[#486] innerring: Add fee configuration

When notary disabled, inner ring should be able to
configure extra fee for vote collections inside the
contracts. Previously these values were hardcoded,
however we might want to change them depending on
a environment.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

cmd/neofs-ir/defaults.go

@@ -117,4 +117,8 @@ func defaultConfiguration(cfg *viper.Viper) {
 	cfg.SetDefault("indexer.cache_timeout", 15*time.Second)
 
 	cfg.SetDefault("locode.db.path", "")
+
+	// extra fee values for working mode without notary contract
+	cfg.SetDefault("fee.main_chain", 5000_0000)   // 0.5 Fixed8
+	cfg.SetDefault("fee.side_chain", 2_0000_0000) // 2.0 Fixed8
 }

pkg/innerring/config/fee.go

@@ -0,0 +1,27 @@
+package config
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/encoding/fixedn"
+	"github.com/spf13/viper"
+)
+
+// FeeConfig is an instance that returns extra fee values for contract
+// invocations without notary support.
+type FeeConfig struct {
+	mainchain, sidechain fixedn.Fixed8
+}
+
+func NewFeeConfig(v *viper.Viper) *FeeConfig {
+	return &FeeConfig{
+		mainchain: fixedn.Fixed8(v.GetInt64("fee.main_chain")),
+		sidechain: fixedn.Fixed8(v.GetInt64("fee.side_chain")),
+	}
+}
+
+func (f FeeConfig) MainChainFee() fixedn.Fixed8 {
+	return f.mainchain
+}
+
+func (f FeeConfig) SideChainFee() fixedn.Fixed8 {
+	return f.sidechain
+}