micro/network/router/query.go

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package router
// LookupPolicy defines query policy
type LookupPolicy int
const (
// DiscardNoRoute discards query when no route is found
DiscardNoRoute LookupPolicy = iota
// ClosestMatch returns closest match to supplied query
ClosestMatch
)
// String returns human representation of LookupPolicy
func (lp LookupPolicy) String() string {
switch lp {
case DiscardNoRoute:
return "DISCARD"
case ClosestMatch:
return "CLOSEST"
default:
return "UNKNOWN"
}
}
// QueryOption sets routing table query options
type QueryOption func(*QueryOptions)
// QueryOptions are routing table query options
type QueryOptions struct {
// Destination is destination address
Destination string
// Network is network address
Network string
// Router is gateway address
Router Router
// Metric is route metric
Metric int
// Policy is query lookup policy
Policy LookupPolicy
}
// QueryDestination sets query destination address
func QueryDestination(a string) QueryOption {
return func(o *QueryOptions) {
o.Destination = a
}
}
// QueryNetwork sets query network address
func QueryNetwork(a string) QueryOption {
return func(o *QueryOptions) {
o.Network = a
}
}
// QueryRouter sets query gateway address
func QueryRouter(r Router) QueryOption {
return func(o *QueryOptions) {
o.Router = r
}
}
// QueryMetric sets query metric
func QueryMetric(m int) QueryOption {
return func(o *QueryOptions) {
o.Metric = m
}
}
// QueryPolicy sets query policy
// NOTE: this might be renamed to filter or some such
func QueryPolicy(p LookupPolicy) QueryOption {
return func(o *QueryOptions) {
o.Policy = p
}
}
// Query is routing table query
type Query interface {
// Options returns query options
Options() QueryOptions
}
// query is a basic implementation of Query
type query struct {
opts QueryOptions
}
// NewQuery creates new query and returns it
func NewQuery(opts ...QueryOption) Query {
// default gateway for wildcard router
r := newRouter(ID("*"))
// default options
// NOTE: by default we use DefaultNetworkMetric
qopts := QueryOptions{
Destination: "*",
Network: "*",
Router: r,
Metric: DefaultNetworkMetric,
Policy: DiscardNoRoute,
}
for _, o := range opts {
o(&qopts)
}
return &query{
opts: qopts,
}
}
// Options returns query options
func (q *query) Options() QueryOptions {
return q.opts
}