103 lines
2.1 KiB
Go
103 lines
2.1 KiB
Go
package lntest
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import (
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"context"
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"encoding/json"
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"fmt"
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"io"
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"net/http"
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"sync"
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"github.com/lightningnetwork/lnd/lnwallet/chainfee"
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)
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const (
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// feeServiceTarget is the confirmation target for which a fee estimate
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// is returned. Requests for higher confirmation targets will fall back
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// to this.
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feeServiceTarget = 2
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)
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// feeService runs a web service that provides fee estimation information.
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type feeService struct {
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feeEstimates
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srv *http.Server
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wg sync.WaitGroup
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url string
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lock sync.Mutex
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}
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// feeEstimates contains the current fee estimates.
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type feeEstimates struct {
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Fees map[uint32]uint32 `json:"fee_by_block_target"`
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}
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// startFeeService spins up a go-routine to serve fee estimates.
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func startFeeService() *feeService {
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port := NextAvailablePort()
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f := feeService{
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url: fmt.Sprintf("http://localhost:%v/fee-estimates.json", port),
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}
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// Initialize default fee estimate.
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f.Fees = map[uint32]uint32{feeServiceTarget: 50000}
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listenAddr := fmt.Sprintf(":%v", port)
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f.srv = &http.Server{
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Addr: listenAddr,
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}
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http.HandleFunc("/fee-estimates.json", f.handleRequest)
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f.wg.Add(1)
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go func() {
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defer f.wg.Done()
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if err := f.srv.ListenAndServe(); err != http.ErrServerClosed {
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fmt.Printf("error: cannot start fee api: %v", err)
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}
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}()
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return &f
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}
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// handleRequest handles a client request for fee estimates.
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func (f *feeService) handleRequest(w http.ResponseWriter, r *http.Request) {
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f.lock.Lock()
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defer f.lock.Unlock()
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bytes, err := json.Marshal(f.feeEstimates)
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if err != nil {
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fmt.Printf("error: cannot serialize "+
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"estimates: %v", err)
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return
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}
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_, err = io.WriteString(w, string(bytes))
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if err != nil {
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fmt.Printf("error: cannot send estimates: %v",
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err)
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}
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}
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// stop stops the web server.
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func (f *feeService) stop() {
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if err := f.srv.Shutdown(context.Background()); err != nil {
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fmt.Printf("error: cannot stop fee api: %v", err)
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}
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f.wg.Wait()
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}
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// setFee changes the current fee estimate for the fixed confirmation target.
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func (f *feeService) setFee(fee chainfee.SatPerKWeight) {
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f.lock.Lock()
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defer f.lock.Unlock()
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f.Fees[feeServiceTarget] = uint32(fee.FeePerKVByte())
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}
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