caddyauth: Use singleflight for basic auth (#5344)

* caddyauth: Add singleflight for basic auth

* Fixes #5338
* it occurred the thunder herd problem like this https://medium.com/@mhrlife/avoid-duplicate-requests-while-filling-cache-98c687879f59

* Update modules/caddyhttp/caddyauth/basicauth.go

Fix comment

Co-authored-by: Francis Lavoie <lavofr@gmail.com>

---------

Co-authored-by: Francis Lavoie <lavofr@gmail.com>
Co-authored-by: Matt Holt <mholt@users.noreply.github.com>
This commit is contained in:
Y.Horie 2023-02-07 03:29:03 +09:00 committed by GitHub
parent ac83b7e218
commit 8d3a1b8bcb
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2 changed files with 12 additions and 2 deletions

1
go.mod
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@ -32,6 +32,7 @@ require (
go.uber.org/zap v1.23.0
golang.org/x/crypto v0.4.0
golang.org/x/net v0.5.0
golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4
golang.org/x/term v0.4.0
google.golang.org/genproto v0.0.0-20221027153422-115e99e71e1c
gopkg.in/natefinch/lumberjack.v2 v2.0.0

View File

@ -26,6 +26,7 @@ import (
"time"
"github.com/caddyserver/caddy/v2"
"golang.org/x/sync/singleflight"
)
func init() {
@ -142,6 +143,7 @@ func (hba *HTTPBasicAuth) Provision(ctx caddy.Context) error {
if hba.HashCache != nil {
hba.HashCache.cache = make(map[string]bool)
hba.HashCache.mu = new(sync.RWMutex)
hba.HashCache.g = new(singleflight.Group)
}
return nil
@ -190,12 +192,18 @@ func (hba HTTPBasicAuth) correctPassword(account Account, plaintextPassword []by
if ok {
return same, nil
}
// slow track: do the expensive op, then add it to the cache
same, err := compare()
// but perform it in a singleflight group so that multiple
// parallel requests using the same password don't cause a
// thundering herd problem by all performing the same hashing
// operation before the first one finishes and caches it.
v, err, _ := hba.HashCache.g.Do(cacheKey, func() (any, error) {
return compare()
})
if err != nil {
return false, err
}
same = v.(bool)
hba.HashCache.mu.Lock()
if len(hba.HashCache.cache) >= 1000 {
hba.HashCache.makeRoom() // keep cache size under control
@ -223,6 +231,7 @@ func (hba HTTPBasicAuth) promptForCredentials(w http.ResponseWriter, err error)
// compute on every HTTP request.
type Cache struct {
mu *sync.RWMutex
g *singleflight.Group
// map of concatenated hashed password + plaintext password + salt, to result
cache map[string]bool