Hoist control for exiting script a level up (#348)

* Hoist control for exiting script a level up

* Do not accidentally nil out errors

* Log when running schedule

* Remove duplicate log line

* Warn on cron schedule that will never run

cmd/backup/config_provider.go

@@ -38,7 +38,7 @@ func loadConfig(lookup envProxy) (*Config, error) {
 
 	var c = &Config{}
 	if err := envconfig.Process("", c); err != nil {
-		return nil, fmt.Errorf("failed to process configuration values, error: %w", err)
+		return nil, fmt.Errorf("loadConfig: failed to process configuration values: %w", err)
 	}
 
 	return c, nil
@@ -48,33 +48,39 @@ func loadEnvVars() (*Config, error) {
 	return loadConfig(os.LookupEnv)
 }
 
-func loadEnvFiles(directory string) ([]*Config, error) {
+type configFile struct {
+	name   string
+	config *Config
+}
+
+func loadEnvFiles(directory string) ([]configFile, error) {
 	items, err := os.ReadDir(directory)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil, err
 		}
-		return nil, fmt.Errorf("failed to read files from env directory, error: %w", err)
+		return nil, fmt.Errorf("loadEnvFiles: failed to read files from env directory: %w", err)
 	}
 
-	var cs = make([]*Config, 0)
+	cs := []configFile{}
 	for _, item := range items {
-		if !item.IsDir() {
-			p := filepath.Join(directory, item.Name())
-			envFile, err := godotenv.Read(p)
-			if err != nil {
-				return nil, fmt.Errorf("error reading config file %s, error: %w", p, err)
-			}
-			lookup := func(key string) (string, bool) {
-				val, ok := envFile[key]
-				return val, ok
-			}
-			c, err := loadConfig(lookup)
-			if err != nil {
-				return nil, fmt.Errorf("error loading config from file %s, error: %w", p, err)
-			}
-			cs = append(cs, c)
+		if item.IsDir() {
+			continue
+		}
+		p := filepath.Join(directory, item.Name())
+		envFile, err := godotenv.Read(p)
+		if err != nil {
+			return nil, fmt.Errorf("loadEnvFiles: error reading config file %s: %w", p, err)
+		}
+		lookup := func(key string) (string, bool) {
+			val, ok := envFile[key]
+			return val, ok
+		}
+		c, err := loadConfig(lookup)
+		if err != nil {
+			return nil, fmt.Errorf("loadEnvFiles: error loading config from file %s: %w", p, err)
 		}
+		cs = append(cs, configFile{config: c, name: item.Name()})
 	}
 
 	return cs, nil

cmd/backup/cron.go

@@ -0,0 +1,29 @@
+// Copyright 2024 - Offen Authors <[email protected]>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"time"
+
+	"github.com/robfig/cron/v3"
+)
+
+// checkCronSchedule detects whether the given cron expression will actually
+// ever be executed or not.
+func checkCronSchedule(expression string) (ok bool) {
+	defer func() {
+		if err := recover(); err != nil {
+			ok = false
+		}
+	}()
+	sched, err := cron.ParseStandard(expression)
+	if err != nil {
+		ok = false
+		return
+	}
+	now := time.Now()
+	sched.Next(now) // panics when the cron would never run
+	ok = true
+	return
+}

cmd/backup/exec.go

@@ -188,13 +188,18 @@ func (s *script) withLabeledCommands(step lifecyclePhase, cb func() error) func(
 	if s.cli == nil {
 		return cb
 	}
-	return func() error {
-		if err := s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-pre", step)); err != nil {
-			return fmt.Errorf("withLabeledCommands: %s: error running pre commands: %w", step, err)
+	return func() (err error) {
+		if err = s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-pre", step)); err != nil {
+			err = fmt.Errorf("withLabeledCommands: %s: error running pre commands: %w", step, err)
+			return
 		}
 		defer func() {
-			s.must(s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-post", step)))
+			derr := s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-post", step))
+			if err == nil && derr != nil {
+				err = derr
+			}
 		}()
-		return cb()
+		err = cb()
+		return
 	}
 }