feat(backend): add init option to backend config

When this option is set to `true`, the backend will automatically get
initialized during the backup process. This applies to invoking
`autorestic backup` or when `autorestic cron` actualy performs a backup.

docs/pages/backend/index.md

@@ -38,3 +38,19 @@ backends:
 ```
 
 With this setting, if a key is missing, `autorestic` will crash instead of generating a new key and updating your config file.
+
+## Automatic Backend Initialization
+
+`autorestic` is able to automatically initialize backends for you. This is done by setting `init: true` in the config for a given backend. For example:
+
+```yaml | .autorestic.yml
+backend:
+  foo:
+    type: ...
+    path: ...
+    init: true
+```
+
+When you set `init: true` on a backend config, `autorestic` will automatically initialize the underlying `restic` repository that powers the backend if it's not already initialized. In practice, this means that the backend will be initialized the first time it is being backed up to.
+
+This option is helpful in cases where you want to automate the configuration of `autorestic`. This means that instead of running `autorestic exec init -b ...` manually when you create a new backend, you can let `autorestic` initialize it for you.

internal/backend.go

@@ -24,6 +24,7 @@ type Backend struct {
 	Path       string            `mapstructure:"path,omitempty"`
 	Key        string            `mapstructure:"key,omitempty"`
 	RequireKey bool              `mapstructure:"requireKey,omitempty"`
+	Init       bool              `mapstructure:"init,omitempty"`
 	Env        map[string]string `mapstructure:"env,omitempty"`
 	Rest       BackendRest       `mapstructure:"rest,omitempty"`
 	Options    Options           `mapstructure:"options,omitempty"`
@@ -130,20 +131,44 @@ func (b Backend) validate() error {
 		return err
 	}
 	options := ExecuteOptions{Envs: env, Silent: true}
-	// Check if already initialized
+
+	err = b.EnsureInit()
+	if err != nil {
+		return err
+	}
+
 	cmd := []string{"check"}
 	cmd = append(cmd, combineBackendOptions("check", b)...)
 	_, _, err = ExecuteResticCommand(options, cmd...)
-	if err == nil {
-		return nil
-	} else {
-		// If not initialize
+	return err
+}
+
+// EnsureInit initializes the backend if it is not already initialized
+func (b Backend) EnsureInit() error {
+	env, err := b.getEnv()
+	if err != nil {
+		return err
+	}
+	options := ExecuteOptions{Envs: env, Silent: true}
+
+	checkInitCmd := []string{"cat", "config"}
+	checkInitCmd = append(checkInitCmd, combineBackendOptions("cat", b)...)
+	_, _, err = ExecuteResticCommand(options, checkInitCmd...)
+
+	// Note that `restic` has a special exit code (10) to indicate that the
+	// repository does not exist. This exit code was introduced in `restic@0.17.0`
+	// on 2024-07-26. We're not using it here because this is a too recent and
+	// people on older versions of `restic` won't have this feature work  correctly.
+	// See: https://restic.readthedocs.io/en/latest/075_scripting.html#exit-codes
+	if err != nil {
 		colors.Body.Printf("Initializing backend \"%s\"...\n", b.name)
-		cmd := []string{"init"}
-		cmd = append(cmd, combineBackendOptions("init", b)...)
-		_, _, err := ExecuteResticCommand(options, cmd...)
+		initCmd := []string{"init"}
+		initCmd = append(initCmd, combineBackendOptions("init", b)...)
+		_, _, err := ExecuteResticCommand(options, initCmd...)
 		return err
 	}
+
+	return err
 }
 
 func (b Backend) Exec(args []string) error {

internal/backend_test.go

@@ -3,8 +3,10 @@ package internal
 import (
 	"fmt"
 	"os"
+	"path"
 	"testing"
 
+	"github.com/cupcakearmy/autorestic/internal/flags"
 	"github.com/spf13/viper"
 	"github.com/stretchr/testify/assert"
 )
@@ -263,3 +265,69 @@ func TestValidate(t *testing.T) {
 		assert.EqualError(t, err, "backend foo requires a key but none was provided")
 	})
 }
+
+func TestValidateInitsRepo(t *testing.T) {
+	// This is normally initialized by the cobra commands but they don't run in
+	// this test so we do it ourselves.
+	flags.RESTIC_BIN = "restic"
+
+	workDir := t.TempDir()
+
+	b := Backend{
+		name: "test",
+		Type: "local",
+		Path: path.Join(workDir, "backend"),
+		Key:  "supersecret",
+	}
+
+	config = &Config{Backends: map[string]Backend{"test": b}}
+	defer func() { config = nil }()
+
+	// Check should fail because the repo doesn't exist
+	err := b.Exec([]string{"check"})
+	assert.Error(t, err)
+
+	err = b.validate()
+	assert.NoError(t, err)
+
+	// Check should pass now
+	err = b.Exec([]string{"check"})
+	assert.NoError(t, err)
+}
+
+func TestEnsureInit(t *testing.T) {
+	// This is normally initialized by the cobra commands but they don't run in
+	// this test so we do it ourselves.
+	flags.RESTIC_BIN = "restic"
+
+	workDir := t.TempDir()
+
+	b := Backend{
+		name: "test",
+		Type: "local",
+		Path: path.Join(workDir, "backend"),
+		Key:  "supersecret",
+	}
+
+	config = &Config{Backends: map[string]Backend{"test": b}}
+	defer func() { config = nil }()
+
+	// Check should fail because the repo doesn't exist
+	err := b.Exec([]string{"check"})
+	assert.Error(t, err)
+
+	err = b.EnsureInit()
+	assert.NoError(t, err)
+
+	// Check should pass now
+	err = b.Exec([]string{"check"})
+	assert.NoError(t, err)
+
+	// Run again to make sure it's idempotent
+	err = b.EnsureInit()
+	assert.NoError(t, err)
+
+	// Check should still pass
+	err = b.Exec([]string{"check"})
+	assert.NoError(t, err)
+}

internal/location.go

@@ -222,6 +222,14 @@ func (l Location) Backup(cron bool, specificBackend string) []error {
 			continue
 		}
 
+		if backend.Init {
+			err = backend.EnsureInit()
+			if err != nil {
+				errors = append(errors, err)
+				continue
+			}
+		}
+
 		cmd := []string{"backup"}
 		cmd = append(cmd, combineAllOptions("backup", l, backend)...)
 		if cron {