[#3896bk] Configure base support for properties file parsing

parser/parser.go

@@ -0,0 +1,98 @@
+package parser
+
+import (
+	"fmt"
+	"github.com/buger/jsonparser"
+	"github.com/magiconair/properties"
+	"github.com/pkg/errors"
+	"go.uber.org/zap"
+	"os"
+)
+
+type ConfigurationParser string
+
+// The file parsing options that are available for a server configuration file.
+const (
+	File       = "file"
+	Yaml       = "yaml"
+	Properties = "properties"
+	Ini        = "ini"
+	Json       = "json"
+	Xml        = "xml"
+)
+
+// Defines a configuration file for the server startup. These will be looped over
+// and modified before the server finishes booting.
+type ConfigurationFile struct {
+	FileName string                         `json:"file"`
+	Parser   ConfigurationParser            `json:"parser"`
+	Replace  []ConfigurationFileReplacement `json:"replace"`
+}
+
+// Defines a single find/replace instance for a given server configuration file.
+type ConfigurationFileReplacement struct {
+	Match     string               `json:"match"`
+	Value     string               `json:"value"`
+	ValueType jsonparser.ValueType `json:"-"`
+}
+
+func (cfr *ConfigurationFileReplacement) UnmarshalJSON(data []byte) error {
+	if m, err := jsonparser.GetString(data, "match"); err != nil {
+		return err
+	} else {
+		cfr.Match = m
+	}
+
+	if v, dt, _, err := jsonparser.Get(data, "value"); err != nil {
+		return err
+	} else {
+		if dt != jsonparser.String && dt != jsonparser.Number && dt != jsonparser.Boolean {
+			return errors.New(
+				fmt.Sprintf("cannot parse JSON: received unexpected replacement value type: %d", dt),
+			)
+		}
+
+		cfr.Value = string(v)
+		cfr.ValueType = dt
+	}
+
+	return nil
+}
+
+// Parses a given configuration file and updates all of the values within as defined
+// in the API response from the Panel.
+func (f *ConfigurationFile) Parse(path string) error {
+	zap.S().Debugw("parsing configuration file", zap.String("path", path), zap.String("parser", string(f.Parser)))
+
+	switch f.Parser {
+	case Properties:
+		f.parsePropertiesFile(path)
+		break
+	}
+
+	return nil
+}
+
+// Parses a properties file and updates the values within it to match those that
+// are passed. Writes the file once completed.
+func (f *ConfigurationFile) parsePropertiesFile(path string) error {
+	p, err := properties.LoadFile(path, properties.UTF8)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	for _, replace := range f.Replace {
+		if _, _, err := p.Set(replace.Match, replace.Value); err != nil {
+			return errors.WithStack(err)
+		}
+	}
+
+	w, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0644);
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	_, err = p.Write(w, properties.UTF8)
+
+	return err
+}