Add configuration via env vars

config.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+
+	"github.com/rs/zerolog"
+)
+
+type Config struct {
+	logLevel     zerolog.Level
+	rootPath     string
+	numOfWorkers int
+}
+
+func getConfig() *Config {
+	var config Config
+	for _, envVar := range []string{
+		"LOG_LEVEL",
+		"ROOT_PATH",
+		"NUM_OF_WORKERS",
+	} {
+		if env, ok := os.LookupEnv(envVar); !ok {
+			fmt.Fprintf(os.Stderr, "Missing env var %s\n", envVar)
+			os.Exit(1)
+		} else {
+			switch envVar {
+			case "LOG_LEVEL":
+				{
+					logLevel, err := zerolog.ParseLevel(env)
+					if err != nil {
+						fmt.Fprintf(os.Stderr, "Invalid LOG_LEVEL value\n")
+						os.Exit(1)
+					}
+					config.logLevel = logLevel
+				}
+			case "ROOT_PATH":
+				{
+					config.rootPath = env
+				}
+			case "NUM_OF_WORKERS":
+				{
+					if numOfWorkers, err := strconv.Atoi(env); err != nil {
+						fmt.Fprintf(os.Stderr, "Invalid NUM_OF_WORKERS value\n")
+						os.Exit(1)
+					} else {
+						config.numOfWorkers = numOfWorkers
+					}
+				}
+			}
+		}
+	}
+	return &config
+}