m/pkg/event: make type-safe
This is a fairly large change which makes use of Go type parameters
(“generics”) to make the event library (and its memory/etcd
implementations) type safe.
Since we now have the event.Value interface strongly typed, we also move
options which were implementation-specific (like BacklogOnly)
to be part of that interface, instead of the previously type-asserted
specific implementations. Use of options that are not handled by a
particular implementation is a runtime error. Expressing this in the
type system is probably not worth the effort.
We also implement Filter to allow offloading some of the functionality previously implemented in type assertion wrappers into the library itself.
In the end, this ends up removing a bunch of type assertion code, at
the cost of a fairly sweeping change. Unfortunately, some of this is due
to IntelliJ suddenly deciding to reformat comments.
Change-Id: I1ca6d93db1b5c4055a21af3fb9e5e3d425c0d86e
Reviewed-on: https://review.monogon.dev/c/monogon/+/1322
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/metropolis/pkg/pki/crl.go b/metropolis/pkg/pki/crl.go
index 8b886bf..23838a1 100644
--- a/metropolis/pkg/pki/crl.go
+++ b/metropolis/pkg/pki/crl.go
@@ -145,8 +145,8 @@
// WatchCRL returns and Event Value compatible CRLWatcher which can be used to
// retrieve and watch for the newest CRL available from this CA certificate.
-func (c *Certificate) WatchCRL(cl client.Namespaced) CRLWatcher {
- value := etcd.NewValue(cl, c.crlPath(), func(_, data []byte) (interface{}, error) {
+func (c *Certificate) WatchCRL(cl client.Namespaced) event.Watcher[*CRL] {
+ value := etcd.NewValue(cl, c.crlPath(), func(_, data []byte) (*CRL, error) {
crl, err := x509.ParseCRL(data)
if err != nil {
return nil, fmt.Errorf("could not parse CRL from etcd: %w", err)
@@ -156,29 +156,10 @@
List: crl,
}, nil
})
- return CRLWatcher{value.Watch()}
-}
-
-// CRLWatcher is a Event Value compatible Watcher which will be updated any time
-// a given CA certificate's CRL gets updated.
-type CRLWatcher struct {
- event.Watcher
+ return value.Watch()
}
type CRL struct {
Raw []byte
List *pkix.CertificateList
}
-
-// Retrieve the newest available CRL from etcd, blocking until one is available
-// or updated.
-//
-// The first call will block until a CRL is available, which happens the first
-// time a given CA certificate is stored in etcd (eg. through an Ensure call).
-func (c *CRLWatcher) Get(ctx context.Context, opts ...event.GetOption) (*CRL, error) {
- v, err := c.Watcher.Get(ctx, opts...)
- if err != nil {
- return nil, err
- }
- return v.(*CRL), nil
-}