add support for more config locations

now support /etc/docker-db-backup/config.yaml aside from current directiry

config.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"os"
+
+	"github.com/knadh/koanf/parsers/yaml"
+	"github.com/knadh/koanf/providers/file"
+	"github.com/knadh/koanf/v2"
+	"github.com/rotisserie/eris"
+	log "github.com/sirupsen/logrus"
+)
+
+// Global koanf instance. Use "." as the key path delimiter. This can be "/" or any character.
+var k = koanf.New(".")
+
+// loadConfigFile loads the config file from the current directory and /etc/docker-db-backup/config.yaml
+func loadConfigFile() {
+	configPath := "config.yaml"
+
+	if checkIfFileExists("config.yaml") {
+		// do nothing
+	} else if checkIfFileExists("/etc/docker-db-backup/config.yaml") {
+		configPath = "/etc/docker-db-backup/config.yaml"
+	} else {
+		log.Fatal("Config file not found")
+	}
+
+	log.Infof("Loading config file: %s", configPath)
+
+	// Load yaml config.
+	if err := k.Load(file.Provider(configPath), yaml.Parser()); err != nil {
+		log.Fatal(eris.Wrap(err, "failed to load config"))
+	}
+}
+
+// utility function to check if a file exists
+func checkIfFileExists(path string) bool {
+	// based on
+	// https://stackoverflow.com/questions/12518876/how-to-check-if-a-file-exists-in-go
+	if _, err := os.Stat(path); err == nil {
+		// path/to/whatever exists
+		return true
+	} else if eris.Is(err, os.ErrNotExist) {
+		// path/to/whatever does *not* exist
+		return false
+	} else {
+		// Schrodinger: file may or may not exist. See err for details.
+
+		// Therefore, do *NOT* use !os.IsNotExist(err) to test for file existence
+		return false
+	}
+
+	// return false
+}

main.go

@@ -11,9 +11,6 @@ import (
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/client"
 	"github.com/go-co-op/gocron/v2"
-	"github.com/knadh/koanf/parsers/yaml"
-	"github.com/knadh/koanf/providers/file"
-	"github.com/knadh/koanf/v2"
 	"github.com/rotisserie/eris"
 	log "github.com/sirupsen/logrus"
 )
@@ -23,9 +20,6 @@ type JobConfig struct {
 	Config map[string]string
 }
 
-// Global koanf instance. Use "." as the key path delimiter. This can be "/" or any character.
-var k = koanf.New(".")
-
 func init() {
 	// Log as JSON instead of the default ASCII formatter.
 	// log.SetFormatter(&log.JSONFormatter{})
@@ -43,10 +37,8 @@ func init() {
 func main() {
 	log.Info("Starting backup service")
 
-	// Load yaml config.
-	if err := k.Load(file.Provider("config.yaml"), yaml.Parser()); err != nil {
-		log.Fatal(eris.Wrap(err, "failed to load config"))
-	}
+	// load config file
+	loadConfigFile()
 
 	// create backup folder
 	createBackupFolder()