Use state instead of multiple validators requests.

CHANGELOG.md

@@ -1,3 +1,6 @@
+0.19.8
+  - more efficient fetching for large numbers of validators
+
 0.19.7:
   - add endpoint metrics for prometheus
 

http/http.go

@@ -62,7 +62,7 @@ func (s *Service) post(ctx context.Context, endpoint string, body io.Reader) (io
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("Accept", "application/json")
 	if req.Header.Get("User-Agent") == "" {
-		req.Header.Set("User-Agent", "go-eth2-client/0.19.7")
+		req.Header.Set("User-Agent", "go-eth2-client/0.19.8")
 	}
 
 	resp, err := s.client.Do(req)
@@ -146,7 +146,7 @@ func (s *Service) post2(ctx context.Context,
 		req.Header.Set(k, v)
 	}
 	if req.Header.Get("User-Agent") == "" {
-		req.Header.Set("User-Agent", "go-eth2-client/0.19.7")
+		req.Header.Set("User-Agent", "go-eth2-client/0.19.8")
 	}
 
 	resp, err := s.client.Do(req)

http/validators.go

@@ -133,6 +133,11 @@ func (s *Service) Validators(ctx context.Context,
 		return s.validatorsFromState(ctx, opts)
 	}
 
+	if len(opts.Indices) > indexChunkSizes["default"]*2 || len(opts.PubKeys) > pubKeyChunkSizes["default"]*2 {
+		// Request is for multiple pages of validators; fetch from state.
+		return s.validatorsFromState(ctx, opts)
+	}
+
 	if len(opts.Indices) > s.indexChunkSize(ctx) || len(opts.PubKeys) > s.pubKeyChunkSize(ctx) {
 		return s.chunkedValidators(ctx, opts)
 	}
@@ -217,9 +222,33 @@ func (s *Service) validatorsFromState(ctx context.Context,
 		return nil, err
 	}
 
+	// Provide map of required pubkeys or indices.
+	indices := make(map[phase0.ValidatorIndex]struct{})
+	for _, index := range opts.Indices {
+		indices[index] = struct{}{}
+	}
+	pubkeys := make(map[phase0.BLSPubKey]struct{})
+	for _, pubkey := range opts.PubKeys {
+		pubkeys[pubkey] = struct{}{}
+	}
+
 	res := make(map[phase0.ValidatorIndex]*apiv1.Validator, len(validators))
 	for i, validator := range validators {
+		if len(pubkeys) > 0 {
+			if _, exists := pubkeys[validator.PublicKey]; !exists {
+				// We want specific public keys, and this isn't one of them.  Ignore.
+				continue
+			}
+		}
+
 		index := phase0.ValidatorIndex(i)
+		if len(indices) > 0 {
+			if _, exists := indices[index]; !exists {
+				// We want specific indices, and this isn't one of them.  Ignore.
+				continue
+			}
+		}
+
 		state := apiv1.ValidatorToState(validator, &balances[i], epoch, farFutureEpoch)
 		res[index] = &apiv1.Validator{
 			Index:     index,