vault: poll for DKG result in NewReportingPlugin (~12s startup speedup) (#21710)

vault: poll for DKG result in NewReportingPlugin instead of failing immediately

When the vault OCR3.1 oracle starts before DKG completes, NewReportingPlugin
fails because the DKG result package is not yet in the database. This triggers
libocr exponential backoff (1s, 2s, 4s, 8s... up to 2min), wasting ~12s even
after the DKG result becomes available.

Add pollForKeyMaterial() that polls the DB every 2s within the
MaxDurationInitialization context window (10s). The vault oracle now starts
within seconds of DKG completion instead of waiting for the next retry cycle.

Made-with: Cursor

Author: prashantkumar1982

core/services/ocr2/plugins/vault/plugin.go

@@ -12,6 +12,7 @@ import (
 	"regexp"
 	"slices"
 	"sort"
+	"time"
 
 	"golang.org/x/crypto/curve25519"
 	"golang.org/x/crypto/nacl/box"
@@ -136,6 +137,31 @@ func (r *ReportingPluginFactory) getKeyMaterial(ctx context.Context, instanceID
 	return publicKey, privateKeyShare, nil
 }
 
+const dkgPollInterval = 2 * time.Second
+
+// pollForKeyMaterial polls the DKG result package database until the key
+// material for the given instance ID is available or the context is cancelled.
+// This avoids returning an immediate error when the DKG protocol hasn't
+// completed yet, which would trigger libocr's exponential backoff (up to 2
+// minutes between retries). By polling here within the MaxDurationInitialization
+// window, the vault oracle can start as soon as the DKG result is written.
+func (r *ReportingPluginFactory) pollForKeyMaterial(ctx context.Context, instanceID string) (publicKey *tdh2easy.PublicKey, privateKeyShare *tdh2easy.PrivateShare, err error) {
+	for {
+		publicKey, privateKeyShare, err = r.getKeyMaterial(ctx, instanceID)
+		if err == nil {
+			return publicKey, privateKeyShare, nil
+		}
+
+		r.lggr.Debugw("DKG result package not yet available, will retry", "instanceID", instanceID, "error", err)
+
+		select {
+		case <-ctx.Done():
+			return nil, nil, fmt.Errorf("context cancelled while waiting for DKG key material (instanceID=%s): %w", instanceID, err)
+		case <-time.After(dkgPollInterval):
+		}
+	}
+}
+
 func initializePluginLimits(ctx context.Context, limitsFactory limits.Factory) (ocr3_1types.ReportingPluginLimits, error) {
 	maxQueryBytes, err := cresettings.Default.VaultMaxQuerySizeLimit.GetOrDefault(ctx, limitsFactory.Settings)
 	if err != nil {
@@ -277,7 +303,7 @@ func (r *ReportingPluginFactory) NewReportingPlugin(ctx context.Context, config
 	}
 
 	r.lggr.Debugw("fetching key material for instance id", "instanceID", *configProto.DKGInstanceID)
-	publicKey, privateKeyShare, err := r.getKeyMaterial(ctx, *configProto.DKGInstanceID)
+	publicKey, privateKeyShare, err := r.pollForKeyMaterial(ctx, *configProto.DKGInstanceID)
 	if err != nil {
 		return nil, ocr3_1types.ReportingPluginInfo1{}, fmt.Errorf("could not get key material from DB: %w", err)
 	}