Added check for configuration

config/config.go

@@ -1,11 +1,17 @@
 package config // import "github.com/Luzifer/mondash/config"
 
 import (
+	"fmt"
+	"log"
+	"net/url"
 	"os"
+	"strings"
 
 	"github.com/spf13/pflag"
 )
 
+var storageDrivers = []string{"s3", "file"}
+
 // Config is a storage struct for configuration parameters
 type Config struct {
 	Storage  string
@@ -26,7 +32,7 @@ type Config struct {
 // Load parses arguments / ENV variable to load configuration
 func Load() *Config {
 	cfg := &Config{}
-	pflag.StringVar(&cfg.Storage, "storage", "s3", "Storage engine to use (s3, file)")
+	pflag.StringVar(&cfg.Storage, "storage", "s3", fmt.Sprintf("Storage engine to use (%s)", strings.Join(storageDrivers, ", ")))
 	pflag.StringVar(&cfg.BaseURL, "baseurl", os.Getenv("BASE_URL"), "The Base-URL the application is running on for example https://mondash.org")
 	pflag.StringVar(&cfg.APIToken, "api-token", os.Getenv("API_TOKEN"), "API Token used for the /welcome dashboard (you can choose your own)")
 	pflag.StringVar(&cfg.Listen, "listen", ":3000", "Address to listen on")
@@ -40,3 +46,32 @@ func Load() *Config {
 	pflag.Parse()
 	return cfg
 }
+
+func (c Config) isValid() bool {
+	// Storage Driver check
+	validStoragedriver := false
+	for _, d := range storageDrivers {
+		if c.Storage == d {
+			validStoragedriver = true
+			break
+		}
+	}
+	if !validStoragedriver {
+		log.Printf("You specified a wrong storage driver: %s\n\n", c.Storage)
+		return false
+	}
+
+	// Minimum characters of API token
+	if len(c.APIToken) < 10 {
+		log.Printf("You need to specify an api-token with more than 9 characters.\n\n")
+		return false
+	}
+
+	// Base-URL check
+	if _, err := url.Parse(c.BaseURL); err != nil {
+		log.Printf("The baseurl '%s' does not look like a valid URL: %s.\n\n", c.BaseURL, err)
+		return false
+	}
+
+	return true
+}