refactor config to use functional options pattern

2 files changed, 44 insertions, 8 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
index cb144f3..988315a 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -24,7 +24,7 @@ type Config struct {
 	SMTPServer      string `json:"SMTPServer,omitempty"`
 }
 
-func New(configFile string) (Config, error) {
+func NewFromConfigFile(configFile string) (Config, error) {
 	var conf Config
 
 	file, err := os.Open(configFile)
@@ -43,14 +43,50 @@ func New(configFile string) (Config, error) {
 		return conf, err
 	}
 
-	return NewFromConfig(conf)
+	return conf.setDefaults()
 }
 
-func NewFromConfig(conf Config) (Config, error) {
-	return conf.initialize()
+func New(options ...func(*Config)) (Config, error) {
+	var conf Config
+
+	for _, opt := range options {
+		opt(&conf)
+	}
+
+	return conf.setDefaults()
+}
+
+func WithStateDir(stateDir string) func(*Config) {
+	return func(conf *Config) {
+		conf.StateDir = stateDir
+	}
+}
+
+func WithAddress(address string) func(*Config) {
+	return func(conf *Config) {
+		conf.Address = address
+	}
+}
+
+func WithNodes(nodes ...string) func(*Config) {
+	return func(conf *Config) {
+		conf.Nodes = append(conf.Nodes, nodes...)
+	}
+}
+
+func WithMyID(id string) func(*Config) {
+	return func(conf *Config) {
+		conf.MyID = id
+	}
+}
+
+func WithRelaxedMode() func(*Config) {
+	return func(conf *Config) {
+		conf.RelaxedMode = true
+	}
 }
 
-func (conf Config) initialize() (Config, error) {
+func (conf Config) setDefaults() (Config, error) {
 	if conf.LoopIntervalS == 0 {
 		conf.LoopIntervalS = 10
 	}
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index 96d4998..e24c048 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -8,7 +8,7 @@ import (
 
 func TestNodeNumber(t *testing.T) {
 	t.Parallel()
-	conf, _ := NewFromConfig(Config{Nodes: []string{"localhost:1234", "hamburger:4321"}})
+	conf, _ := New(WithNodes("localhost:1234", "hamburger:4321"))
 
 	num := conf.NodeNumber("localhost")
 	if num != 0 {
@@ -23,7 +23,7 @@ func TestNodeNumber(t *testing.T) {
 
 func TestIsNode(t *testing.T) {
 	t.Parallel()
-	conf, _ := NewFromConfig(Config{Nodes: []string{"localhost:1234", "hamburger:4321"}})
+	conf, _ := New(WithNodes("localhost:1234", "hamburger:4321"))
 
 	remoteAddr := "localhost:323232"
 	if !conf.IsNode(remoteAddr) {
@@ -38,7 +38,7 @@ func TestIsNode(t *testing.T) {
 
 func TestIsNodeWithLookup(t *testing.T) {
 	t.Parallel()
-	conf, _ := NewFromConfig(Config{Nodes: []string{"localhost:1234", "hamburger:4321"}})
+	conf, _ := New(WithNodes("localhost:1234", "hamburger:4321"))
 
 	lookupIP := func(addr string) ([]net.IP, error) {
 		switch addr {