Configuration verification before it's passed along (#42)

* Configuration verification before it's passed along

* fixed spaces

configuration/configuration.go

@@ -2,6 +2,7 @@ package configuration
 
 import (
 	"os"
+	"reflect"
 
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
@@ -41,6 +42,7 @@ func (c *Configuration) GetConfiguration() *Configuration {
 	if err != nil {
 		logrus.Fatal("Following error reading from config file", err)
 	}
+
 	err = viper.Unmarshal(&c)
 	if err != nil {
 		logrus.Fatal("Error structuring configuration", err)
@@ -49,9 +51,41 @@ func (c *Configuration) GetConfiguration() *Configuration {
 	if c.DownloadDir == "" {
 		c.DownloadDir = "/tmp/syncron/"
 	}
+	checkConfig(*c)
 
 	logrus.Info("Your configuration file was read succesfully")
 	logrus.Info("Reading from bucket: ", c.S3.Bucket)
 
 	return c
 }
+
+// This function checks a Configuration struct and its embedded S3 struct for empty fields.
+// It does this by using the reflect package to get the values and types.
+func checkConfig(c Configuration) {
+
+	values := reflect.ValueOf(c)
+	valuesS3 := reflect.ValueOf(c.S3)
+
+	//Check if struct that holds configuration is empty
+	if reflect.ValueOf(c).IsZero() {
+		logrus.Fatal("Configuration struct appears to be empty")
+	}
+
+	typesS3 := valuesS3.Type()
+	types := values.Type()
+
+	// Check for configuration struct fields
+	for i := 0; i < valuesS3.NumField(); i++ {
+		if valuesS3.Field(i).IsZero() {
+			logrus.Fatal(typesS3.Field(i).Name, " field in config appears to be empty")
+		}
+	}
+
+	// Check for S3 struct fields
+	for i := 0; i < values.NumField(); i++ {
+		if values.Field(i).IsZero() {
+			logrus.Fatal(types.Field(i).Name, " field in config appears to be empty")
+		}
+	}
+
+}