yarp

name	yarp
description	Configures YARP reverse proxy for API gateway routing. Use when: Setting up API gateway routes, configuring path transformations, proxying requests to backend services, or aggregating microservice endpoints.
allowed-tools	Read, Edit, Write, Glob, Grep, Bash, mcp__context7__resolve-library-id, mcp__context7__query-docs

YARP Skill

YARP (Yet Another Reverse Proxy) is the .NET reverse proxy used for API gateway routing in Sorcha. The gateway routes external requests to internal microservices while handling path transformations, security headers, and CORS. Key pattern: gateway-specific endpoints execute BEFORE MapReverseProxy() which must be called last.

Quick Start

Basic Setup

// Program.cs - Add YARP with configuration-based routes
builder.Services.AddReverseProxy()
    .LoadFromConfig(builder.Configuration.GetSection("ReverseProxy"));

// CRITICAL: MapReverseProxy() must be called LAST
app.MapReverseProxy();

Route Configuration

{
  "ReverseProxy": {
    "Routes": {
      "blueprint-route": {
        "ClusterId": "blueprint-cluster",
        "Match": { "Path": "/api/blueprint/{**catch-all}" },
        "Transforms": [{ "PathPattern": "/api/{**catch-all}" }]
      }
    },
    "Clusters": {
      "blueprint-cluster": {
        "Destinations": {
          "destination1": { "Address": "http://blueprint-service:8080" }
        }
      }
    }
  }
}

Key Concepts

Concept	Usage	Example
Route	Maps external path to cluster	"Path": "/api/blueprint/{**catch-all}"
Cluster	Backend service destination(s)	"Address": "http://service:8080"
Transform	Rewrites path before forwarding	"PathPattern": "/api/{**catch-all}"
Catch-all	Captures remaining path segments	{**catch-all} or {*any}

Common Patterns

Path Prefix Stripping

When: External API has service prefix, backend doesn't

{
  "Match": { "Path": "/api/blueprint/{**catch-all}" },
  "Transforms": [{ "PathPattern": "/api/{**catch-all}" }]
}

Request: GET /api/blueprint/blueprints → Backend: GET /api/blueprints

Health Endpoint Mapping

When: Unified health checks across services

{
  "blueprint-status-route": {
    "ClusterId": "blueprint-cluster",
    "Match": { "Path": "/api/blueprint/status" },
    "Transforms": [{ "PathPattern": "/api/health" }]
  }
}

X-Forwarded Headers

When: Backend needs original client info

"Transforms": [
  { "PathPattern": "/api/{**catch-all}" },
  { "X-Forwarded": "Set" }
]

See Also

• patterns - Route patterns and transformations
• workflows - Setup and testing workflows

Related Skills

• See the aspire skill for service discovery integration
• See the minimal-apis skill for gateway-specific endpoints
• See the jwt skill for authentication pass-through
• See the docker skill for container networking

Documentation Resources

Fetch latest YARP documentation with Context7.

How to use Context7:

1. Use mcp__context7__resolve-library-id to search for "yarp"
2. Query with mcp__context7__query-docs using the resolved library ID

Library ID: /dotnet/yarp

Recommended Queries:

• "YARP configuration routes clusters transforms"
• "YARP load balancing health checks"
• "YARP request transforms path rewriting"