Make environment-to-ini support loading key value from file (#24832)

Replace #19857

Close #19856
Close #10311
Close #10123

Major changes:

1. Move a lot of code from `environment-to-ini.go` to `config_env.go` to
make them testable.
2. Add `__FILE` support
3. Update documents
4. Add tests

contrib/environment-to-ini/environment-to-ini.go

@@ -5,8 +5,6 @@ package main
 
 import (
 	"os"
-	"regexp"
-	"strconv"
 	"strings"
 
 	"code.gitea.io/gitea/modules/log"
@@ -14,7 +12,7 @@ import (
 	"code.gitea.io/gitea/modules/util"
 
 	"github.com/urfave/cli"
-	ini "gopkg.in/ini.v1"
+	"gopkg.in/ini.v1"
 )
 
 // EnvironmentPrefix environment variables prefixed with this represent ini values to write
@@ -32,6 +30,10 @@ func main() {
 	will be mapped to the ini section "[section_name]" and the key
 	"KEY_NAME" with the value as provided.
 
+	Environment variables of the form "GITEA__SECTION_NAME__KEY_NAME__FILE"
+	will be mapped to the ini section "[section_name]" and the key
+	"KEY_NAME" with the value loaded from the specified file.
+
 	Environment variables are usually restricted to a reduced character
 	set "0-9A-Z_" - in order to allow the setting of sections with
 	characters outside of that set, they should be escaped as following:
@@ -96,11 +98,11 @@ func runEnvironmentToIni(c *cli.Context) error {
 	setting.SetCustomPathAndConf(providedCustom, providedConf, providedWorkPath)
 
 	cfg := ini.Empty()
-	isFile, err := util.IsFile(setting.CustomConf)
+	confFileExists, err := util.IsFile(setting.CustomConf)
 	if err != nil {
 		log.Fatal("Unable to check if %s is a file. Error: %v", setting.CustomConf, err)
 	}
-	if isFile {
+	if confFileExists {
 		if err := cfg.Append(setting.CustomConf); err != nil {
 			log.Fatal("Failed to load custom conf '%s': %v", setting.CustomConf, err)
 		}
@@ -109,47 +111,11 @@ func runEnvironmentToIni(c *cli.Context) error {
 	}
 	cfg.NameMapper = ini.SnackCase
 
-	changed := false
+	prefixGitea := c.String("prefix") + "__"
+	suffixFile := "__FILE"
+	changed := setting.EnvironmentToConfig(cfg, prefixGitea, suffixFile, os.Environ())
 
-	prefix := c.String("prefix") + "__"
-
-	for _, kv := range os.Environ() {
-		idx := strings.IndexByte(kv, '=')
-		if idx < 0 {
-			continue
-		}
-		eKey := kv[:idx]
-		value := kv[idx+1:]
-		if !strings.HasPrefix(eKey, prefix) {
-			continue
-		}
-		eKey = eKey[len(prefix):]
-		sectionName, keyName := DecodeSectionKey(eKey)
-		if len(keyName) == 0 {
-			continue
-		}
-		section, err := cfg.GetSection(sectionName)
-		if err != nil {
-			section, err = cfg.NewSection(sectionName)
-			if err != nil {
-				log.Error("Error creating section: %s : %v", sectionName, err)
-				continue
-			}
-		}
-		key := section.Key(keyName)
-		if key == nil {
-			key, err = section.NewKey(keyName, value)
-			if err != nil {
-				log.Error("Error creating key: %s in section: %s with value: %s : %v", keyName, sectionName, value, err)
-				continue
-			}
-		}
-		oldValue := key.Value()
-		if !changed && oldValue != value {
-			changed = true
-		}
-		key.SetValue(value)
-	}
+	// try to save the config file
 	destination := c.String("out")
 	if len(destination) == 0 {
 		destination = setting.CustomConf
@@ -161,6 +127,8 @@ func runEnvironmentToIni(c *cli.Context) error {
 			return err
 		}
 	}
+
+	// clear Gitea's specific environment variables if requested
 	if c.Bool("clear") {
 		for _, kv := range os.Environ() {
 			idx := strings.IndexByte(kv, '=')
@@ -168,69 +136,11 @@ func runEnvironmentToIni(c *cli.Context) error {
 				continue
 			}
 			eKey := kv[:idx]
-			if strings.HasPrefix(eKey, prefix) {
+			if strings.HasPrefix(eKey, prefixGitea) {
 				_ = os.Unsetenv(eKey)
 			}
 		}
 	}
+
 	return nil
 }
-
-const escapeRegexpString = "_0[xX](([0-9a-fA-F][0-9a-fA-F])+)_"
-
-var escapeRegex = regexp.MustCompile(escapeRegexpString)
-
-// DecodeSectionKey will decode a portable string encoded Section__Key pair
-// Portable strings are considered to be of the form [A-Z0-9_]*
-// We will encode a disallowed value as the UTF8 byte string preceded by _0X and
-// followed by _. E.g. _0X2C_ for a '-' and _0X2E_ for '.'
-// Section and Key are separated by a plain '__'.
-// The entire section can be encoded as a UTF8 byte string
-func DecodeSectionKey(encoded string) (string, string) {
-	section := ""
-	key := ""
-
-	inKey := false
-	last := 0
-	escapeStringIndices := escapeRegex.FindAllStringIndex(encoded, -1)
-	for _, unescapeIdx := range escapeStringIndices {
-		preceding := encoded[last:unescapeIdx[0]]
-		if !inKey {
-			if splitter := strings.Index(preceding, "__"); splitter > -1 {
-				section += preceding[:splitter]
-				inKey = true
-				key += preceding[splitter+2:]
-			} else {
-				section += preceding
-			}
-		} else {
-			key += preceding
-		}
-		toDecode := encoded[unescapeIdx[0]+3 : unescapeIdx[1]-1]
-		decodedBytes := make([]byte, len(toDecode)/2)
-		for i := 0; i < len(toDecode)/2; i++ {
-			// Can ignore error here as we know these should be hexadecimal from the regexp
-			byteInt, _ := strconv.ParseInt(toDecode[2*i:2*i+2], 16, 0)
-			decodedBytes[i] = byte(byteInt)
-		}
-		if inKey {
-			key += string(decodedBytes)
-		} else {
-			section += string(decodedBytes)
-		}
-		last = unescapeIdx[1]
-	}
-	remaining := encoded[last:]
-	if !inKey {
-		if splitter := strings.Index(remaining, "__"); splitter > -1 {
-			section += remaining[:splitter]
-			key += remaining[splitter+2:]
-		} else {
-			section += remaining
-		}
-	} else {
-		key += remaining
-	}
-	section = strings.ToLower(section)
-	return section, key
-}