rclone/fs/pacer.go

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// Pacer with logging and calculator
package fs
import (
"context"
"time"
"github.com/rclone/rclone/fs/fserrors"
"github.com/rclone/rclone/lib/pacer"
)
// Pacer is a simple wrapper around a pacer.Pacer with logging.
type Pacer struct {
*pacer.Pacer
}
type logCalculator struct {
pacer.Calculator
}
// NewPacer creates a Pacer for the given Fs and Calculator.
func NewPacer(ctx context.Context, c pacer.Calculator) *Pacer {
ci := GetConfig(ctx)
retries := ci.LowLevelRetries
if retries <= 0 {
retries = 1
}
p := &Pacer{
Pacer: pacer.New(
pacer.InvokerOption(pacerInvoker),
// pacer.MaxConnectionsOption(ci.Checkers+ci.Transfers),
pacer.RetriesOption(retries),
pacer.CalculatorOption(c),
),
}
p.SetCalculator(c)
return p
}
func (d *logCalculator) Calculate(state pacer.State) time.Duration {
oldSleepTime := state.SleepTime
newSleepTime := d.Calculator.Calculate(state)
if state.ConsecutiveRetries > 0 {
if newSleepTime != oldSleepTime {
Debugf("pacer", "Rate limited, increasing sleep to %v", newSleepTime)
}
} else {
if newSleepTime != oldSleepTime {
Debugf("pacer", "Reducing sleep to %v", newSleepTime)
}
}
return newSleepTime
}
// SetCalculator sets the pacing algorithm. Don't modify the Calculator object
// afterwards, use the ModifyCalculator method when needed.
//
// It will choose the default algorithm if nil is passed in.
func (p *Pacer) SetCalculator(c pacer.Calculator) {
switch c.(type) {
case *logCalculator:
Logf("pacer", "Invalid Calculator in fs.Pacer.SetCalculator")
case nil:
c = &logCalculator{pacer.NewDefault()}
default:
c = &logCalculator{c}
}
p.Pacer.SetCalculator(c)
}
// ModifyCalculator calls the given function with the currently configured
// Calculator and the Pacer lock held.
func (p *Pacer) ModifyCalculator(f func(pacer.Calculator)) {
p.Pacer.ModifyCalculator(func(c pacer.Calculator) {
switch _c := c.(type) {
case *logCalculator:
f(_c.Calculator)
default:
Logf("pacer", "Invalid Calculator in fs.Pacer: %t", c)
f(c)
}
})
}
func pacerInvoker(try, retries int, f pacer.Paced) (retry bool, err error) {
retry, err = f()
if retry {
Debugf("pacer", "low level retry %d/%d (error %v)", try, retries, err)
err = fserrors.RetryError(err)
}
return
}