compose/ecs/secrets/init.go

package secrets

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
)

type Secret struct {
	Name string
	Keys []string
}

func CreateSecretFiles(secret Secret, path string) error {
	value, ok := os.LookupEnv(secret.Name)
	if !ok {
		return fmt.Errorf("%q variable not set", secret.Name)
	}

	secrets := filepath.Join(path, secret.Name)

	if len(secret.Keys) == 0 {
		// raw Secret
		fmt.Printf("inject Secret %q info %s\n", secret.Name, secrets)
		return ioutil.WriteFile(secrets, []byte(value), 0444)
	}

	var unmarshalled interface{}
	err := json.Unmarshal([]byte(value), &unmarshalled)
	if err != nil {
		return fmt.Errorf("%q Secret is not a valid JSON document: %w", secret.Name, err)
	}

	dict, ok := unmarshalled.(map[string]interface{})
	if !ok {
		return fmt.Errorf("%q Secret is not a JSON dictionary: %w", secret.Name, err)
	}
	err = os.MkdirAll(secrets, 0755)
	if err != nil {
		return err
	}

	if contains(secret.Keys, "*") {
		var keys []string
		for k := range dict {
			keys = append(keys, k)
		}
		secret.Keys = keys
	}

	for _, k := range secret.Keys {
		path := filepath.Join(secrets, k)
		fmt.Printf("inject Secret %q info %s\n", k, path)

		v, ok := dict[k]
		if !ok {
			return fmt.Errorf("%q Secret has no %q key", secret.Name, k)
		}

		var raw []byte
		if s, ok := v.(string); ok {
			raw = []byte(s)
		} else {
			raw, err = json.Marshal(v)
			if err != nil {
				return err
			}
		}

		err = ioutil.WriteFile(path, raw, 0444)
		if err != nil {
			return err
		}
	}
	return nil
}

func contains(keys []string, s string) bool {
	for _, k := range keys {
		if k == s {
			return true
		}
	}
	return false
}