fix: handle zero rpc concurrency gracefully

Warn instead of panicking, so we can re-use configuration between Pro and OSS versions

Author: palkan

rpc/config.go

@@ -15,6 +15,8 @@ import (
 
 const (
 	defaultRPCHost = "localhost:50051"
+	// Slightly less than default Ruby gRPC server concurrency
+	defaultRPCConcurrency = 28
 )
 
 // ClientHelper provides additional methods to operate gRPC client
@@ -61,7 +63,7 @@ type Config struct {
 // NewConfig builds a new config
 func NewConfig() Config {
 	return Config{
-		Concurrency:    28,
+		Concurrency:    defaultRPCConcurrency,
 		EnableTLS:      false,
 		TLSVerify:      true,
 		Host:           defaultRPCHost,

rpc/rpc.go

@@ -172,6 +172,10 @@ func NewController(metrics metrics.Instrumenter, config *Config, l *slog.Logger)
 	metrics.RegisterGauge(metricsRPCPending, "The number of pending RPC calls")
 
 	capacity := config.Concurrency
+	if capacity <= 0 {
+		capacity = defaultRPCConcurrency
+		l.Warn("RPC concurrency must be positive, reverted to the default value")
+	}
 	barrier, err := NewFixedSizeBarrier(capacity)
 
 	if err != nil {