# Notifier Tenancy Prep — PREP-NOTIFY-TEN-48-001

Status: Implemented (2025-11-27)
Owners: Notifications Service Guild
Scope: Tenancy model and DAL/routes for tenant context in Notifier WebService.

## Overview

Tenant scoping for the Notifier module ensures that rules, templates, incidents, and channels
are isolated per tenant with proper row-level security (RLS) in MongoDB storage.

## Implementation Summary

### 1. Tenant Context Service (`src/Notifier/StellaOps.Notifier.Worker/Tenancy/`)

- **TenantContext.cs**: AsyncLocal-based context propagation for tenant ID and actor
- **TenantServiceExtensions.cs**: DI registration and configuration options
- **ITenantAccessor**: Interface for accessing tenant from HTTP context

Key pattern:
```csharp
// Set tenant context for async scope
using var scope = tenantContext.SetContext(tenantId, actor);
await ProcessEventAsync();

// Or with extension method
await tenantContext.WithTenantAsync(tenantId, actor, async () =>
{
    await ProcessNotificationAsync();
});
```

### 2. Incident Repository (`src/Notify/__Libraries/StellaOps.Notify.Storage.Mongo/`)

New files:
- **Repositories/INotifyIncidentRepository.cs**: Repository interface for incident persistence
- **Repositories/NotifyIncidentRepository.cs**: MongoDB implementation with tenant filtering
- **Serialization/NotifyIncidentDocumentMapper.cs**: BSON serialization for incidents

Key features:
- All queries include mandatory `tenantId` filter
- Document IDs use `{tenantId}:{resourceId}` composite pattern for RLS
- Correlation key lookup scoped to tenant
- Soft delete support with `deletedAt` field

### 3. MongoDB Indexes (tenant-scoped)

Added in `EnsureNotifyIndexesMigration.cs`:
```javascript
// incidents collection
{ tenantId: 1, status: 1, lastOccurrence: -1 }  // Status filtering
{ tenantId: 1, correlationKey: 1, status: 1 }   // Correlation lookup
```

### 4. Existing Tenancy Infrastructure

The following was already in place:
- All models have `TenantId` property (NotifyRule, NotifyChannel, NotifyTemplate, etc.)
- Repository interfaces take `tenantId` as parameter
- Endpoints extract tenant from `X-StellaOps-Tenant` header
- MongoDB document IDs use tenant-prefixed composite keys

## Configuration

```json
{
  "Notifier": {
    "Tenant": {
      "TenantIdHeader": "X-StellaOps-Tenant",
      "ActorHeader": "X-StellaOps-Actor",
      "RequireTenant": true,
      "DefaultActor": "system",
      "ExcludedPaths": ["/health", "/ready", "/metrics", "/openapi"]
    }
  }
}
```

## Usage Examples

### HTTP API
```http
GET /api/v2/rules HTTP/1.1
X-StellaOps-Tenant: tenant-123
X-StellaOps-Actor: user@example.com
```

### Worker Processing
```csharp
public class NotificationProcessor
{
    private readonly ITenantContext _tenantContext;

    public async Task ProcessAsync(NotifyEvent @event)
    {
        using var scope = _tenantContext.SetContext(@event.TenantId, "worker");

        // All subsequent operations are scoped to tenant
        var rules = await _rules.ListAsync(@event.TenantId);
        // ...
    }
}
```

## Handoff Notes

- Incident storage moved from in-memory to MongoDB with full tenant isolation
- Worker should use `ITenantContext.SetContext()` before processing events
- All new repositories MUST include tenant filtering in queries
- Test tenant isolation with multi-tenant integration tests

## Related Files

- `src/Notifier/StellaOps.Notifier.Worker/Tenancy/TenantContext.cs`
- `src/Notifier/StellaOps.Notifier.Worker/Tenancy/TenantServiceExtensions.cs`
- `src/Notify/__Libraries/StellaOps.Notify.Storage.Mongo/Repositories/INotifyIncidentRepository.cs`
- `src/Notify/__Libraries/StellaOps.Notify.Storage.Mongo/Repositories/NotifyIncidentRepository.cs`
- `src/Notify/__Libraries/StellaOps.Notify.Storage.Mongo/Serialization/NotifyIncidentDocumentMapper.cs`
- `src/Notify/__Libraries/StellaOps.Notify.Storage.Mongo/Options/NotifyMongoOptions.cs` (added IncidentsCollection)
- `src/Notify/__Libraries/StellaOps.Notify.Storage.Mongo/Migrations/EnsureNotifyIndexesMigration.cs` (added incident indexes)
- `src/Notify/__Libraries/StellaOps.Notify.Storage.Mongo/ServiceCollectionExtensions.cs` (added INotifyIncidentRepository registration)