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|
package leaf
import (
"bytes"
"context"
"crypto/rand"
"encoding/binary"
"fmt"
"net/http"
"time"
"git.sigsum.org/sigsum-go/pkg/merkle"
"git.sigsum.org/sigsum-go/pkg/requests"
"git.sigsum.org/sigsum-go/pkg/types"
)
type worker struct {
Config
inCh chan *event // events that received 202
outCh chan *event // events that received status 2XX
}
type event struct {
start time.Time // time that request started
end time.Time // time that request ended with 2XX
req *http.Request // prepared add-leaf request
got200 bool // true if 200 response
got202 bool // true if at least one 202 responses
num3xx uint64 // number of encountered 3xx before 2XX
num4xx uint64 // number of encountered 4xx before 2XX
num5xx uint64 // number of encountered 5xx before 2XX
}
func (w *worker) submit(ctx context.Context) error {
data := make([]byte, 40)
if _, err := rand.Read(data); err != nil {
return fmt.Errorf("generate data: %v", err)
}
ctr := uint64(0)
for {
ctr += 1
binary.BigEndian.PutUint64(data[:8], ctr)
req, err := w.newRequest(merkle.HashFn(data))
if err != nil {
return err
}
ev := event{req: req, start: time.Now()}
for {
select {
case <-ctx.Done():
return nil
case <-time.After(w.Wait):
}
if err := w.doRequest(&ev); err == nil {
break // success
}
}
select {
case w.outCh <- &ev:
default:
return fmt.Errorf("out channel is full")
}
}
}
func (w *worker) check(ctx context.Context) error {
// setup a backoff mechanism that doesn't block
next := make(chan struct{}, 1)
backoff := func() {
time.Sleep(w.backoff)
next <- struct{}{}
}
next <- struct{}{}
defer func() {
<-next // empty channel before closing
defer close(next)
}()
evs := make([]*event, 0, w.maxEvents)
for {
if len(evs) == w.maxEvents {
return fmt.Errorf("checker has too many queued events: %d", w.maxEvents)
}
select {
case <-ctx.Done():
return nil
case ev := <-w.inCh:
evs = append(evs, ev)
continue
case <-next:
if len(evs) == 0 {
go backoff()
continue
}
}
if err := w.doRequest(evs[0]); err != nil {
go backoff()
continue
}
next <- struct{}{} // no backoff after success
select {
case w.outCh <- evs[0]:
default:
return fmt.Errorf("out channel is full")
}
evs = evs[1:]
}
}
func (w *worker) newRequest(msg *merkle.Hash) (*http.Request, error) {
stm := types.Statement{
ShardHint: uint64(time.Now().Unix()),
Checksum: *merkle.HashFn(msg[:]),
}
sig, err := stm.Sign(w.signer)
if err != nil {
return nil, err
}
leaf := requests.Leaf{
ShardHint: stm.ShardHint,
Message: *msg,
Signature: *sig,
PublicKey: w.pub,
DomainHint: w.DomainHint,
}
buf := bytes.NewBuffer(nil)
if err := leaf.ToASCII(buf); err != nil {
return nil, fmt.Errorf("serialize leaf request: %v", err)
}
req, err := http.NewRequest(http.MethodPost, w.url, buf)
if err != nil {
return nil, fmt.Errorf("create http request: %v", err)
}
return req, nil
}
func (w *worker) doRequest(ev *event) error {
rsp, err := w.cli.Do(ev.req)
if err != nil {
return err
}
defer rsp.Body.Close()
if rsp.StatusCode == http.StatusOK {
ev.got200 = true
ev.end = time.Now()
return nil
} else if rsp.StatusCode == http.StatusAccepted {
if !ev.got202 {
ev.got202 = true
ev.end = time.Now()
return nil // first 202 response
}
} else if rsp.StatusCode >= 300 && rsp.StatusCode < 400 {
ev.num3xx += 1
} else if rsp.StatusCode >= 400 && rsp.StatusCode < 500 {
ev.num4xx += 1
} else if rsp.StatusCode >= 500 && rsp.StatusCode < 600 {
ev.num5xx += 1
}
return fmt.Errorf("status %d", err)
}
func (ev *event) resetCounters() {
ev.num3xx = 0
ev.num4xx = 0
ev.num5xx = 0
}
|
