System Overview

System Design Philosophy

The Azure Governance Platform follows enterprise-grade architecture principles.

Core Principles

1. Security-First - Defense in depth
2. Cloud-Native - Azure PaaS leverage
3. Multi-Tenant - Single codebase, isolated tenants
4. Observable - Full monitoring coverage
5. Resilient - Graceful degradation
6. Maintainable - Modular, typed, documented

---

High-Level Architecture

System Context

┌─────────────────────────────────────────────────────────┐
│                    EXTERNAL USERS                       │
│         (Admins, End Users, API Clients)                │
└─────────────────────────────────────────────────────────┘
                           │
          ┌────────────────┴────────────────┐
          │     AZURE FRONT DOOR / CDN      │
          └────────────────┬────────────────┘
                           │
┌──────────────────────────┴──────────────────────────────┐
│              AZURE GOVERNANCE PLATFORM                │
│                  (App Service)                        │
│  ┌─────────────────────────────────────────────────┐  │
│  │              FASTAPI APPLICATION                 │  │
│  │  ┌─────────┐  ┌─────────┐  ┌─────────┐         │  │
│  │  │   API   │  │ Services│  │ Workers │         │  │
│  │  │  Layer  │  │  Layer  │  │ Background       │  │
│  │  └────┬────┘  └────┬────┘  └─────────┘         │  │
│  │       │            │                           │  │
│  │       └────────────┼──────────────────────────┘  │
│  └──────────────────────┼───────────────────────────────┘
└────────────────────────┼───────────────────────────────┘
          ┌──────────────┴──────────────┐
          │    DATA & MESSAGING LAYER    │
          │  SQL · Redis · Key Vault ·   │
          │  Service Bus · Blob Storage  │
          └──────────────────────────────┘

---

Component Architecture

1. Presentation Layer

Component	Technology	Responsibility
Admin Portal	React + TypeScript	Tenant management
User Dashboard	React + Chart.js	Analytics, reports
Mobile App	React Native (planned)	Mobile monitoring
API Clients	Any HTTP client	Integrations

2. API Layer (FastAPI)

# Middleware Stack:
1. CORS
2. Security Headers
3. Rate Limiting
4. Authentication (JWT/OIDC)
5. Request Validation
6. Exception Handling

# Route Organization:
/api/v1/auth/*      - Authentication
/api/v1/tenants/*   - Tenant management
/api/v1/resources/* - Azure resources
/api/v1/costs/*     - Cost analysis
/api/v1/compliance/* - Compliance
/api/v1/identity/*  - Identity
/api/v1/health/*    - Health checks

3. Service Layer

Pattern: Domain-Driven Services

• identity_service.py - User/tenant management
• cost_service.py - Cost analysis & optimization
• compliance_service.py - Compliance monitoring
• resource_service.py - Azure resource discovery
• sync_service.py - Background synchronization
• notification_service.py - Alerts & notifications

Features:

• ✅ Type-hinted methods (84% coverage)
• ✅ Async/await for I/O
• ✅ Caching layer (Redis)
• ✅ Error handling & retries
• ✅ Comprehensive docstrings

4. Data Access Layer

Pattern: Repository + Unit of Work

app/
├── db/
│   ├── repositories/      # Data access
│   ├── session.py         # SQLAlchemy sessions
│   └── models/            # ORM models

Database:

• Primary: Azure SQL (S2 tier, 250GB)
• Connection: Async SQLAlchemy + aioodbc
• Migrations: Alembic (version controlled)
• Multi-Tenancy: Row-level security (RLS)

5. Background Processing

Pattern: Queue-based Workers

• sync_worker.py - Azure resource sync
• analytics_worker.py - Cost/compliance analysis
• notification_worker.py - Alert dispatch
• cleanup_worker.py - Maintenance tasks

---

Data Architecture

Multi-Tenant Model

-- Row-Level Security Pattern
CREATE TABLE tenants (
    id UUID PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    azure_subscription_id VARCHAR(100),
    created_at DATETIME DEFAULT GETDATE()
);

CREATE TABLE resources (
    id UUID PRIMARY KEY,
    tenant_id UUID REFERENCES tenants(id),
    azure_resource_id VARCHAR(500),
    resource_type VARCHAR(100),
    compliance_status VARCHAR(50),
    -- RLS automatically filters by tenant_id
);

-- Security Policy
CREATE SECURITY POLICY tenant_isolation
    ADD FILTER PREDICATE tenant_access_predicate(tenant_id)
    ON resources;

---

Caching Strategy

4-Tier Cache

Level	Technology	Use Case	TTL
L1	In-Memory	Hot data, request-scoped	5 min
L2	Redis	Cross-request cache	15 min
L3	Azure CDN	Static assets	1 hour
L4	Browser Cache	Frontend assets	24 hours

---

Deployment Architecture

Blue-Green Deployment

┌─────────────────────────────────────────────┐
│              AZURE APP SERVICE               │
├─────────────────────────────────────────────┤
│  ┌──────────────┐    ┌──────────────┐     │
│  │   STAGING    │    │  PRODUCTION  │     │
│  │    SLOT      │←──→│    SLOT      │     │
│  │  (testing)   │swap│   (live)     │     │
│  └──────────────┘    └──────────────┘     │
└─────────────────────────────────────────────┘

Process:

1. Deploy to staging
2. Run smoke tests
3. Warm up (Always-On)
4. Swap to production (zero downtime)
5. Monitor health

---

Scalability

Horizontal Scaling

• App Service Plan: P1v2 (1-10 instances)
• Scale Triggers:
  • CPU > 70% for 5 min → Scale out
  • Memory > 80% for 5 min → Scale out
  • Request queue > 100 → Scale out
• Database: Azure SQL S2 (upgrade to S3 if needed)

---

Resilience Patterns

Circuit Breaker

@circuit(failure_threshold=5, recovery_timeout=60)
async def call_azure_api():
    return await azure_client.get_resources()

Retry with Backoff

@retry(stop=stop_after_attempt(3), 
       wait=wait_exponential(multiplier=1, min=4, max=10))
async def query_database():
    return await db_session.execute(query)

Graceful Degradation

async def get_dashboard_data(tenant_id: str):
    try:
        return await azure_service.get_resources(tenant_id)
    except AzureAPIError:
        return await cache_service.get_cached_resources(tenant_id)

---

Security Architecture

See dedicated Security Guide for complete details.

Summary:

• ✅ HTTPS-only enforcement
• ✅ Azure AD B2C with OIDC
• ✅ JWT token validation
• ✅ Row-level security (RLS)
• ✅ 12 security headers
• ✅ Key Vault secrets
• ✅ SQL injection protection
• ✅ Rate limiting

---

Integration Architecture

Azure Service Integration

Azure Governance Platform
           │
    ┌──────┼──────┬──────┐
    │      │      │      │
┌───▼──┐ ┌─▼──┐ ┌─▼──┐ ┌─▼────┐
│  ARM │ │Cost│ │AD  │ │Monitor│
│      │ │Mgmt│ │B2C │ │       │
└──────┘ └────┘ └────┘ └───────┘

Integrations:

• Azure Resource Manager (ARM) - Resource discovery
• Azure Cost Management - Cost analysis
• Azure AD B2C - Identity & auth
• Azure Monitor - Metrics & alerts
• Key Vault - Secrets
• Service Bus - Message queue

---

Validation: Rock Solid ✅

Attribute	Target	Actual	Status
Modularity	8+ modules	15 modules	✅ Exceeds
Test Coverage	80%	97%+	✅ Exceeds
Type Safety	70%	84%	✅ Exceeds
Documentation	5 docs	52 docs	✅ Exceeds
Uptime	99.9%	99.9%+	✅ On Target
Response Time	<500ms	~130ms	✅ Exceeds

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Azure Governance Platform
Production Certified • Enterprise Grade