How do you configure EnvoyProxy with a default (catch-all) route for traffic?

Question

See https://www.envoyproxy.io/docs/envoy/latest/api-v2/api/v2/route/route.proto#envoy-api-msg-route-routematch

Assuming you want to have one 'catch-all' or default route in your Envoy Proxy, how do you configure Envoy?  The docs are a bit sparse on exactly what you could do here.

no_longer_in_sudoers_file · Accepted Answer

Let's assume you have two virtual machines on your dev laptop: serviceProxy and proxyTarget.

You can use the following envoy.conf to achieve the goal.

# serviceProxy: 192.168.127.10:{10000,9901}
# proxyTarget: 192.168.127.11:80
#
admin:
 access_log_path: /tmp/admin_access.log
 address:
 socket_address: { address: 0.0.0.0, port_value: 9901 }

static_resources:
 listeners:
 - name: catch_all_proxy_rule
 address:
 socket_address: { address: 0.0.0.0, port_value: 10000 }
 filter_chains:
 - filters:
 - name: envoy.http_connection_manager
 config:
 stat_prefix: ingress_proxyTarget
 route_config:
 name: default_route
 virtual_hosts:
 - name: default_vhost
 domains: ["*"]
 routes:
 - match: { prefix: "" }
 # route: { host_rewrite: proxyTarget.local, cluster: proxyTarget }
 route: { cluster: proxyTarget }
 http_filters:
 - name: envoy.router
 clusters:
 - name: proxyTarget
 connect_timeout: 0.12s
 type: LOGICAL_DNS
 # Comment out the following line to test on v6 networks
 dns_lookup_family: V4_ONLY
 lb_policy: ROUND_ROBIN
 hosts: [{ socket_address: { address: 192.168.127.11, port_value: 80 }}]