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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package autocert
import (
"context"
"crypto"
"sync"
"time"
)
// renewJitter is the maximum deviation from Manager.RenewBefore.
const renewJitter = time.Hour
// domainRenewal tracks the state used by the periodic timers
// renewing a single domain's cert.
type domainRenewal struct {
m *Manager
ck certKey
key crypto.Signer
timerMu sync.Mutex
timer *time.Timer
}
// start starts a cert renewal timer at the time
// defined by the certificate expiration time exp.
//
// If the timer is already started, calling start is a noop.
func (dr *domainRenewal) start(exp time.Time) {
dr.timerMu.Lock()
defer dr.timerMu.Unlock()
if dr.timer != nil {
return
}
dr.timer = time.AfterFunc(dr.next(exp), dr.renew)
}
// stop stops the cert renewal timer.
// If the timer is already stopped, calling stop is a noop.
func (dr *domainRenewal) stop() {
dr.timerMu.Lock()
defer dr.timerMu.Unlock()
if dr.timer == nil {
return
}
dr.timer.Stop()
dr.timer = nil
}
// renew is called periodically by a timer.
// The first renew call is kicked off by dr.start.
func (dr *domainRenewal) renew() {
dr.timerMu.Lock()
defer dr.timerMu.Unlock()
if dr.timer == nil {
return
}
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
defer cancel()
// TODO: rotate dr.key at some point?
next, err := dr.do(ctx)
if err != nil {
next = renewJitter / 2
next += time.Duration(pseudoRand.int63n(int64(next)))
}
dr.timer = time.AfterFunc(next, dr.renew)
testDidRenewLoop(next, err)
}
// updateState locks and replaces the relevant Manager.state item with the given
// state. It additionally updates dr.key with the given state's key.
func (dr *domainRenewal) updateState(state *certState) {
dr.m.stateMu.Lock()
defer dr.m.stateMu.Unlock()
dr.key = state.key
dr.m.state[dr.ck] = state
}
// do is similar to Manager.createCert but it doesn't lock a Manager.state item.
// Instead, it requests a new certificate independently and, upon success,
// replaces dr.m.state item with a new one and updates cache for the given domain.
//
// It may lock and update the Manager.state if the expiration date of the currently
// cached cert is far enough in the future.
//
// The returned value is a time interval after which the renewal should occur again.
func (dr *domainRenewal) do(ctx context.Context) (time.Duration, error) {
// a race is likely unavoidable in a distributed environment
// but we try nonetheless
if tlscert, err := dr.m.cacheGet(ctx, dr.ck); err == nil {
next := dr.next(tlscert.Leaf.NotAfter)
if next > dr.m.renewBefore()+renewJitter {
signer, ok := tlscert.PrivateKey.(crypto.Signer)
if ok {
state := &certState{
key: signer,
cert: tlscert.Certificate,
leaf: tlscert.Leaf,
}
dr.updateState(state)
return next, nil
}
}
}
der, leaf, err := dr.m.authorizedCert(ctx, dr.key, dr.ck)
if err != nil {
return 0, err
}
state := &certState{
key: dr.key,
cert: der,
leaf: leaf,
}
tlscert, err := state.tlscert()
if err != nil {
return 0, err
}
if err := dr.m.cachePut(ctx, dr.ck, tlscert); err != nil {
return 0, err
}
dr.updateState(state)
return dr.next(leaf.NotAfter), nil
}
func (dr *domainRenewal) next(expiry time.Time) time.Duration {
d := expiry.Sub(dr.m.now()) - dr.m.renewBefore()
// add a bit of randomness to renew deadline
n := pseudoRand.int63n(int64(renewJitter))
d -= time.Duration(n)
if d < 0 {
return 0
}
return d
}
var testDidRenewLoop = func(next time.Duration, err error) {}