micro/network/router/table/query.go

134 lines
2.6 KiB
Go

package table
import (
"fmt"
"strings"
"github.com/olekukonko/tablewriter"
)
// LookupPolicy defines query policy
type LookupPolicy int
const (
// DiscardIfNone discards query when no route is found
DiscardIfNone LookupPolicy = iota
// ClosestMatch returns closest match to supplied query
ClosestMatch
)
// String returns human representation of LookupPolicy
func (lp LookupPolicy) String() string {
switch lp {
case DiscardIfNone:
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 router address
Router string
// Policy is query lookup policy
Policy LookupPolicy
}
// QueryDestination sets destination address
func QueryDestination(d string) QueryOption {
return func(o *QueryOptions) {
o.Destination = d
}
}
// QueryNetwork sets route network address
func QueryNetwork(a string) QueryOption {
return func(o *QueryOptions) {
o.Network = a
}
}
// QueryRouter sets route router address
func QueryRouter(r string) QueryOption {
return func(o *QueryOptions) {
o.Router = r
}
}
// 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 options
// NOTE: by default we use DefaultNetworkMetric
qopts := QueryOptions{
Destination: "*",
Router: "*",
Network: "*",
Policy: DiscardIfNone,
}
for _, o := range opts {
o(&qopts)
}
return &query{
opts: qopts,
}
}
// Options returns query options
func (q *query) Options() QueryOptions {
return q.opts
}
// String prints routing table query in human readable form
func (q query) String() string {
// this will help us build routing table string
sb := &strings.Builder{}
// create nice table printing structure
table := tablewriter.NewWriter(sb)
table.SetHeader([]string{"Destination", "Network", "Router", "Policy"})
strQuery := []string{
q.opts.Destination,
q.opts.Network,
q.opts.Router,
fmt.Sprintf("%s", q.opts.Policy),
}
table.Append(strQuery)
// render table into sb
table.Render()
return sb.String()
}