[#493] node/config: Implement string caster

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

cmd/neofs-node/config/cast.go

@@ -28,3 +28,22 @@ func StringSlice(c *Config, name string) []string {
 func StringSliceSafe(c *Config, name string) []string {
 	return cast.ToStringSlice(c.Value(name))
 }
+
+// String reads configuration value
+// from c by name and casts it to string.
+//
+// Panics if value can not be casted.
+func String(c *Config, name string) string {
+	x, err := cast.ToStringE(c.Value(name))
+	panicOnErr(err)
+
+	return x
+}
+
+// StringSafe reads configuration value
+// from c by name and casts it to string.
+//
+// Returns "" if value can not be casted.
+func StringSafe(c *Config, name string) string {
+	return cast.ToString(c.Value(name))
+}

cmd/neofs-node/config/cast_test.go

@@ -28,3 +28,19 @@ func TestStringSlice(t *testing.T) {
 		require.Nil(t, val)
 	})
 }
+
+func TestString(t *testing.T) {
+	forEachFileType("test/config", func(c *config.Config) {
+		c = c.Sub("string")
+
+		val := config.String(c, "correct")
+		require.Equal(t, "some string", val)
+
+		require.Panics(t, func() {
+			config.String(c, "incorrect")
+		})
+
+		val = config.StringSafe(c, "incorrect")
+		require.Empty(t, val)
+	})
+}

cmd/neofs-node/config/test/config.json

@@ -10,5 +10,9 @@
       "string2"
     ],
     "incorrect": null
+  },
+  "string": {
+    "correct": "some string",
+    "incorrect": []
   }
 }

cmd/neofs-node/config/test/config.yaml

@@ -10,4 +10,9 @@ string_slice:
     - string1
     - string2
 
-  incorrect:
+  incorrect:
+
+string:
+  correct: some string
+
+  incorrect: []