Plugins: Add validation stage to plugin loader pipeline (#73053)

* first pass

* change validation signature

* err tracking

* fix

* undo golden

* 1 more

* fix

* adjust doc

* add test helper

* fix linter

pkg/services/pluginsintegration/pluginerrs/errors.go

@@ -0,0 +1,71 @@
+package pluginerrs
+
+import (
+	"context"
+
+	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/plugins/log"
+)
+
+var _ plugins.ErrorResolver = (*Store)(nil)
+
+type Store struct {
+	signatureErrs SignatureErrorTracker
+}
+
+func ProvideStore(signatureErrs SignatureErrorTracker) *Store {
+	return &Store{
+		signatureErrs: signatureErrs,
+	}
+}
+
+func (s *Store) PluginErrors() []*plugins.Error {
+	sigErrs := s.signatureErrs.SignatureErrors(context.Background())
+	errs := make([]*plugins.Error, 0, len(sigErrs))
+	for _, err := range sigErrs {
+		errs = append(errs, &plugins.Error{
+			PluginID:  err.PluginID,
+			ErrorCode: err.AsErrorCode(),
+		})
+	}
+
+	return errs
+}
+
+type SignatureErrorRegistry struct {
+	errs map[string]*plugins.SignatureError
+	log  log.Logger
+}
+
+type SignatureErrorTracker interface {
+	Record(ctx context.Context, err *plugins.SignatureError)
+	Clear(ctx context.Context, pluginID string)
+	SignatureErrors(ctx context.Context) []*plugins.SignatureError
+}
+
+func ProvideSignatureErrorTracker() *SignatureErrorRegistry {
+	return newSignatureErrorRegistry()
+}
+
+func newSignatureErrorRegistry() *SignatureErrorRegistry {
+	return &SignatureErrorRegistry{
+		errs: make(map[string]*plugins.SignatureError),
+		log:  log.New("plugins.errors"),
+	}
+}
+
+func (r *SignatureErrorRegistry) Record(_ context.Context, signatureErr *plugins.SignatureError) {
+	r.errs[signatureErr.PluginID] = signatureErr
+}
+
+func (r *SignatureErrorRegistry) Clear(_ context.Context, pluginID string) {
+	delete(r.errs, pluginID)
+}
+
+func (r *SignatureErrorRegistry) SignatureErrors(_ context.Context) []*plugins.SignatureError {
+	errs := make([]*plugins.SignatureError, 0, len(r.errs))
+	for _, err := range r.errs {
+		errs = append(errs, err)
+	}
+	return errs
+}