) for TLS and load balancing