Add JWT-based authorization support for Temporal server with Keycloak integration

- Create QUICK_REFERENCE.md for a concise guide on setting up temporal authorization.
- Add README_AUTHORIZATION.md detailing the implementation steps and common issues.
- Introduce REVERSE_PROXY_APPROACH.md as an alternative method for authorization using a reverse proxy.
- Implement Dockerfile for building a custom Temporal server with authorization features.
- Add main.go to initialize the custom Temporal server with JWT authorization.
- Create example-keycloak-mapper.json for mapping Keycloak groups to Temporal permissions.
- Add development.yaml for configuring the Temporal server with JWT settings.
- Implement test-authorization.sh script to verify JWT token claims and Temporal server access.
- Include go.mod for managing Go dependencies in the custom server.
- Document troubleshooting steps and customization options in README.md.

custom-server/main.go

@@ -0,0 +1,51 @@
+// Custom Temporal Server with JWT Authorization
+package main
+
+import (
+	"log"
+
+	"go.temporal.io/server/common/authorization"
+	"go.temporal.io/server/common/config"
+	"go.temporal.io/server/temporal"
+)
+
+func main() {
+	// Load Temporal configuration
+	cfg, err := config.LoadConfig("development", "./config", "")
+	if err != nil {
+		log.Fatal("Failed to load config:", err)
+	}
+
+	// Create Temporal server with authorization
+	s, err := temporal.NewServer(
+		temporal.ForServices(temporal.DefaultServices),
+		temporal.WithConfig(cfg),
+		temporal.InterruptOn(temporal.InterruptCh()),
+		
+		// Configure JWT ClaimMapper
+		temporal.WithClaimMapper(func(cfg *config.Config) authorization.ClaimMapper {
+			return authorization.NewDefaultJWTClaimMapper(
+				// Token key provider - fetches public keys from your OIDC provider
+				authorization.NewDefaultTokenKeyProvider(cfg, log.Default()),
+				cfg,
+				log.Default(),
+			)
+		}),
+		
+		// Configure Authorizer
+		temporal.WithAuthorizer(authorization.NewDefaultAuthorizer()),
+	)
+	
+	if err != nil {
+		log.Fatal("Failed to create server:", err)
+	}
+
+	// Start the server
+	log.Println("Starting Temporal Server with JWT Authorization...")
+	err = s.Start()
+	if err != nil {
+		log.Fatal("Server failed:", err)
+	}
+
+	log.Println("Server stopped.")
+}