Add option to crash autorestic when key is missing instead of generating a new key (#383)

* feat(backend): add requireKey option to backend

This option will prevent `autorestic` from generating a key and will
cause it to crash instead. This is intended for use cases where you want
to provision the key yourself and don't want `autorestic` to
accidentally generate one for you.

* doc(backend): document requireKey

docs/pages/backend/index.md

@@ -16,3 +16,25 @@ backends:
 ## Types
 
 We restic supports multiple types of backends. See the [full list](/backend/available) for details.
+
+## Avoid Generating Keys
+
+By default, `autorestic` will generate a key for every backend if none is defined. This is done by updating your config file with the key.
+
+In cases where you want to provide the key yourself, you can ensure that `autorestic` doesn't accidentally generate one for you by setting `requireKey: true`.
+
+Example:
+
+```yaml | .autorestic.yml
+version: 2
+
+backends:
+  foo:
+    type: local
+    path: /data/my/backups
+    # Alternatively, you can set the key through the `AUTORESTIC_FOO_RESTIC_PASSWORD` environment variable.
+    key: ... your key here ...
+    requireKey: true
+```
+
+With this setting, if a key is missing, `autorestic` will crash instead of generating a new key and updating your config file.

go.mod

@@ -11,9 +11,11 @@ require (
 	github.com/robfig/cron v1.2.0
 	github.com/spf13/cobra v1.4.0
 	github.com/spf13/viper v1.11.0
+	github.com/stretchr/testify v1.9.0
 )
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fsnotify/fsnotify v1.5.1 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
@@ -23,6 +25,7 @@ require (
 	github.com/mitchellh/mapstructure v1.4.3 // indirect
 	github.com/pelletier/go-toml v1.9.4 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.0-beta.8 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/afero v1.8.2 // indirect
 	github.com/spf13/cast v1.4.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
@@ -32,5 +35,5 @@ require (
 	golang.org/x/text v0.3.8 // indirect
 	gopkg.in/ini.v1 v1.66.4 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
-	gopkg.in/yaml.v3 v3.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -182,8 +182,9 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXf
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.7.1 h1:5TQK59W5E3v0r2duFAb7P95B6hEeOyEnHRa8MjYSMTY=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/subosito/gotenv v1.2.0 h1:Slr1R9HxAlEKefgq5jn9U+DnETlIUa6HfgEzj0g5d7s=
 github.com/subosito/gotenv v1.2.0/go.mod h1:N0PQaV/YGNqwC0u51sEeR/aUtSLEXKX9iv69rRypqCw=
 github.com/yuin/goldmark v1.1.25/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
@@ -487,8 +488,8 @@ gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0 h1:hjy8E9ON/egN1tAYqKb61G10WtihqetD4sz2H+8nIeA=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
-gopkg.in/yaml.v3 v3.0.0/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

internal/backend.go

@@ -22,6 +22,7 @@ type Backend struct {
 	Type       string            `mapstructure:"type,omitempty"`
 	Path       string            `mapstructure:"path,omitempty"`
 	Key        string            `mapstructure:"key,omitempty"`
+	RequireKey bool              `mapstructure:"requireKey,omitempty"`
 	Env        map[string]string `mapstructure:"env,omitempty"`
 	Rest       BackendRest       `mapstructure:"rest,omitempty"`
 	Options    Options           `mapstructure:"options,omitempty"`
@@ -104,6 +105,9 @@ func (b Backend) validate() error {
 		// Check if key is set in environment
 		env, _ := b.getEnv()
 		if _, found := env["RESTIC_PASSWORD"]; !found {
+			if b.RequireKey {
+				return fmt.Errorf("backend %s requires a key but none was provided", b.name)
+			}
 			// No key set in config file or env => generate random key and save file
 			key := generateRandomKey()
 			b.Key = key

internal/backend_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestGenerateRepo(t *testing.T) {
@@ -222,4 +223,16 @@ func TestValidate(t *testing.T) {
 		}
 		assertEqual(t, err.Error(), "Backend \"foo\" has no \"path\"")
 	})
+
+	t.Run("require key with no key", func(t *testing.T) {
+		b := Backend{
+			name:       "foo",
+			Type:       "local",
+			Path:       "~/foo/bar",
+			RequireKey: true,
+		}
+		err := b.validate()
+		fmt.Printf("error: %v\n", err)
+		assert.EqualError(t, err, "backend foo requires a key but none was provided")
+	})
 }