Multi Listener Body Pipeline

# Multi-Listener Body Processing Pipeline
#
# Three listeners, each with a different body processing
# strategy. Demonstrates how filter chain composition per
# listener controls body buffering, inspection, and routing
# behavior.
#
# Listener 1 (stream-buffer): Extracts multiple JSON fields
# from the request body in a single parse and routes based
# on the promoted headers. StreamBuffer mode accumulates
# chunks and defers forwarding until extraction completes.
#
# Listener 2 (buffered): Enforces a body size ceiling via
# body_limits.max_request_bytes. Oversized requests receive 413
# before reaching the filter pipeline.
#
# Listener 3 (passthrough): No body inspection. Requests
# are routed by path only, body flows through unmodified
# in streaming mode.
#
# This pattern is common in production gateways that serve
# multiple protocols or tenants with different processing
# requirements on dedicated ports.
#
listeners:
  - name: stream-buffer
    address: "0.0.0.0:8080" # dev value; binds all interfaces
    filter_chains:
      - extract-fields
      - model-routing

  - name: buffered
    address: "0.0.0.0:8081" # dev value; binds all interfaces
    filter_chains:
      - extract-model
      - default-routing

  - name: passthrough
    address: "0.0.0.0:8082" # dev value; binds all interfaces
    filter_chains:
      - default-routing

filter_chains:
  # Multi-field extraction: model for routing, user_id for
  # upstream logging.
  - name: extract-fields
    filters:
      - filter: json_body_field
        fields:
          - field: model
            header: X-Model
          - field: user_id
            header: X-User-Id

  # Single-field extraction for the buffered listener.
  - name: extract-model
    filters:
      - filter: json_body_field
        field: model
        header: X-Model

  # Route by X-Model header when present, fall through to
  # default otherwise.
  - name: model-routing
    filters:
      - filter: router
        routes:
          - path_prefix: "/"
            headers:
              x-model: "model-alpha-1"
            cluster: alpha_cluster
          - path_prefix: "/"
            cluster: default
      - filter: load_balancer
        clusters:
          - name: alpha_cluster
            endpoints:
              - "127.0.0.1:3001"
          - name: default
            endpoints:
              - "127.0.0.1:3000"

  # Path-only routing for passthrough and buffered listeners.
  - name: default-routing
    filters:
      - filter: router
        routes:
          - path_prefix: "/"
            cluster: default
      - filter: load_balancer
        clusters:
          - name: default
            endpoints:
              - "127.0.0.1:3000"

# Body size ceiling: applies to all listeners.
body_limits:
  max_request_bytes: 1048576

insecure_options:
  allow_private_endpoints: true # example proxies to local backends