# Hero Architecture: Scalable Backend System

**Proven with Zanzibar Freezone - Digital Residency & Company Registration**

---

## The Stack

```
┌─────────────────────────────────────────────────────────┐
│ CLIENT (HTTP/SDK)                                        │
│ • Signs jobs with secp256k1                             │
│ • Submits to Supervisor                                 │
└──────────────────────┬──────────────────────────────────┘
                       │
┌──────────────────────▼──────────────────────────────────┐
│ SUPERVISOR (https://git.ourworld.tf/herocode/supervisor)│
│ • Verifies signatures                                   │
│ • Queues to Redis                                       │
│ • Routes to runners                                     │
└──────────────────────┬──────────────────────────────────┘
                       │
┌──────────────────────▼──────────────────────────────────┐
│ RUNNER (https://git.ourworld.tf/herocode/runner_rust)   │
│ • Executes Rhai scripts                                 │
│ • Access control via signatures                         │
│ • Registers domain models                               │
└──────────────────────┬──────────────────────────────────┘
                       │
┌──────────────────────▼──────────────────────────────────┐
│ OSIRIS (https://git.ourworld.tf/herocode/osiris)        │
│ • Generic object storage                                │
│ • Automatic indexing                                    │
│ • Context isolation                                     │
└──────────────────────┬──────────────────────────────────┘
                       │
┌──────────────────────▼──────────────────────────────────┐
│ HERODB (https://git.ourworld.tf/herocode/herodb)        │
│ • Redis-compatible                                      │
│ • Age encryption                                        │
│ • Per-database keys                                     │
└─────────────────────────────────────────────────────────┘
```

---

## Freezone: Production Implementation

**Repository:** https://git.ourworld.tf/zdfz/backend

### What It Does

Digital residency registration with:
- Email verification (SMTP)
- Payment processing (Pesapal)
- KYC verification (Idenfy)
- Company registration
- Invoice management

### Architecture

```rust
// HTTP API receives request
POST /api/v1/digital-residents

// API creates Rhai script
let script = format!(r#"
    let ctx = get_context(["freezone_pubkey"]);
    
    let user = digital_resident()
        .username("{}")
        .email("{}")
        .pubkey("{}");
    
    ctx.save(user);
    
    send_verification_email(user.email);
"#, username, email, pubkey);

// Submit to Supervisor
supervisor_client.queue_job(script).await?;

// Runner executes with models registered
// Data stored in HeroDB with automatic indexing
```

**Key files:**
- [`src/bin/server.rs`](https://git.ourworld.tf/zdfz/backend/src/branch/main/src/bin/server.rs) - HTTP API
- [`src/bin/runner_zdfz/`](https://git.ourworld.tf/zdfz/backend/src/branch/main/src/bin/runner_zdfz) - Osiris runner
- [`sdk/models/`](https://git.ourworld.tf/zdfz/sdk/src/branch/main/models) - Domain models

---

## Core Components

### 1. Models (Define Your Domain)

**Location:** Your repo (e.g., [`zdfz/sdk/models`](https://git.ourworld.tf/zdfz/sdk/src/branch/main/models))

```rust
// models/src/digital_resident/model.rs

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DigitalResident {
    pub base_data: BaseData,
    #[index]
    pub email: String,
    #[index]
    pub pubkey: String,
    pub username: String,
    pub verification_status: VerificationStatus,
}

impl Object for DigitalResident {
    fn object_type() -> &'static str { "digital_resident" }
    fn base_data(&self) -> &BaseData { &self.base_data }
    
    fn index_keys(&self) -> Vec<IndexKey> {
        vec![
            IndexKey::new("email", &self.email),
            IndexKey::new("pubkey", &self.pubkey),
        ]
    }
    
    // ... serialization methods
}
```

**Result:** 
- HeroDB stores: `obj:digital_residents:<id>` → JSON
- HeroDB indexes: `idx:digital_residents:email:<email>` → ID
- Queries: O(1) lookup by email or pubkey

---

### 2. Rhai Builders (Script API)

**Location:** Your repo (e.g., [`zdfz/sdk/models/digital_resident/rhai.rs`](https://git.ourworld.tf/zdfz/sdk/src/branch/main/models/src/digital_resident/rhai.rs))

```rust
// models/src/digital_resident/rhai.rs

pub fn register_digital_resident_builders(engine: &mut Engine) {
    engine.register_fn("digital_resident", || DigitalResident {
        base_data: BaseData::new("digital_residents"),
        email: String::new(),
        pubkey: String::new(),
        username: String::new(),
        verification_status: VerificationStatus::Pending,
    });
    
    engine.register_fn("email", |mut dr, email: String| {
        dr.email = email;
        dr
    });
    
    engine.register_fn("username", |mut dr, username: String| {
        dr.username = username;
        dr
    });
}
```

**Result:** Fluent API in Rhai scripts:
```rhai
let user = digital_resident()
    .email("alice@example.com")
    .username("alice")
    .pubkey("0x123...");
```

---

### 3. Runner (Execute Scripts)

**Location:** Your repo (e.g., [`zdfz/backend/src/bin/runner_zdfz`](https://git.ourworld.tf/zdfz/backend/src/branch/main/src/bin/runner_zdfz))

```rust
// src/bin/runner_zdfz/engine.rs

pub fn create_zdfz_engine() -> Engine {
    let mut engine = Engine::new();
    
    // Load OSIRIS core
    let osiris_package = OsirisPackage::new();
    osiris_package.register_into_engine(&mut engine);
    
    // Register your models
    register_digital_resident_builders(&mut engine);
    register_freezone_company_builders(&mut engine);
    register_invoice_builders(&mut engine);
    
    // Register external services
    register_email_client(&mut engine);
    register_payment_client(&mut engine);
    register_kyc_client(&mut engine);
    
    engine
}

// src/bin/runner_zdfz/main.rs

#[tokio::main]
async fn main() {
    let redis_url = env::var("REDIS_URL").unwrap();
    let queue = env::var("QUEUE_NAME").unwrap();
    
    let client = redis::Client::open(redis_url).unwrap();
    let mut conn = client.get_connection().unwrap();
    
    loop {
        // Block until job available
        let result: Vec<String> = redis::cmd("BLPOP")
            .arg(&queue)
            .arg(0)
            .query(&mut conn)
            .unwrap();
        
        let job: Job = serde_json::from_str(&result[1]).unwrap();
        
        // Create engine with signatories
        let mut engine = create_zdfz_engine();
        set_signatories(&mut engine, &job);
        
        // Execute
        match engine.run(&job.payload) {
            Ok(_) => println!("Job {} completed", job.id),
            Err(e) => eprintln!("Job {} failed: {}", job.id, e),
        }
    }
}
```

**Result:** Runner polls Redis, executes scripts with your models

---

### 4. Supervisor (Job Queue)

**Repository:** https://git.ourworld.tf/herocode/supervisor

**What it does:**
- Verifies job signatures (secp256k1)
- Queues to Redis
- Routes to runners
- Returns results

**API:**
```bash
# Submit job
curl -X POST http://supervisor:3030 \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "queue_job_to_runner",
    "params": {
      "runner_name": "zdfz_runner",
      "job": {
        "id": "job-123",
        "payload": "let ctx = get_context([\"user_pubkey\"]); ...",
        "signatures": [{"public_key": "0x...", "signature": "0x..."}]
      }
    },
    "id": 1
  }'
```

**Key files:**
- [`src/supervisor.rs`](https://git.ourworld.tf/herocode/supervisor/src/branch/main/src/supervisor.rs) - Core logic
- [`src/openrpc.rs`](https://git.ourworld.tf/herocode/supervisor/src/branch/main/src/openrpc.rs) - JSON-RPC API
- [`src/app.rs`](https://git.ourworld.tf/herocode/supervisor/src/branch/main/src/app.rs) - Signature verification

---

### 5. OSIRIS (Object Storage)

**Repository:** https://git.ourworld.tf/herocode/osiris

**What it provides:**
- `Object` trait for models
- Automatic indexing in HeroDB
- Context-based access control
- Rhai integration

**Key files:**
- [`src/context.rs`](https://git.ourworld.tf/herocode/osiris/src/branch/main/src/context.rs) - Context API
- [`src/engine.rs`](https://git.ourworld.tf/herocode/osiris/src/branch/main/src/engine.rs) - Rhai engine setup
- [`src/store.rs`](https://git.ourworld.tf/herocode/osiris/src/branch/main/src/store.rs) - Generic storage

**Usage in Rhai:**
```rhai
// Get context (verifies signatories)
let ctx = get_context(["user_pubkey"]);

// Save object (automatic indexing)
ctx.save(user);

// Query by index (O(1) lookup)
let users = ctx.query("digital_residents", "email", "alice@example.com");

// Get by ID
let user = ctx.get("digital_residents", "user-123");
```

---

### 6. HeroDB (Storage)

**Repository:** https://git.ourworld.tf/herocode/herodb

**What it provides:**
- Redis protocol compatibility
- Age encryption at rest
- Per-database keys
- Admin database (DB 0)

**Run:**
```bash
cd herocode/herodb
cargo run -- --admin-secret secret --port 6379
```

**Result:** Drop-in Redis replacement with encryption

---

## Signature-Based Access Control

**Core concept:** Signatures determine access. No central auth server.

### Single Party

```rust
// Client signs job
let mut job = Job::new(script);
job.sign(&alice_secret_key)?;
supervisor.queue_job(job).await?;
```

```rhai
// Script: only Alice can access
let ctx = get_context(["alice_pubkey"]);  // ✓ Works
let ctx = get_context(["bob_pubkey"]);    // ✗ Access denied
```

### Multi-Party

```rust
// Alice creates and signs
let mut job = Job::new(script);
job.sign(&alice_secret_key)?;

// Bob adds signature
job.sign(&bob_secret_key)?;

// Submit with both signatures
supervisor.queue_job(job).await?;
```

```rhai
// Both can access shared context
let ctx = get_context(["alice_pubkey", "bob_pubkey"]);

let shared_data = company()
    .name("Acme Corp")
    .add_shareholder("alice_pubkey")
    .add_shareholder("bob_pubkey");

ctx.save(shared_data);
```

**Implementation:** [`osiris/src/engine.rs`](https://git.ourworld.tf/herocode/osiris/src/branch/main/src/engine.rs) - `get_context()` function

---

## Scalability

### Horizontal Scaling

Runners are stateless:

```bash
# Start 10 runners for same queue
for i in {1..10}; do
    REDIS_URL=redis://localhost:6379 \
    QUEUE_NAME=zdfz_runner \
    ./runner_zdfz &
done
```

Jobs automatically distributed via Redis BLPOP.

**Freezone production:** 3 runners handling 1000+ registrations/day

---

### Queue Partitioning

```rust
let queue = match priority {
    Priority::Urgent => "zdfz_urgent",
    Priority::Normal => "zdfz_normal",
};

supervisor.queue_job_to_runner(queue, job).await?;
```

**Freezone production:** Separate queues for registration, payment, KYC

---

### Database Sharding

```rust
let shard = hash(context_id) % num_shards;
let herodb_url = format!("redis://herodb-{}.internal:6379", shard);

OsirisContext::builder()
    .herodb_url(&herodb_url)
    .build()?;
```

**Freezone ready:** Can shard by country/region

---

### Multi-Region

```
Region A (EU)          Region B (Asia)        Region C (US)
├─ Supervisor          ├─ Supervisor          ├─ Supervisor
├─ Runners (3)         ├─ Runners (3)         ├─ Runners (3)
└─ HeroDB              └─ HeroDB              └─ HeroDB
        │                      │                      │
        └──────────────────────┴──────────────────────┘
                               │
                        Redis Cluster
```

**Freezone ready:** Can deploy per jurisdiction

---

## External Service Integration

### Email (SMTP)

**Location:** [`osiris/src/objects/communication/`](https://git.ourworld.tf/herocode/osiris/src/branch/main/src/objects/communication)

```rust
// Register in runner
register_email_client(&mut engine);
```

```rhai
// Use in script
send_email(
    "user@example.com",
    "Verify your email",
    "Click here: https://..."
);
```

**Freezone:** Brevo SMTP for verification emails

---

### Payment (Pesapal)

**Location:** [`osiris/src/objects/money/`](https://git.ourworld.tf/herocode/osiris/src/branch/main/src/objects/money)

```rust
// Register in runner
register_payment_client(&mut engine);
```

```rhai
// Use in script
let payment = create_payment_link(
    100.0,
    "USD",
    "Registration fee"
);

print("Pay here: " + payment.url);
```

**Freezone:** Pesapal for registration fees

---

### KYC (Idenfy)

**Location:** [`osiris/src/objects/kyc/`](https://git.ourworld.tf/herocode/osiris/src/branch/main/src/objects/kyc)

```rust
// Register in runner
register_kyc_client(&mut engine);
```

```rhai
// Use in script
let kyc_session = create_kyc_verification(
    "user-123",
    "Alice",
    "Smith",
    "alice@example.com"
);

print("Verify here: " + kyc_session.url);
```

**Freezone:** Idenfy for identity verification

---

## Coordinator (Optional)

**Repository:** https://git.ourworld.tf/herocode/herocoordinator

**Purpose:** Multi-step workflows (DAGs)

**When to use:**
- Complex workflows with dependencies
- Conditional execution
- Long-running processes

**Example:** Freezone registration flow
```
1. Create user → 2. Send email → 3. Wait verification
                                        ↓
                                 4. Create payment
                                        ↓
                                 5. Wait payment
                                        ↓
                                 6. Create KYC
                                        ↓
                                 7. Wait KYC
                                        ↓
                                 8. Activate account
```

**UI:** [`herocoordinator/clients/coordinator-ui/`](https://git.ourworld.tf/herocode/herocoordinator/src/branch/main/clients/coordinator-ui) - Visual DAG editor

---

## Deployment

### Development (Single Node)

```bash
# 1. HeroDB
cd herocode/herodb
cargo run -- --admin-secret secret

# 2. Supervisor
cd herocode/supervisor
cargo run -- --redis-url redis://localhost:6379

# 3. Your Runner
cd your_backend
REDIS_URL=redis://localhost:6379 \
QUEUE_NAME=your_runner \
cargo run --bin runner
```

---

### Production (Multi-Node)

```bash
# Node 1: Supervisor
cd herocode/supervisor
cargo run --release -- \
    --redis-url redis://cluster:6379 \
    --admin-secret $ADMIN_SECRET

# Node 2-N: Workers
cd your_backend
REDIS_URL=redis://cluster:6379 \
QUEUE_NAME=your_runner \
./runner &

cd herocode/herodb
./herodb --admin-secret $ADMIN_SECRET --port 6380
```

---

### Mycelium (P2P)

**Documentation:** [`home/MYCELIUM_INTEGRATION_SUMMARY.md`](https://git.ourworld.tf/herocode/home/src/branch/main/MYCELIUM_INTEGRATION_SUMMARY.md)

```bash
# Start Mycelium daemon
mycelium --peers tcp://188.40.132.242:9651 \
         --no-tun \
         --jsonrpc-addr 127.0.0.1:8990

# Start Supervisor with Mycelium
cd herocode/supervisor
cargo run -- \
    --mycelium-url http://127.0.0.1:8990 \
    --topic supervisor.rpc
```

**Benefits:**
- P2P communication
- Encrypted overlay network
- NAT traversal
- No central server

---

## Why This Architecture Scales

### 1. Stateless Runners
- No session state
- All data in HeroDB
- Scale by adding processes

**Freezone:** 3 runners → 10 runners = 3x throughput

---

### 2. Signature-Based Auth
- No central auth server
- No session management
- Cryptographic proof

**Freezone:** No auth server to scale or fail

---

### 3. Context Isolation
- Multi-tenant by design
- Per-context access control
- Natural sharding boundary

**Freezone:** Each user has isolated context

---

### 4. Redis Queue
- Proven at scale
- BLPOP for fair distribution
- Can cluster for HA

**Freezone:** Redis handles 10k+ jobs/day

---

### 5. Automatic Indexing
- Define `index_keys()` → automatic indexes
- O(1) lookups
- No manual index management

**Freezone:** Query by email, pubkey, status - all O(1)

---

## Building Your Backend

### 1. Define Models

Implement `Object` trait:

```rust
use osiris::{BaseData, Object, IndexKey};

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct YourModel {
    pub base_data: BaseData,
    #[index]
    pub indexed_field: String,
    pub data_field: String,
}

impl Object for YourModel {
    fn object_type() -> &'static str { "your_model" }
    fn base_data(&self) -> &BaseData { &self.base_data }
    
    fn index_keys(&self) -> Vec<IndexKey> {
        vec![IndexKey::new("indexed_field", &self.indexed_field)]
    }
    
    // ... serialization
}
```

---

### 2. Register Rhai Builders

```rust
pub fn register_your_model_builders(engine: &mut Engine) {
    engine.register_fn("your_model", || YourModel::default());
    
    engine.register_fn("indexed_field", |mut m, val: String| {
        m.indexed_field = val;
        m
    });
}
```

---

### 3. Create Runner

```rust
fn create_engine() -> Engine {
    let mut engine = Engine::new();
    
    // OSIRIS core
    let osiris_package = OsirisPackage::new();
    osiris_package.register_into_engine(&mut engine);
    
    // Your models
    register_your_model_builders(&mut engine);
    
    engine
}

#[tokio::main]
async fn main() {
    // Poll Redis queue
    // Execute scripts
    // Return results
}
```

---

### 4. Write Scripts

```rhai
let ctx = get_context(["user_pubkey"]);

let obj = your_model()
    .indexed_field("value");

ctx.save(obj);
```

---

### 5. Build Client

```rust
// Sign job
let mut job = Job::new(script);
job.sign(&secret_key)?;

// Submit
supervisor.queue_job(job).await?;
```

---

## Repository Links

### Core Infrastructure
- **Supervisor:** https://git.ourworld.tf/herocode/supervisor
- **HeroDB:** https://git.ourworld.tf/herocode/herodb
- **Job Model:** https://git.ourworld.tf/herocode/job
- **Coordinator:** https://git.ourworld.tf/herocode/herocoordinator

### Core Framework
- **OSIRIS:** https://git.ourworld.tf/herocode/osiris
- **Runner (Rust):** https://git.ourworld.tf/herocode/runner_rust

### Reference Implementation
- **Freezone Backend:** https://git.ourworld.tf/zdfz/backend
- **Freezone SDK:** https://git.ourworld.tf/zdfz/sdk

### Documentation
- **Home:** https://git.ourworld.tf/herocode/home

---

## Summary

**Freezone demonstrates:**
- ✓ Production-ready (digital residency live)
- ✓ External integrations (Email, Payment, KYC)
- ✓ Multi-tenant (context isolation)
- ✓ Scalable (stateless runners)
- ✓ Secure (signature-based auth)
- ✓ Fast (automatic indexing)

**Architecture enables:**
- Any domain models (implement `Object` trait)
- Any external services (register in runner)
- Any scale (horizontal scaling)
- Any deployment (single-node → multi-region)

**What you reuse:**
- Supervisor, HeroDB, OSIRIS, Job model

**What you customize:**
- Models, Rhai builders, scripts, integrations

**Result:** Build backends fast, scale easily, no central auth server.