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Merge branch 'infrastructure'

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* infrastructure:
  chore(stdiscosrv): smooth retry-after delays over a slightly larger normal distribution
  chore(stdiscosrv): optionally delay shutdown
  chore(stdiscosrv): adjust desired seen and unseen rate separately
This commit is contained in:
Jakob Borg
2026-04-07 17:22:35 +02:00
parent 6a26d56ad9 3ac9b83f40
commit f806967958
3 changed files with 78 additions and 14 deletions
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20
cmd/stdiscosrv/apisrv.go
View File

@@ -67,7 +67,7 @@ type contextKey int
const idKey contextKey = iota
func newAPISrv(addr string, cert tls.Certificate, db database, repl replicator, useHTTP, compression bool, desiredNotFoundRate float64) *apiSrv {
func newAPISrv(addr string, cert tls.Certificate, db database, repl replicator, useHTTP, compression bool, desiredUnseenNotFoundRate, desiredSeenNotFoundRate float64) *apiSrv {
return &apiSrv{
addr: addr,
cert: cert,
@@ -78,13 +78,13 @@ func newAPISrv(addr string, cert tls.Certificate, db database, repl replicator,
seenTracker: &retryAfterTracker{
name: "seenTracker",
bucketStarts: time.Now(),
desiredRate: desiredNotFoundRate / 2,
desiredRate: desiredSeenNotFoundRate,
currentDelay: notFoundRetryUnknownMinSeconds,
},
notSeenTracker: &retryAfterTracker{
name: "notSeenTracker",
bucketStarts: time.Now(),
desiredRate: desiredNotFoundRate / 2,
desiredRate: desiredUnseenNotFoundRate,
currentDelay: notFoundRetryUnknownMaxSeconds / 2,
},
}
@@ -564,5 +564,17 @@ func (t *retryAfterTracker) retryAfterS() int {
}
t.curCount++
t.mut.Unlock()
return t.currentDelay + rand.Intn(t.currentDelay/4)
// Skewed normal distribution with the mean at currentDelay and the
// limits (50% and 150%) at 3 standard deviations
nf := rand.NormFloat64()
minD := max(notFoundRetryUnknownMinSeconds, t.currentDelay/2)
maxD := min(notFoundRetryUnknownMaxSeconds, t.currentDelay*3/2)
intv := float64(maxD - t.currentDelay)
if nf < 0 {
intv = float64(t.currentDelay - minD)
}
nf = min(max(nf*intv/3+float64(t.currentDelay), notFoundRetryUnknownMinSeconds), notFoundRetryUnknownMaxSeconds)
return int(nf)
}

50
cmd/stdiscosrv/apisrv_test.go
View File

@@ -18,6 +18,7 @@ import (
"regexp"
"strings"
"testing"
"time"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/tlsutil"
@@ -106,12 +107,59 @@ func addr(host string, port int) *net.TCPAddr {
}
}
func TestRetryAfterSHistogram(t *testing.T) {
tracker := &retryAfterTracker{
name: "test",
bucketStarts: time.Now(),
desiredRate: 100,
currentDelay: 1800,
}
const n = 1000
bucketSize := 60 // seconds per histogram bucket
numBuckets := (notFoundRetryUnknownMaxSeconds + bucketSize - 1) / bucketSize
buckets := make([]int, numBuckets)
for i := 0; i < n; i++ {
v := tracker.retryAfterS()
if v < notFoundRetryUnknownMinSeconds || v > notFoundRetryUnknownMaxSeconds {
t.Fatalf("retryAfterS() = %d, out of range [%d, %d]", v, notFoundRetryUnknownMinSeconds, notFoundRetryUnknownMaxSeconds)
}
b := (v - 1) / bucketSize
if b >= numBuckets {
b = numBuckets - 1
}
buckets[b]++
}
// Print a horizontal histogram
maxCount := 0
for _, c := range buckets {
if c > maxCount {
maxCount = c
}
}
barWidth := 60
for i, c := range buckets {
lo := i*bucketSize + 1
hi := (i + 1) * bucketSize
if hi > notFoundRetryUnknownMaxSeconds {
hi = notFoundRetryUnknownMaxSeconds
}
bar := ""
if maxCount > 0 {
bar = strings.Repeat("#", c*barWidth/maxCount)
}
t.Logf("%4d-%4ds | %-*s %d", lo, hi, barWidth, bar, c)
}
}
func BenchmarkAPIRequests(b *testing.B) {
db := newInMemoryStore(b.TempDir(), 0, nil)
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
go db.Serve(ctx)
api := newAPISrv("127.0.0.1:0", tls.Certificate{}, db, nil, true, true, 1000)
api := newAPISrv("127.0.0.1:0", tls.Certificate{}, db, nil, true, true, 1000, 1000)
srv := httptest.NewServer(http.HandlerFunc(api.handler))
kf := b.TempDir() + "/cert"

22
cmd/stdiscosrv/main.go
View File

@@ -57,13 +57,16 @@ const (
var debug = false
type CLI struct {
Cert string `group:"Listen" help:"Certificate file" default:"./cert.pem" env:"DISCOVERY_CERT_FILE"`
Key string `group:"Listen" help:"Key file" default:"./key.pem" env:"DISCOVERY_KEY_FILE"`
HTTP bool `group:"Listen" help:"Listen on HTTP (behind an HTTPS proxy)" env:"DISCOVERY_HTTP"`
Compression bool `group:"Listen" help:"Enable GZIP compression of responses" env:"DISCOVERY_COMPRESSION"`
Listen string `group:"Listen" help:"Listen address" default:":8443" env:"DISCOVERY_LISTEN"`
MetricsListen string `group:"Listen" help:"Metrics listen address" env:"DISCOVERY_METRICS_LISTEN"`
DesiredNotFoundRate float64 `group:"Listen" help:"Desired maximum rate of not-found replies (/s)" default:"1000"`
Cert string `group:"Listen" help:"Certificate file" default:"./cert.pem" env:"DISCOVERY_CERT_FILE"`
Key string `group:"Listen" help:"Key file" default:"./key.pem" env:"DISCOVERY_KEY_FILE"`
HTTP bool `group:"Listen" help:"Listen on HTTP (behind an HTTPS proxy)" env:"DISCOVERY_HTTP"`
Compression bool `group:"Listen" help:"Enable GZIP compression of responses" env:"DISCOVERY_COMPRESSION"`
Listen string `group:"Listen" help:"Listen address" default:":8443" env:"DISCOVERY_LISTEN"`
MetricsListen string `group:"Listen" help:"Metrics listen address" env:"DISCOVERY_METRICS_LISTEN"`
DesiredUnseenNotFoundRate float64 `group:"Listen" help:"Desired maximum rate of not-found replies for never seen devices (/s)" default:"1000" env:"DISCOVERY_UNSEEN_RATE"`
DesiredSeenNotFoundRate float64 `group:"Listen" help:"Desired maximum rate of not-found replies for previously seen devices (/s)" default:"1000" env:"DISCOVERY_SEEN_RATE"`
ShutdownDelay float64 `help:"Time to wait before shutdown after receiving a shutdown signal (s)" env:"DISCOVERY_SHUTDOWN_DELAY"`
DBDir string `group:"Database" help:"Database directory" default:"." env:"DISCOVERY_DB_DIR"`
DBFlushInterval time.Duration `group:"Database" help:"Interval between database flushes" default:"5m" env:"DISCOVERY_DB_FLUSH_INTERVAL"`
@@ -145,7 +148,7 @@ func main() {
}
// Start the main API server.
qs := newAPISrv(cli.Listen, cert, db, repl, cli.HTTP, cli.Compression, cli.DesiredNotFoundRate)
qs := newAPISrv(cli.Listen, cert, db, repl, cli.HTTP, cli.Compression, cli.DesiredUnseenNotFoundRate, cli.DesiredSeenNotFoundRate)
main.Add(qs)
// If we have a metrics port configured, start a metrics handler.
@@ -167,7 +170,8 @@ func main() {
signal.Notify(signalChan, os.Interrupt)
go func() {
sig := <-signalChan
slog.Info("Received signal; shutting down", "signal", sig)
slog.Info("Received signal; shutting down", "signal", sig, "delay", cli.ShutdownDelay)
time.Sleep(time.Duration(float64(time.Second) * cli.ShutdownDelay))
cancel()
}()