Added docs and better error propagation

offen · Feb 6, 2024 · 950474e · 950474e
1 parent 701d2bb
commit 950474e
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Showing 3 changed files with 79 additions and 58 deletions.
diff --git a/cmd/backup/config_provider.go b/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: %v", err)
+		return nil, fmt.Errorf("failed to process configuration values, error: %w", err)
 	}
 
 	return c, nil
@@ -54,7 +54,7 @@ func loadEnvFiles(directory string) ([]*Config, error) {
 		if os.IsNotExist(err) {
 			return nil, err
 		}
-		return nil, fmt.Errorf("failed to read files from env directory, error: %v", err)
+		return nil, fmt.Errorf("failed to read files from env directory, error: %w", err)
 	}
 
 	var cs = make([]*Config, 0)
@@ -63,15 +63,15 @@ func loadEnvFiles(directory string) ([]*Config, error) {
 			p := filepath.Join(directory, item.Name())
 			envFile, err := godotenv.Read(p)
 			if err != nil {
-				return nil, fmt.Errorf("error reading config file %s, error: %v", p, err)
+				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: %v", p, err)
+				return nil, fmt.Errorf("error loading config from file %s, error: %w", p, err)
 			}
 			cs = append(cs, c)
 		}

diff --git a/cmd/backup/main.go b/cmd/backup/main.go
@@ -14,7 +14,7 @@ import (
 	"github.com/robfig/cron/v3"
 )
 
-func runBackup(c *Config) (ret error) {
+func runScript(c *Config) (ret error) {
 	s, err := newScript(c)
 	if err != nil {
 		return err
@@ -86,66 +86,68 @@ func runBackup(c *Config) (ret error) {
 	return nil
 }
 
-func app(serve bool) error {
-	if serve {
-		cr := cron.New(
-			cron.WithParser(
-				cron.NewParser(
-					cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor,
-				),
+func runInForeground() error {
+	cr := cron.New(
+		cron.WithParser(
+			cron.NewParser(
+				cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor,
 			),
-		)
+		),
+	)
 
-		addJob := func(c *Config) error {
-			_, err := cr.AddFunc(c.BackupCronExpression, func() {
-				err := runBackup(c)
-				if err != nil {
-					slog.Error("unexpected error during backup", "error", err)
-				}
-			})
-			return err
+	addJob := func(c *Config) error {
+		_, err := cr.AddFunc(c.BackupCronExpression, func() {
+			err := runScript(c)
+			if err != nil {
+				slog.Error("unexpected error during backup", "error", err)
+			}
+		})
+		return err
+	}
+
+	cs, err := loadEnvFiles("/etc/dockervolumebackup/conf.d")
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return fmt.Errorf("could not load config from environment files, error: %w", err)
 		}
 
-		cs, err := loadEnvFiles("/etc/dockervolumebackup/conf.d")
+		c, err := loadEnvVars()
 		if err != nil {
-			if !os.IsNotExist(err) {
-				return fmt.Errorf("could not load config from environment files, error: %v", err)
-			}
-
-			c, err := loadEnvVars()
-			if err != nil {
-				return fmt.Errorf("could not load config from environment variables")
-			} else {
-				err = addJob(c)
-				if err != nil {
-					return fmt.Errorf("could not add cron job, error: %v", err)
-				}
-			}
+			return fmt.Errorf("could not load config from environment variables")
 		} else {
-			for _, c := range cs {
-				err = addJob(c)
-				if err != nil {
-					return fmt.Errorf("could not add cron job, error: %v", err)
-				}
+			err = addJob(c)
+			if err != nil {
+				return fmt.Errorf("could not add cron job, error: %w", err)
 			}
 		}
-
-		var quit = make(chan os.Signal, 1)
-		signal.Notify(quit, syscall.SIGTERM, syscall.SIGINT)
-		cr.Start()
-		<-quit
-		ctx := cr.Stop()
-		<-ctx.Done()
 	} else {
-		c, err := loadEnvVars()
-		if err != nil {
-			return fmt.Errorf("could not load config from environment variables, error: %v", err)
+		for _, c := range cs {
+			err = addJob(c)
+			if err != nil {
+				return fmt.Errorf("could not add cron job, error: %w", err)
+			}
 		}
+	}
 
-		err = runBackup(c)
-		if err != nil {
-			return fmt.Errorf("unexpected error during backup, error: %v", err)
-		}
+	var quit = make(chan os.Signal, 1)
+	signal.Notify(quit, syscall.SIGTERM, syscall.SIGINT)
+	cr.Start()
+	<-quit
+	ctx := cr.Stop()
+	<-ctx.Done()
+
+	return nil
+}
+
+func runAsCommand() error {
+	c, err := loadEnvVars()
+	if err != nil {
+		return fmt.Errorf("could not load config from environment variables, error: %w", err)
+	}
+
+	err = runScript(c)
+	if err != nil {
+		return fmt.Errorf("unexpected error during backup, error: %w", err)
 	}
 
 	return nil
@@ -155,7 +157,13 @@ func main() {
 	serve := flag.Bool("foreground", false, "run the tool in the foreground")
 	flag.Parse()
 
-	err := app(*serve)
+	var err error
+	if *serve {
+		err = runInForeground()
+	} else {
+		err = runAsCommand()
+	}
+
 	if err != nil {
 		slog.Error("ran into an issue during execution", "error", err)
 		os.Exit(1)

diff --git a/docs/reference/index.md b/docs/reference/index.md
@@ -23,9 +23,22 @@ You can populate below template according to your requirements and use it as you
 ```
 ########### BACKUP SCHEDULE
 
-# Backups run on the given cron schedule in `busybox` flavor. If no
-# value is set, `@daily` will be used. If you do not want the cron
-# to ever run, use `0 0 5 31 2 ?`.
+
+# A cron expression represents a set of times, using 5 or 6 space-separated fields.
+#
+# Field name   | Mandatory? | Allowed values  | Allowed special characters
+# ----------   | ---------- | --------------  | --------------------------
+# Seconds      | No         | 0-59            | * / , -
+# Minutes      | Yes        | 0-59            | * / , -
+# Hours        | Yes        | 0-23            | * / , -
+# Day of month | Yes        | 1-31            | * / , - ?
+# Month        | Yes        | 1-12 or JAN-DEC | * / , -
+# Day of week  | Yes        | 0-6 or SUN-SAT  | * / , - ?
+#
+# Month and Day-of-week field values are case insensitive.
+# "SUN", "Sun", and "sun" are equally accepted.
+# If no value is set, `@daily` will be used.
+# If you do not want the cron to ever run, use `0 0 5 31 2 ?`.
 
 # BACKUP_CRON_EXPRESSION="0 2 * * *"