automatically create the parent path of the db if missing

Makefile

@@ -1,3 +1,5 @@
+.PHONY: help test build run clean
+
 GO_FLAGS   ?=
 NAME       := fan2go
 OUTPUT_BIN ?= bin/${NAME}

README.md

@@ -37,7 +37,8 @@
 
 # UI
 
-fan2go is a simple terminal client and controller daemon. To allow external programs to interact with it there is an API that
+fan2go is a simple terminal client and controller daemon. To allow external programs to interact with it there is an API
+that
 can be (optionally) enabled.
 
 ## UI Clients
@@ -484,6 +485,9 @@ sudo systemctl enable --now fan2go
 journalctl -u fan2go -f
 ```
 
+> NOTE: If you want to use a config path that differs from the default one, make sure to edit the
+> unit file and point the `-c` flag to the correct path.
+
 ## CLI Commands
 
 Although fan2go is a fan controller daemon at heart, it also provides some handy cli commands to interact with the

internal/controller/controller.go

@@ -97,6 +97,11 @@ func (f *PidFanController) GetStatistics() FanControllerStatistics {
 }
 
 func (f *PidFanController) Run(ctx context.Context) error {
+	err := f.persistence.Init()
+	if err != nil {
+		return err
+	}
+
 	fan := f.fan
 
 	if fan.ShouldNeverStop() && !fan.Supports(fans.FeatureRpmSensor) {

internal/controller/controller_test.go

@@ -203,6 +203,8 @@ var (
 
 type mockPersistence struct{}
 
+func (p mockPersistence) Init() (err error) { return nil }
+
 func (p mockPersistence) SaveFanPwmData(fan fans.Fan) (err error) { return nil }
 func (p mockPersistence) LoadFanPwmData(fan fans.Fan) (map[int]float64, error) {
 	fanCurveDataMap := map[int]float64{}

internal/persistence/persistence.go

@@ -2,11 +2,13 @@ package persistence
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"github.com/markusressel/fan2go/internal/fans"
 	"github.com/markusressel/fan2go/internal/ui"
 	bolt "go.etcd.io/bbolt"
 	"os"
+	"path/filepath"
 	"time"
 )
 
@@ -16,6 +18,8 @@ const (
 )
 
 type Persistence interface {
+	Init() error
+
 	LoadFanPwmData(fan fans.Fan) (map[int]float64, error)
 	SaveFanPwmData(fan fans.Fan) (err error)
 	DeleteFanPwmData(fan fans.Fan) (err error)
@@ -36,6 +40,21 @@ func NewPersistence(dbPath string) Persistence {
 	return p
 }
 
+func (p persistence) Init() (err error) {
+	// get parent path of dbPath
+	parentDir := filepath.Dir(p.dbPath)
+	_, err = os.Stat(parentDir)
+	if errors.Is(err, os.ErrNotExist) {
+		// create directory
+		ui.Info("Creating directory for db: %s", parentDir)
+		err = os.MkdirAll(parentDir, 0755)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (p persistence) openPersistence() (db *bolt.DB, err error) {
 	db, err = bolt.Open(p.dbPath, 0600, &bolt.Options{Timeout: 1 * time.Minute})
 	if err != nil {