chore: use json config

docker-compose.yml

@@ -0,0 +1,22 @@
+services:
+
+  server:
+    image: docker.io/nats:latest
+    ports:
+      - "4222:4222"
+      - "8222:8222"
+    volumes:
+      - server:/data
+    configs:
+      - source: sys.conf
+        target: /examples/sys.conf
+    command:
+      - '-c'
+      - '/examples/sys.conf'
+
+configs:
+  sys.conf:
+    file: './examples/sys.conf'
+
+volumes:
+  server:

examples/sys.conf

@@ -0,0 +1,4 @@
+{
+    "port": 4222,
+    "http_port": 8223
+}

pkg/config/config.go

@@ -1,20 +1,41 @@
 package config
 
+import (
+	"encoding/json"
+
+	"github.com/zeiss/pkg/cast"
+)
+
 // New returns a new Config object.
 func New() *Config {
 	return &Config{}
 }
 
+// Default ...
+func Default() *Config {
+	return &Config{
+		Host: cast.Ptr("0.0.0.0"),
+		Port: cast.Ptr(4222),
+	}
+}
+
 // Config ...
 type Config struct {
 	// Host ...
-	Host string `json:"host,omitempty"`
+	Host *string `json:"host,omitempty"`
 	// Port ...
 	Port *int `json:"port,omitempty"`
+	// HTTPPort ...
+	HTTPPort *int `json:"http_port,omitempty"`
 	// Gateway ...
 	Gateway *Gateway `json:"gateway,omitempty"`
 }
 
+// Marshal ...
+func (c *Config) Marshal() ([]byte, error) {
+	return json.Marshal(c)
+}
+
 // Gateway ...
 type Gateway struct {
 	// Name ...
@@ -56,11 +77,6 @@ type AuthCallout struct {
 	XKey string `json:"xkey"`
 }
 
-// Marhshal ...
-func (c *Config) Marshal() ([]byte, error) {
-	return nil, nil
-}
-
 // Property ...
 type Property struct {
 	// Name ...

pkg/config/config_test.go

@@ -13,3 +13,14 @@ func TestNew(t *testing.T) {
 	cfg := config.New()
 	require.NotNil(t, cfg)
 }
+
+func TestDefault(t *testing.T) {
+	t.Parallel()
+
+	cfg := config.Default()
+	require.NotNil(t, cfg)
+
+	json, err := cfg.Marshal()
+	require.NoError(t, err)
+	require.JSONEq(t, `{"host":"0.0.0.0","port":4222}`, string(json))
+}