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: "*", 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() }