/
keyset.go
101 lines (88 loc) · 2.52 KB
/
keyset.go
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package google
import (
"context"
"crypto/x509"
"fmt"
"time"
"github.com/jbrekelmans/go-lib/auth"
"github.com/jbrekelmans/go-lib/cache"
)
const (
// DefaultCachingKeySetProviderTimeToLive is a common default for the timeToLive parameter of CachingKeySetProvider.
DefaultCachingKeySetProviderTimeToLive = time.Minute * 5
)
// KeySet contains entries where each entry represents a key identifier and certificate.
type KeySet = map[string]*x509.Certificate
// KeySetProvider is an interface for getting a set of keys.
type KeySetProvider interface {
// The returned map should not be modified.
Get(ctx context.Context) (KeySet, error)
}
type staticKeySetProvider struct {
keySet KeySet
}
// StaticKeySetProvider is an in-memory KeySetProvider.
// The values of the keySet parameter should be PEM encoded X509 certificates.
func StaticKeySetProvider(keySet map[string]string) (KeySetProvider, error) {
s := &staticKeySetProvider{
keySet: KeySet{},
}
for keyID, certificatePEM := range keySet {
certificate, err := auth.ParseCertificate(certificatePEM)
if err != nil {
return nil, fmt.Errorf("keySet[%#v] is invalid: %w", keyID, err)
}
s.keySet[keyID] = certificate
}
return s, nil
}
// Get implements KeySetProvider.
func (s *staticKeySetProvider) Get(ctx context.Context) (KeySet, error) {
return s.keySet, nil
}
type cachingKeySetProvider struct {
base KeySetProvider
cachedEvaluator cache.CachedEvaluator
timeToLive time.Duration
}
type keySetWithExpires struct {
keySet KeySet
expires time.Time
}
// CachingKeySetProvider wrapss a KeySetProvider and adds caching.
func CachingKeySetProvider(timeToLive time.Duration, base KeySetProvider) KeySetProvider {
c := &cachingKeySetProvider{
base: base,
timeToLive: timeToLive,
}
c.cachedEvaluator, _ = cache.NewCachedEvaluator(c.evaluator)
return c
}
func (c *cachingKeySetProvider) evaluator(ctx context.Context) (value interface{}, err error) {
keySet, err := c.base.Get(ctx)
if keySet != nil {
value = &keySetWithExpires{
keySet: keySet,
expires: time.Now().Add(c.timeToLive),
}
}
return
}
// Get implements KeySetProvider.
func (c *cachingKeySetProvider) Get(ctx context.Context) (KeySet, error) {
value := c.cachedEvaluator.GetCacheOnly()
if value != nil {
valueT := value.(*keySetWithExpires)
if !time.Now().Before(valueT.expires) {
value = nil
}
}
if value == nil {
var err error
value, err = c.cachedEvaluator.Evaluate(ctx)
if err != nil {
return nil, err
}
}
return value.(*keySetWithExpires).keySet, nil
}