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mirror of https://github.com/raseels-repos/golang-saas-starter-kit.git synced 2025-06-13 00:07:30 +02:00
2019-07-12 23:28:53 -08:00

272 lines
9.0 KiB
Go

package devops
import (
"io/ioutil"
"log"
"os"
"path/filepath"
"strings"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/secretsmanager"
"github.com/fsnotify/fsnotify"
"github.com/pkg/errors"
)
// SyncCfgInit provides the functionality to keep config files sync'd between running tasks and across deployments.
func SyncCfgInit(log *log.Logger, awsSession *session.Session, secretPrefix, watchDir string, syncInterval time.Duration) (func(), error) {
localfiles := make(map[string]time.Time)
// Do the initial sync before starting file watch to download any existing configs.
err := SyncCfgDir(log, awsSession, secretPrefix, watchDir, localfiles)
if err != nil {
return nil, err
}
// Create a new file watcher.
watcher, err := fsnotify.NewWatcher()
if err != nil {
return nil, errors.WithStack(err)
}
// Return function that will should be run in the back ground via a go routine that will watch for new files created
// locally and updated in AWS Secrets Manager.
f := func() {
defer watcher.Close()
// Init the watch to wait for sync local files to Secret Manager.
WatchCfgDir(log, awsSession, secretPrefix, watchDir, watcher, localfiles)
// Init ticker to sync remote files from Secret Manager locally at the defined interval.
if syncInterval.Seconds() > 0 {
ticker := time.NewTicker(syncInterval)
defer ticker.Stop()
go func() {
for _ = range ticker.C {
log.Println("AWS Secrets Manager : Checking for remote updates")
// Do the initial sync before starting file watch to download any existing configs.
err := SyncCfgDir(log, awsSession, secretPrefix, watchDir, localfiles)
if err != nil {
log.Printf("AWS Secrets Manager : Remote sync error - %+v", err)
}
}
}()
}
}
log.Printf("AWS Secrets Manager : Watching config dir %s", watchDir)
// Note: Out of the box fsnotify can watch a single file, or a single directory.
if err := watcher.Add(watchDir); err != nil {
return nil, errors.Wrapf(err, "failed to add file watcher to %s", watchDir)
}
return f, nil
}
// SyncCfgDir lists all the Secrets from AWS Secrets Manager for a provided prefix and downloads them locally.
func SyncCfgDir(log *log.Logger, awsSession *session.Session, secretPrefix, watchDir string, localfiles map[string]time.Time) error {
svc := secretsmanager.New(awsSession)
// Get a list of secrets for the prefix when the time they were last changed.
secretIDs := make(map[string]time.Time)
err := svc.ListSecretsPages(&secretsmanager.ListSecretsInput{}, func(res *secretsmanager.ListSecretsOutput, lastPage bool) bool {
for _, s := range res.SecretList {
// Skip any secret that does not have a matching prefix.
if !strings.HasPrefix(*s.Name, secretPrefix) {
continue
}
secretIDs[*s.Name] = s.LastChangedDate.UTC()
}
return !lastPage
})
if err != nil {
return errors.Wrap(err, "failed to list secrets")
}
for id, curChanged := range secretIDs {
// Load the secret by ID from Secrets Manager.
res, err := svc.GetSecretValue(&secretsmanager.GetSecretValueInput{
SecretId: aws.String(id),
})
if err != nil {
return errors.Wrapf(err, "failed to get secret value for id %s", id)
}
filename := filepath.Base(id)
localpath := filepath.Join(watchDir, filename)
// Ensure the secret exists locally.
if exists(localpath) {
// If the secret was previously downloaded and current last changed time is less than or equal to the time
// the secret was last downloaded, then no need to update.
if lastChanged, ok := localfiles[id]; ok && curChanged.UTC().Unix() <= lastChanged.UTC().Unix() {
continue
}
}
log.Printf("AWS Secrets Manager : Writing Config %s", filename)
err = ioutil.WriteFile(localpath, res.SecretBinary, 0644)
if err != nil {
return errors.Wrapf(err, "failed to write secret value for id %s to %s", id, localpath)
}
// Only mark that the secret was updated when the file was successfully saved locally.
localfiles[id] = curChanged
}
return nil
}
// WatchCfgDir watches for new/updated files locally and uploads them to in AWS Secrets Manager.
func WatchCfgDir(log *log.Logger, awsSession *session.Session, secretPrefix, dir string, watcher *fsnotify.Watcher, localfiles map[string]time.Time) error {
for {
select {
// watch for events
case event, ok := <-watcher.Events:
if !ok {
return nil
}
err := handleWatchCfgEvent(log, awsSession, secretPrefix, event)
if err != nil {
log.Printf("AWS Secrets Manager : Watcher Error - %+v", err)
}
// watch for errors
case err, ok := <-watcher.Errors:
if !ok {
return nil
}
if err != nil {
log.Printf("AWS Secrets Manager : Watcher Error - %+v", err)
}
}
}
return nil
}
// handleWatchCfgEvent handles a fsnotify event. For new files, secrets are created, for updated files, the secret is
// updated. For deleted files the secret is removed.
func handleWatchCfgEvent(log *log.Logger, awsSession *session.Session, secretPrefix string, event fsnotify.Event) error {
svc := secretsmanager.New(awsSession)
fname := filepath.Base(event.Name)
secretID := filepath.Join(secretPrefix, fname)
if event.Op&fsnotify.Create == fsnotify.Create || event.Op&fsnotify.Write == fsnotify.Write {
dat, err := ioutil.ReadFile(event.Name)
if err != nil {
return errors.Wrapf(err, "file watcher failed to read file %s", event.Name)
}
// Create the new entry in AWS Secret Manager for the file.
_, err = svc.CreateSecret(&secretsmanager.CreateSecretInput{
Name: aws.String(secretID),
SecretString: aws.String(string(dat)),
})
if err != nil {
if aerr, ok := err.(awserr.Error); !ok {
if aerr.Code() == secretsmanager.ErrCodeInvalidRequestException {
// InvalidRequestException: You can't create this secret because a secret with this
// name is already scheduled for deletion.
// Restore secret after it was already previously deleted.
_, err = svc.RestoreSecret(&secretsmanager.RestoreSecretInput{
SecretId: aws.String(secretID),
})
if err != nil {
return errors.Wrapf(err, "file watcher failed to restore secret %s for %s", secretID, event.Name)
}
} else if aerr.Code() != secretsmanager.ErrCodeResourceExistsException {
return errors.Wrapf(err, "file watcher failed to create secret %s for %s", secretID, event.Name)
}
}
// If where was a resource exists error for create, then need to update the secret instead.
_, err = svc.UpdateSecret(&secretsmanager.UpdateSecretInput{
SecretId: aws.String(secretID),
SecretString: aws.String(string(dat)),
})
if err != nil {
return errors.Wrapf(err, "file watcher failed to update secret %s for %s", secretID, event.Name)
}
log.Printf("AWS Secrets Manager : Secret %s updated for %s", secretID, event.Name)
} else {
log.Printf("AWS Secrets Manager : Secret %s created for %s", secretID, event.Name)
}
} else if event.Op&fsnotify.Remove == fsnotify.Remove || event.Op&fsnotify.Rename == fsnotify.Rename {
// Delay delete to ensure the file is really deleted.
//delCheck := time.NewTimer(time.Minute)
//<-delCheck.C
// Create the new entry in AWS Secret Manager for the file.
_, err := svc.DeleteSecret(&secretsmanager.DeleteSecretInput{
SecretId: aws.String(secretID),
// (Optional) Specifies that the secret is to be deleted without any recovery
// window. You can't use both this parameter and the RecoveryWindowInDays parameter
// in the same API call.
//
// An asynchronous background process performs the actual deletion, so there
// can be a short delay before the operation completes. If you write code to
// delete and then immediately recreate a secret with the same name, ensure
// that your code includes appropriate back off and retry logic.
//
// Use this parameter with caution. This parameter causes the operation to skip
// the normal waiting period before the permanent deletion that AWS would normally
// impose with the RecoveryWindowInDays parameter. If you delete a secret with
// the ForceDeleteWithouRecovery parameter, then you have no opportunity to
// recover the secret. It is permanently lost.
ForceDeleteWithoutRecovery: aws.Bool(false),
// (Optional) Specifies the number of days that Secrets Manager waits before
// it can delete the secret. You can't use both this parameter and the ForceDeleteWithoutRecovery
// parameter in the same API call.
//
// This value can range from 7 to 30 days.
RecoveryWindowInDays: aws.Int64(30),
})
if err != nil {
return errors.Wrapf(err, "file watcher failed to delete secret %s for %s", secretID, event.Name)
}
log.Printf("AWS Secrets Manager : Secret %s deleted for %s", secretID, event.Name)
}
return nil
}
// Exists reports whether the named file or directory exists.
func exists(name string) bool {
if _, err := os.Stat(name); err != nil {
if os.IsNotExist(err) {
return false
}
}
return true
}