Ensure collectd uses defaults with partial config

services/collectd/config.go

@@ -42,3 +42,28 @@ func NewConfig() Config {
 		TypesDB:         DefaultTypesDB,
 	}
 }
+
+// WithDefaults takes the given config and returns a new config with any required
+// default values set.
+func (c *Config) WithDefaults() *Config {
+	d := *c
+	if d.BindAddress == "" {
+		d.BindAddress = DefaultBindAddress
+	}
+	if d.Database == "" {
+		d.Database = DefaultDatabase
+	}
+	if d.RetentionPolicy == "" {
+		d.RetentionPolicy = DefaultRetentionPolicy
+	}
+	if d.BatchSize == 0 {
+		d.BatchSize = DefaultBatchSize
+	}
+	if d.BatchDuration == 0 {
+		d.BatchDuration = DefaultBatchDuration
+	}
+	if d.TypesDB == "" {
+		d.TypesDB = DefaultTypesDB
+	}
+	return &d
+}

services/collectd/service.go

@@ -47,7 +47,7 @@ type Service struct {
 // NewService returns a new instance of the collectd service.
 func NewService(c Config) *Service {
 	s := &Service{
-		Config: &c,
+		Config: c.WithDefaults(),
 		Logger: log.New(os.Stderr, "[collectd] ", log.LstdFlags),
 		err:    make(chan error),
 	}