const (
    // Authn is the name of the authentication plugin passed through the command line
    Authn = "authn"
    // Authz is the name of the rbac plugin passed through the command line
    Authz = "authz"
    // Health is the name of the health plugin passed through the command line
    Health = "health"
    // Mixer is the name of the mixer plugin passed through the command line
    Mixer = "mixer"
)

type InputParams struct {
    // ListenerProtocol is the protocol/class of listener (TCP, HTTP etc.). Must be set.
    // This is valid only for the inbound listener
    // Outbound listeners could have multiple filter chains, where one filter chain could be
    // a HTTP connection manager with TLS context, while the other could be a tcp proxy with sni
    ListenerProtocol istionetworking.ListenerProtocol
    // ListenerCategory is the type of listener (sidecar_inbound, sidecar_outbound, gateway). Must be set
    ListenerCategory networking.EnvoyFilter_PatchContext

    // Node is the node the response is for.
    Node *model.Proxy
    // ServiceInstance is the service instance colocated with the listener (applies to sidecar).
    ServiceInstance *model.ServiceInstance
    // Service is the service colocated with the listener (applies to sidecar).
    // For outbound TCP listeners, it is the destination service.
    Service *model.Service
    // Port is the port for which the listener is being built
    // For outbound/inbound sidecars this is the service port (not endpoint port)
    // For inbound listener on gateway, this is the gateway server port
    Port *model.Port
    // Bind holds the listener IP or unix domain socket to which this listener is bound
    // if bind is using UDS, the port will be 0 with valid protocol and name
    Bind string

    // Push holds stats and other information about the current push.
    Push *model.PushContext

    // Inbound cluster name. It's only used by newHTTPPassThroughFilterChain.
    // For other scenarios, the field is empty.
    InboundClusterName string
}

type Plugin interface {
    // OnOutboundListener is called whenever a new outbound listener is added to the LDS output for a given service.
    // Can be used to add additional filters on the outbound path.
    OnOutboundListener(in *InputParams, mutable *istionetworking.MutableObjects) error

    // OnInboundListener is called whenever a new listener is added to the LDS output for a given service
    // Can be used to add additional filters.
    OnInboundListener(in *InputParams, mutable *istionetworking.MutableObjects) error

    // OnVirtualListener is called whenever a new virtual listener is added to the
    // LDS output for a given service
    // Can be used to add additional filters.
    OnVirtualListener(in *InputParams, mutable *istionetworking.MutableObjects) error

    // OnOutboundCluster is called whenever a new cluster is added to the CDS output.
    // This is called once per push cycle, and not for every sidecar/gateway, except for gateways with non-standard
    // operating modes.
    OnOutboundCluster(in *InputParams, cluster *xdsapi.Cluster)

    // OnInboundCluster is called whenever a new cluster is added to the CDS output.
    // Called for each sidecar
    OnInboundCluster(in *InputParams, cluster *xdsapi.Cluster)

    // OnOutboundRouteConfiguration is called whenever a new set of virtual hosts (a set of virtual hosts with routes) is
    // added to RDS in the outbound path.
    OnOutboundRouteConfiguration(in *InputParams, routeConfiguration *xdsapi.RouteConfiguration)

    // OnInboundRouteConfiguration is called whenever a new set of virtual hosts are added to the inbound path.
    OnInboundRouteConfiguration(in *InputParams, routeConfiguration *xdsapi.RouteConfiguration)

    // OnInboundFilterChains is called whenever a plugin needs to setup the filter chains, including relevant filter chain
    // configuration, like FilterChainMatch and TLSContext.
    OnInboundFilterChains(in *InputParams) []istionetworking.FilterChain

    // OnInboundPassthrough is called whenever a new passthrough filter chain is added to the LDS output.
    // Can be used to add additional filters.
    OnInboundPassthrough(in *InputParams, mutable *istionetworking.MutableObjects) error

    // OnInboundPassthroughFilterChains is called whenever a plugin needs to setup custom pass through filter chain.
    OnInboundPassthroughFilterChains(in *InputParams) []istionetworking.FilterChain
}