[#1627] node: Add tree service to the config framework

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

cmd/neofs-node/config/tree/config.go

@@ -0,0 +1,53 @@
+package treeconfig
+
+import "github.com/nspcc-dev/neofs-node/cmd/neofs-node/config"
+
+const (
+	subsection = "tree"
+)
+
+// TreeConfig is a wrapper over "tree" config section
+// which provides access to the configuration of the tree service.
+type TreeConfig struct {
+	cfg *config.Config
+}
+
+// Tree returns structure that provides access to a "tree"
+// configuration subsection.
+func Tree(c *config.Config) TreeConfig {
+	return TreeConfig{
+		c.Sub(subsection),
+	}
+}
+
+// Enabled returns the value of "enabled" config parameter
+// from the "tree" section.
+//
+// Returns `false` if config value is not specified.
+func (c TreeConfig) Enabled() bool {
+	return config.BoolSafe(c.cfg, "enabled")
+}
+
+// CacheSize returns the value of "cache_size" config parameter
+// from the "tree" section.
+//
+// Returns `0` if config value is not specified.
+func (c TreeConfig) CacheSize() int {
+	return int(config.IntSafe(c.cfg, "cache_size"))
+}
+
+// ReplicationChannelCapacity returns the value of "replication_channel_capacity"
+// config parameter from the "tree" section.
+//
+// Returns `0` if config value is not specified.
+func (c TreeConfig) ReplicationChannelCapacity() int {
+	return int(config.IntSafe(c.cfg, "replication_channel_capacity"))
+}
+
+// ReplicationWorkerCount returns the value of "replication_worker_count"
+// config parameter from the "tree" section.
+//
+// Returns `0` if config value is not specified.
+func (c TreeConfig) ReplicationWorkerCount() int {
+	return int(config.IntSafe(c.cfg, "replication_worker_count"))
+}