refactoring (config): separate config loading and saving

The idea is that we can now plug and play different logic for loading
and saving configuration data via a go generator built from plugins

server/common/config.go

@@ -5,18 +5,15 @@ import (
 	"fmt"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/user"
-	"path/filepath"
 	"strings"
 	"sync"
 )
 
 var (
-	Config     Configuration
-	configPath string = filepath.Join(GetCurrentDir(), CONFIG_PATH+"config.json")
+	Config Configuration
 )
 
 type Configuration struct {
@@ -54,7 +51,6 @@ type FormElement struct {
 func init() {
 	Config = NewConfiguration()
 	Config.Load()
-	Config.Save()
 	Config.Initialise()
 }
 
@@ -206,16 +202,9 @@ func (this *Form) Iterator() []FormIterator {
 }
 
 func (this *Configuration) Load() {
-	file, err := os.OpenFile(configPath, os.O_RDONLY, os.ModePerm)
+	cFile, err := LoadConfig()
 	if err != nil {
-		Log.Warning("Can't read from config file")
-		return
-	}
-	defer file.Close()
-
-	cFile, err := ioutil.ReadAll(file)
-	if err != nil {
-		Log.Warning("Can't parse config file")
+		Log.Error("config::load %s", err)
 		return
 	}
 
@@ -283,13 +272,17 @@ func (this *Configuration) Debug() *FormElement {
 }
 
 func (this *Configuration) Initialise() {
+	shouldSave := false
 	if env := os.Getenv("ADMIN_PASSWORD"); env != "" {
+		shouldSave = true
 		this.Get("auth.admin").Set(env)
 	}
 	if env := os.Getenv("APPLICATION_URL"); env != "" {
+		shouldSave = true
 		this.Get("general.host").Set(env).String()
 	}
 	if this.Get("general.secret_key").String() == "" {
+		shouldSave = true
 		key := RandomString(16)
 		this.Get("general.secret_key").Set(key)
 	}
@@ -325,6 +318,9 @@ func (this *Configuration) Initialise() {
 				"label": "Drive",
 			},
 		}
+		shouldSave = true
+	}
+	if shouldSave {
 		this.Save()
 	}
 	InitSecretDerivate(this.Get("general.secret_key").String())
@@ -342,14 +338,9 @@ func (this Configuration) Save() Configuration {
 	})
 	v, _ = sjson.Set(v, "connections", this.Conn)
 
-	// deploy the config in our config.json
-	file, err := os.Create(configPath)
-	if err != nil {
-		Log.Error("Filestash needs to be able to create/edit its own configuration which it can't at the moment. Change the permission for filestash to create and edit `%s`", configPath)
-		return this
+	if err := SaveConfig(PrettyPrint([]byte(v))); err != nil {
+		Log.Error("config::save %s", err.Error())
 	}
-	defer file.Close()
-	file.Write(PrettyPrint([]byte(v)))
 	return this
 }
 

server/common/config_state.go

@@ -0,0 +1,51 @@
+package common
+
+/*
+ * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNI
+ * WARNING - CHANGE IN THIS FILE CAN SILENTLY BREAK OTHER INSTALLATION - WARNING
+ * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARN
+ *
+ * Some contributors wanted to be able to load and persist config in other system
+ * like S3 and provide custom encryption layer on top of it. Those contributors have
+ * custom plugins which run generators that override this file before the build is
+ * generated. Indeed for that specific use case we couldn't extend the runtime plugin
+ * mechanism so had to fallback to this approach which would set the config loader at
+ * build time, hence this warning.
+ */
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+var (
+	configPath string = filepath.Join(GetCurrentDir(), CONFIG_PATH+"config.json")
+)
+
+func LoadConfig() ([]byte, error) {
+	file, err := os.OpenFile(configPath, os.O_RDONLY, os.ModePerm)
+	if err != nil {
+		return nil, err
+	}
+	cFile, err := ioutil.ReadAll(file)
+	file.Close()
+	if err != nil {
+		return nil, err
+	}
+	return cFile, nil
+}
+
+func SaveConfig(v []byte) error {
+	file, err := os.Create(configPath)
+	if err != nil {
+		return fmt.Errorf(
+			"Filestash needs to be able to create/edit its own configuration which it can't at the moment. "+
+				"Change the permission for filestash to create and edit `%s`",
+			configPath,
+		)
+	}
+	file.Write(PrettyPrint([]byte(v)))
+	return file.Close()
+}

server/ctrl/config.go

@@ -53,18 +53,10 @@ func PrivateConfigHandler(ctx App, res http.ResponseWriter, req *http.Request) {
 
 func PrivateConfigUpdateHandler(ctx App, res http.ResponseWriter, req *http.Request) {
 	b, _ := ioutil.ReadAll(req.Body)
-	b = PrettyPrint(b)
-	file, err := os.Create(configpath)
-	if err != nil {
+	if err := SaveConfig(b); err != nil {
 		SendErrorResult(res, err)
 		return
 	}
-	defer file.Close()
-	if _, err := file.Write(b); err != nil {
-		SendErrorResult(res, err)
-		return
-	}
-	file.Close()
 	Config.Load()
 	SendSuccessResult(res, nil)
 }