Move config upgrade to separate upgrade.go

app.go

@@ -114,6 +114,12 @@ func main() {
 			log.Fatal(err)
 		}
 
+		// Do the upgrade if necessary
+		err = upgradeConfig()
+		if err != nil {
+			log.Fatal(err)
+		}
+
 		// parse from config file
 		err = parseConfig()
 		if err != nil {
@@ -134,14 +140,8 @@ func main() {
 		os.Args = os.Args[:1]
 	}
 
-	// Do the upgrade if necessary
-	err := upgradeConfig()
-	if err != nil {
-		log.Fatal(err)
-	}
-
 	// Save the updated config
-	err = writeConfig()
+	err := writeConfig()
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -260,77 +260,3 @@ func askUsernamePasswordIfPossible() error {
 	config.AuthPass = password
 	return nil
 }
-
-// Performs necessary upgrade operations if needed
-func upgradeConfig() error {
-	if config.SchemaVersion == SchemaVersion {
-		// No upgrade, do nothing
-		return nil
-	}
-
-	if config.SchemaVersion > SchemaVersion {
-		// Unexpected -- the config file is newer than we expect
-		return fmt.Errorf("configuration file is supposed to be used with a newer version of AdGuard Home, schema=%d", config.SchemaVersion)
-	}
-
-	// Perform upgrade operations for each consecutive version upgrade
-	for oldVersion, newVersion := config.SchemaVersion, config.SchemaVersion+1; newVersion <= SchemaVersion; {
-		err := upgradeConfigSchema(oldVersion, newVersion)
-		if err != nil {
-			log.Fatal(err)
-		}
-
-		// Increment old and new versions
-		oldVersion++
-		newVersion++
-	}
-
-	// Save the current schema version
-	config.SchemaVersion = SchemaVersion
-
-	return nil
-}
-
-// Upgrade from oldVersion to newVersion
-func upgradeConfigSchema(oldVersion int, newVersion int) error {
-	if oldVersion == 0 && newVersion == 1 {
-		log.Printf("Updating schema from %d to %d", oldVersion, newVersion)
-
-		// The first schema upgrade:
-		// Added "ID" field to "filter" -- we need to populate this field now
-		// Added "config.ourDataDir" -- where we will now store filters contents
-		for i := range config.Filters {
-			filter := &config.Filters[i] // otherwise we will be operating on a copy
-
-			// Set the filter ID
-			log.Printf("Seting ID=%d for filter %s", NextFilterId, filter.URL)
-			filter.ID = NextFilterId
-			NextFilterId++
-
-			// Forcibly update the filter
-			_, err := filter.update(true)
-			if err != nil {
-				log.Fatal(err)
-			}
-
-			// Saving it to the filters dir now
-			err = filter.save()
-			if err != nil {
-				log.Fatal(err)
-			}
-		}
-
-		// No more "dnsfilter.txt", filters are now loaded from config.ourDataDir/filters/
-		dnsFilterPath := filepath.Join(config.ourBinaryDir, "dnsfilter.txt")
-		_, err := os.Stat(dnsFilterPath)
-		if !os.IsNotExist(err) {
-			log.Printf("Deleting %s as we don't need it anymore", dnsFilterPath)
-			err = os.Remove(dnsFilterPath)
-			if err != nil {
-				log.Printf("Cannot remove %s due to %s", dnsFilterPath, err)
-			}
-		}
-	}
-
-	return nil
-}

config.go

@@ -16,7 +16,7 @@ import (
 
 // Current schema version. We compare it with the value from
 // the configuration file and perform necessary upgrade operations if needed
-const SchemaVersion = 1
+const CurrentSchemaVersion = 1
 
 // Directory where we'll store all downloaded filters contents
 const FiltersDir = "filters"
@@ -188,7 +188,7 @@ func writeConfig() error {
 		log.Printf("Couldn't generate YAML file: %s", err)
 		return err
 	}
-	err = writeFileSafe(configFile, yamlText)
+	err = safeWriteFile(configFile, yamlText)
 	if err != nil {
 		log.Printf("Couldn't save YAML config: %s", err)
 		return err
@@ -215,7 +215,7 @@ func writeCoreDNSConfig() error {
 		log.Printf("Couldn't generate DNS config: %s", err)
 		return err
 	}
-	err = writeFileSafe(coreFile, []byte(configText))
+	err = safeWriteFile(coreFile, []byte(configText))
 	if err != nil {
 		log.Printf("Couldn't save DNS config: %s", err)
 		return err

control.go

@@ -664,7 +664,7 @@ func (filter *filter) save() error {
 	filterFilePath := filter.Path()
 	log.Printf("Saving filter %d contents to: %s", filter.ID, filterFilePath)
 
-	err := writeFileSafe(filterFilePath, filter.Contents)
+	err := safeWriteFile(filterFilePath, filter.Contents)
 	if err != nil {
 		return err
 	}

helpers.go

@@ -19,7 +19,7 @@ import (
 // ----------------------------------
 
 // Writes data first to a temporary file and then renames it to what's specified in path
-func writeFileSafe(path string, data []byte) error {
+func safeWriteFile(path string, data []byte) error {
 	dir := filepath.Dir(path)
 	err := os.MkdirAll(dir, 0755)
 	if err != nil {

upgrade.go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+
+	"gopkg.in/yaml.v2"
+)
+
+// Performs necessary upgrade operations if needed
+func upgradeConfig() error {
+	// read a config file into an interface map, so we can manipulate values without losing any
+	configFile := filepath.Join(config.ourBinaryDir, config.ourConfigFilename)
+	if _, err := os.Stat(configFile); os.IsNotExist(err) {
+		log.Printf("config file %s does not exist, nothing to upgrade", configFile)
+		return nil
+	}
+	diskConfig := map[string]interface{}{}
+	body, err := ioutil.ReadFile(configFile)
+	if err != nil {
+		log.Printf("Couldn't read config file '%s': %s", configFile, err)
+		return err
+	}
+
+	err = yaml.Unmarshal(body, &diskConfig)
+	if err != nil {
+		log.Printf("Couldn't parse config file '%s': %s", configFile, err)
+		return err
+	}
+
+	schemaVersionInterface, ok := diskConfig["schema_version"]
+	trace("schemaVersionInterface = %v, ok = %v", schemaVersionInterface, ok)
+	if !ok {
+		// no schema version, set it to 0
+		schemaVersionInterface = 0
+	}
+
+	schemaVersion, ok := schemaVersionInterface.(int)
+	if !ok {
+		err = fmt.Errorf("configuration file contains non-integer schema_version, abort")
+		log.Println(err)
+		return err
+	}
+
+	if schemaVersion == CurrentSchemaVersion {
+		// do nothing
+		return nil
+	}
+
+	return upgradeConfigSchema(schemaVersion, &diskConfig)
+}
+
+// Upgrade from oldVersion to newVersion
+func upgradeConfigSchema(oldVersion int, diskConfig *map[string]interface{}) error {
+	switch oldVersion {
+	case 0:
+		err := upgradeSchema0to1(diskConfig)
+		if err != nil {
+			return err
+		}
+	default:
+		err := fmt.Errorf("configuration file contains unknown schema_version, abort")
+		log.Println(err)
+		return err
+	}
+
+	configFile := filepath.Join(config.ourBinaryDir, config.ourConfigFilename)
+	body, err := yaml.Marshal(diskConfig)
+	if err != nil {
+		log.Printf("Couldn't generate YAML file: %s", err)
+		return err
+	}
+
+	err = safeWriteFile(configFile, body)
+	if err != nil {
+		log.Printf("Couldn't save YAML config: %s", err)
+		return err
+	}
+
+	return nil
+}
+
+func upgradeSchema0to1(diskConfig *map[string]interface{}) error {
+	trace("Called")
+
+	// The first schema upgrade:
+	// Added "ID" field to "filter" -- we need to populate this field now
+	// Added "config.ourDataDir" -- where we will now store filters contents
+	for i := range config.Filters {
+		filter := &config.Filters[i] // otherwise we will be operating on a copy
+
+		// Set the filter ID
+		log.Printf("Seting ID=%d for filter %s", NextFilterId, filter.URL)
+		filter.ID = NextFilterId
+		NextFilterId++
+
+		// Forcibly update the filter
+		_, err := filter.update(true)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		// Saving it to the filters dir now
+		err = filter.save()
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	// No more "dnsfilter.txt", filters are now loaded from config.ourDataDir/filters/
+	dnsFilterPath := filepath.Join(config.ourBinaryDir, "dnsfilter.txt")
+	_, err := os.Stat(dnsFilterPath)
+	if !os.IsNotExist(err) {
+		log.Printf("Deleting %s as we don't need it anymore", dnsFilterPath)
+		err = os.Remove(dnsFilterPath)
+		if err != nil {
+			log.Printf("Cannot remove %s due to %s", dnsFilterPath, err)
+			// not fatal, move on
+		}
+	}
+
+	(*diskConfig)["schema_version"] = 1
+
+	return nil
+}