[#493] cmd/node: Add policer section to config

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

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

@@ -0,0 +1,27 @@
+package policerconfig
+
+import (
+	"time"
+
+	"github.com/nspcc-dev/neofs-node/cmd/neofs-node/config"
+)
+
+const (
+	subsection = "policer"
+
+	// HeadTimeoutDefault is a default object.Head request timeout in policer.
+	HeadTimeoutDefault = 5 * time.Second
+)
+
+// HeadTimeout returns value of "head_timeout" config parameter
+// from "policer" section.
+//
+// Returns HeadTimeoutDefault if value is not positive duration.
+func HeadTimeout(c *config.Config) time.Duration {
+	v := config.DurationSafe(c.Sub(subsection), "head_timeout")
+	if v > 0 {
+		return v
+	}
+
+	return HeadTimeoutDefault
+}