add mergeYaml

Author: kamushadenes

Dockerfile

@@ -1,7 +1,11 @@
-FROM scratch
+FROM busybox:glibc
 
 COPY docker-sync /
+COPY entrypoint.sh /
+
+RUN chmod +x /docker-sync
+RUN chmod +x /entrypoint.sh
 
 EXPOSE 9090
 
-ENTRYPOINT ["/docker-sync"]
+ENTRYPOINT ["/entrypoint.sh"]

cmd/dockersync/cmd/mergeYaml.go

@@ -0,0 +1,89 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/spf13/cobra"
+	"gopkg.in/yaml.v3"
+)
+
+var yamlFiles []string
+
+// mergeYamlCmd represents the mergeYaml command
+var mergeYamlCmd = &cobra.Command{
+	Use:   "mergeYaml",
+	Short: "Merge two yaml files",
+	PreRun: func(cmd *cobra.Command, args []string) {
+		cmd.Annotations = make(map[string]string)
+		cmd.Annotations["error"] = ""
+	},
+	Run: func(cmd *cobra.Command, args []string) {
+		outFile := cmd.Flag("output").Value.String()
+
+		base := make(map[string]interface{})
+		currentMap := make(map[string]interface{})
+
+		for _, fname := range yamlFiles {
+			data, err := os.ReadFile(fname)
+			if err != nil {
+				cmd.Annotations["error"] = err.Error()
+				return
+			}
+			if err := yaml.Unmarshal(data, &currentMap); err != nil {
+				cmd.Annotations["error"] = err.Error()
+				return
+			}
+			base = mergeMaps(base, currentMap)
+		}
+
+		config, err := yaml.Marshal(base)
+		if err != nil {
+			cmd.Annotations["error"] = err.Error()
+			return
+		}
+
+		if outFile == "" {
+			fmt.Println(string(config))
+		} else {
+			if err := os.WriteFile(outFile, config, 0644); err != nil {
+				cmd.Annotations["error"] = err.Error()
+				return
+			}
+		}
+	},
+	PostRun: func(cmd *cobra.Command, args []string) {
+		// Wait for a second to allow for any pending log messages to be flushed
+		time.Sleep(1 * time.Second)
+		if cmd.Annotations["error"] != "" {
+			os.Exit(1)
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(mergeYamlCmd)
+
+	mergeYamlCmd.Flags().StringP("output", "o", "", "File to write config to (default is stdout)")
+	mergeYamlCmd.Flags().StringSliceVarP(&yamlFiles, "yamlFiles", "f", []string{}, "Yaml files to merge")
+}
+
+func mergeMaps(a, b map[string]interface{}) map[string]interface{} {
+	out := make(map[string]interface{}, len(a))
+	for k, v := range a {
+		out[k] = v
+	}
+	for k, v := range b {
+		if v, ok := v.(map[string]interface{}); ok {
+			if bv, ok := out[k]; ok {
+				if bv, ok := bv.(map[string]interface{}); ok {
+					out[k] = mergeMaps(bv, v)
+					continue
+				}
+			}
+		}
+		out[k] = v
+	}
+	return out
+}

cmd/dockersync/cmd/writeConfig.go

@@ -16,7 +16,6 @@ var writeConfigCmd = &cobra.Command{
 		outFile := cmd.Flag("output").Value.String()
 
 		if outFile == "" {
-
 			settings := viper.AllSettings()
 			yamlSettings, err := yaml.Marshal(settings)
 			if err != nil {

entrypoint.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+# check if /config.yaml exists
+if [ ! -f /config.yaml ]; then
+  /docker-sync mergeYaml -o /config.yaml -f /config_map.yaml -f /secret.yaml
+fi
+
+/docker-sync "$@"