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Multi-Tenant Quota Guide

This guide explains quota setup for rule engine and messaging workloads.

1. What is enforced​

Supported quota keys (from QuotaType):

  • RuleExecutionsPerDay
  • ConcurrentExecutions
  • ApiRequestsPerMinute
  • RuleEvaluationsPerSecond
  • WorkflowExecutionsPerHour
  • StorageUsageMB
  • TotalRules
  • TotalDecisionTables
  • TotalWorkflows
  • MessagesPerMinute — enforced by TenantQuotaMessagingFilter on every publish/send
  • MessagesPerDay — enforced by TenantQuotaMessagingFilter on every publish/send

2. Registration​

InfrastructureExtensions already wires quota services:

  • AddTenantQuotaManagement()
  • UseQuotaEnforcement()

3. Runtime behavior​

  • Middleware checks ApiRequestsPerMinute.
  • RuleOrchestrator<TContext> checks and updates:
    • ConcurrentExecutions
    • RuleEvaluationsPerSecond
    • RuleExecutionsPerDay
  • TenantQuotaMessagingFilter checks and updates:
    • MessagesPerMinute (rolling 1-minute window)
    • MessagesPerDay (rolling 24-hour window)
  • On violation, QuotaExceededException is thrown or API returns 429.

Messaging quota note: QuotaExceededException thrown by the messaging filter is not a transient infrastructure error. MassTransit will not retry it — the message is dropped. This is intentional to prevent quota circumvention through retry loops.

4. Tiers​

Preset tiers in TenantQuotaPresets:

  • Free
  • Starter
  • Professional
  • Enterprise

5. Storage and tracker​

  • ITenantQuotaStore stores limits and usage.
  • TenantQuotaTracker uses distributed cache for time-window counters.

6. Messaging quota integration​

Enable per-tenant message rate limiting by combining the quota system with the messaging stack:

"MessageBusConfigs": {
  "EnableQuotaEnforcement": true
}
// Registration
builder.Services.AddTenantQuotaManagement();
builder.Services.AddMessageBus(builder.Configuration, ...);

Define limits per tenant:

await quotaStore.SetAsync(new TenantQuota
{
    TenantId = "tenant-a",
    QuotaType = QuotaType.MessagesPerMinute,
    Limit = 1000
});
await quotaStore.SetAsync(new TenantQuota
{
    TenantId = "tenant-a",
    QuotaType = QuotaType.MessagesPerDay,
    Limit = 50000
});

See Messaging Guide for the full messaging pipeline.

7. Testing​

See tests/Muonroi.BuildingBlock.Test/Tenancy/TenantQuotaTests.cs for baseline coverage.

For messaging-specific quota tests see tests/Muonroi.Messaging.MassTransit.Tests/TenantQuotaMessagingFilterTests.cs.