hugo/common/tasks/tasks.go
2024-06-04 16:07:39 +02:00

153 lines
3.1 KiB
Go

// Copyright 2024 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package tasks
import (
"sync"
"time"
)
// RunEvery runs a function at intervals defined by the function itself.
// Functions can be added and removed while running.
type RunEvery struct {
// Any error returned from the function will be passed to this function.
HandleError func(string, error)
// If set, the function will be run immediately.
RunImmediately bool
// The named functions to run.
funcs map[string]*Func
mu sync.Mutex
started bool
closed bool
quit chan struct{}
}
type Func struct {
// The shortest interval between each run.
IntervalLow time.Duration
// The longest interval between each run.
IntervalHigh time.Duration
// The function to run.
F func(interval time.Duration) (time.Duration, error)
interval time.Duration
last time.Time
}
func (r *RunEvery) Start() error {
if r.started {
return nil
}
r.started = true
r.quit = make(chan struct{})
go func() {
if r.RunImmediately {
r.run()
}
ticker := time.NewTicker(500 * time.Millisecond)
defer ticker.Stop()
for {
select {
case <-r.quit:
return
case <-ticker.C:
r.run()
}
}
}()
return nil
}
// Close stops the RunEvery from running.
func (r *RunEvery) Close() error {
if r.closed {
return nil
}
r.closed = true
if r.quit != nil {
close(r.quit)
}
return nil
}
// Add adds a function to the RunEvery.
func (r *RunEvery) Add(name string, f Func) {
r.mu.Lock()
defer r.mu.Unlock()
if r.funcs == nil {
r.funcs = make(map[string]*Func)
}
if f.IntervalLow == 0 {
f.IntervalLow = 500 * time.Millisecond
}
if f.IntervalHigh <= f.IntervalLow {
f.IntervalHigh = 20 * time.Second
}
start := f.IntervalHigh / 3
if start < f.IntervalLow {
start = f.IntervalLow
}
f.interval = start
f.last = time.Now()
r.funcs[name] = &f
}
// Remove removes a function from the RunEvery.
func (r *RunEvery) Remove(name string) {
r.mu.Lock()
defer r.mu.Unlock()
delete(r.funcs, name)
}
// Has returns whether the RunEvery has a function with the given name.
func (r *RunEvery) Has(name string) bool {
r.mu.Lock()
defer r.mu.Unlock()
_, found := r.funcs[name]
return found
}
func (r *RunEvery) run() {
r.mu.Lock()
defer r.mu.Unlock()
for name, f := range r.funcs {
if time.Now().Before(f.last.Add(f.interval)) {
continue
}
f.last = time.Now()
interval, err := f.F(f.interval)
if err != nil && r.HandleError != nil {
r.HandleError(name, err)
}
if interval < f.IntervalLow {
interval = f.IntervalLow
}
if interval > f.IntervalHigh {
interval = f.IntervalHigh
}
f.interval = interval
}
}