Config file loading/validation implemented.

Builds, does not run!

config.go

@@ -0,0 +1,69 @@
+package inbucket
+
+import (
+	"container/list"
+	"fmt"
+	"github.com/robfig/goconfig/config"
+	"os"
+)
+
+var Config *config.Config
+
+// LoadConfig loads the specified configuration file into inbucket.Config
+// and performs validations on it.
+func LoadConfig(filename string) error {
+	var err error
+	Config, err = config.ReadDefault(filename)
+	if err != nil {
+		return err
+	}
+
+	messages := list.New()
+
+	// Validate sections
+	requireSection(messages, "smtp")
+	requireSection(messages, "web")
+	requireSection(messages, "datastore")
+	if messages.Len() > 0 {
+		fmt.Fprintln(os.Stderr, "Error(s) validating configuration:")
+		for e := messages.Front(); e != nil; e = e.Next() {
+			fmt.Fprintln(os.Stderr, " -", e.Value.(string))
+		}
+		return fmt.Errorf("Failed to validate configuration")
+	}
+
+	// Validate options
+	requireOption(messages, "smtp", "ip4.address")
+	requireOption(messages, "smtp", "ip4.port")
+	requireOption(messages, "smtp", "domain")
+	requireOption(messages, "web", "ip4.address")
+	requireOption(messages, "web", "ip4.port")
+	requireOption(messages, "web", "templates.dir")
+	requireOption(messages, "web", "public.dir")
+	requireOption(messages, "datastore", "path")
+	if messages.Len() > 0 {
+		fmt.Fprintln(os.Stderr, "Error(s) validating configuration:")
+		for e := messages.Front(); e != nil; e = e.Next() {
+			fmt.Fprintln(os.Stderr, " -", e.Value.(string))
+		}
+		return fmt.Errorf("Failed to validate configuration")
+	}
+
+	return nil
+}
+
+// requireSection checks that a [section] is defined in the configuration file,
+// appending a message if not.
+func requireSection(messages *list.List, section string) {
+	if !Config.HasSection(section) {
+		messages.PushBack(fmt.Sprintf("Config section [%v] is required", section))
+	}
+}
+
+// requireOption checks that 'option' is defined in [section] of the config file,
+// appending a message if not.
+func requireOption(messages *list.List, section string, option string) {
+	if !Config.HasOption(section, option) {
+		messages.PushBack(fmt.Sprintf("Config option '%v' is required in section [%v]", option, section))
+	}
+}