examples

Package cluster demonstrates the Cluster Extension point.

Package clusterasyncrouter demonstrates body-driven upstream selection using the async ClusterLBCompletion pattern documented at docs/envoy-dynamic-module-upstream-selection.md (lines 154–235).

Package clusterdfp demonstrates model-based upstream selection with the Cluster Extension.

Package clusterfilterstate demonstrates passing filter state from an HTTP filter to a Cluster Extension.

Package clustergroup demonstrates how to use up.BaseCluster, up.ClusterGroup, and up.RunRetry together to build a cluster extension that discovers upstream hosts from an external source at runtime.

Package clusterleastconn demonstrates the Cluster Extension point with a least-connections load balancer.

Package clusterrouter demonstrates request-aware host selection with a Cluster Extension plus upstream request shaping from Go.

Package clustershardrouter demonstrates request-aware shard selection with a Cluster Extension plus upstream request shaping from Go.

Package grpc_callout demonstrates using up.GRPCCallout to call a rate-limit service (envoy.service.ratelimit.v3.RateLimitService/ShouldRateLimit) from a request body handler.

Package main demonstrates how to wire HostSet and HostRefreshLoop together.

Package lbpolicy demonstrates the LB Policy extension point: Envoy manages the host set via static config or EDS; the module only implements ChooseHost.

Package lbpolicymetadataroute demonstrates capability-based routing using Envoy endpoint filter_metadata.

Package lbpolicyretryaware demonstrates the LB Policy extension point with a retry-aware selection strategy.

Package metadata demonstrates metadata-driven routing: an HTTP filter reads static route filter_metadata, writes the tier to dynamic metadata for access logs, and passes the tier via filter state so the Cluster Extension can pick the correct upstream host.

Package observability is a Transit Envoy dynamic module example that demonstrates observability via the active tracing span (OTEL export path) and dynamic metadata for access logs.

Package requestui is a transit filter that records every request and response into a Postgres database (or in-memory ring buffer) and serves a near-realtime web UI.

Package spa demonstrates serving a Vite + React SPA directly from an Envoy dynamic module — no file system access, no separate web server.

Package ssetap taps an SSE response stream to extract LLM token usage without buffering the full body.

Package tracepropagation is a Transit Envoy dynamic module example that demonstrates W3C trace context propagation through a full four-hop path.

Package wsproxy demonstrates the embedded WebSocket proxy pattern using up.Register + up.WithGroup, with a complete implementation for the OpenAI Responses API WebSocket mode at /v1/responses.