[#493] node/config: Implement integer casters

Implement `Int` / `Uint` functions which casts value to `int64` / `uint64`.
Implement safe functions `IntSafe` / `UintSafe`.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

cmd/neofs-node/config/cast.go

@@ -68,3 +68,60 @@ func Duration(c *Config, name string) time.Duration {
 func DurationSafe(c *Config, name string) time.Duration {
 	return cast.ToDuration(c.Value(name))
 }
+
+// Bool reads configuration value
+// from c by name and casts it to bool.
+//
+// Panics if value can not be casted.
+func Bool(c *Config, name string) bool {
+	x, err := cast.ToBoolE(c.Value(name))
+	panicOnErr(err)
+
+	return x
+}
+
+// BoolSafe reads configuration value
+// from c by name and casts it to bool.
+//
+// Returns false if value can not be casted.
+func BoolSafe(c *Config, name string) bool {
+	return cast.ToBool(c.Value(name))
+}
+
+// Uint reads configuration value
+// from c by name and casts it to uint64.
+//
+// Panics if value can not be casted.
+func Uint(c *Config, name string) uint64 {
+	x, err := cast.ToUint64E(c.Value(name))
+	panicOnErr(err)
+
+	return x
+}
+
+// UintSafe reads configuration value
+// from c by name and casts it to uint64.
+//
+// Returns 0 if value can not be casted.
+func UintSafe(c *Config, name string) uint64 {
+	return cast.ToUint64(c.Value(name))
+}
+
+// Int reads configuration value
+// from c by name and casts it to int64.
+//
+// Panics if value can not be casted.
+func Int(c *Config, name string) int64 {
+	x, err := cast.ToInt64E(c.Value(name))
+	panicOnErr(err)
+
+	return x
+}
+
+// IntSafe reads configuration value
+// from c by name and casts it to int64.
+//
+// Returns 0 if value can not be casted.
+func IntSafe(c *Config, name string) int64 {
+	return cast.ToInt64(c.Value(name))
+}