feat(auth): accept clock skew for token validation

internal/auth/agent/authenticator.go

@@ -14,8 +14,11 @@ import (
 	"gitlab.com/wpetit/goweb/logger"
 )
 
+const DefaultAcceptableSkew = 5 * time.Minute
+
 type Authenticator struct {
-	repo datastore.AgentRepository
+	repo           datastore.AgentRepository
+	acceptableSkew time.Duration
 }
 
 // Authenticate implements auth.Authenticator.
@@ -72,6 +75,7 @@ func (a *Authenticator) Authenticate(ctx context.Context, r *http.Request) (auth
 		[]byte(rawToken),
 		jwt.WithKeySet(agent.KeySet.Set, jws.WithRequireKid(false)),
 		jwt.WithValidate(true),
+		jwt.WithAcceptableSkew(a.acceptableSkew),
 	)
 	if err != nil {
 		return nil, errors.WithStack(err)
@@ -91,9 +95,10 @@ func (a *Authenticator) Authenticate(ctx context.Context, r *http.Request) (auth
 	return user, nil
 }
 
-func NewAuthenticator(repo datastore.AgentRepository) *Authenticator {
+func NewAuthenticator(repo datastore.AgentRepository, acceptableSkew time.Duration) *Authenticator {
 	return &Authenticator{
-		repo: repo,
+		repo:           repo,
+		acceptableSkew: acceptableSkew,
 	}
 }