Open Source Monorail

appengine/monorail/services/secrets_svc.py

+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is govered by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""A set of functions that provide persistence for secret keys.
+
+These keys are used in generating XSRF tokens, calling the CAPTCHA API,
+and validating that inbound emails are replies to notifications that
+we sent.
+
+Unlike other data stored in Monorail, this is kept in the GAE
+datastore rather than SQL because (1) it never needs to be used in
+combination with other SQL data, and (2) we may want to replicate
+issue content for various off-line reporting functionality, but we
+will never want to do that with these keys.  A copy is also kept in
+memcache for faster access.
+
+When no secrets are found, a new Secrets entity is created and initialized
+with randomly generated values for XSRF and email keys.
+
+If these secret values ever need to change:
+(1) Make the change on the Google Cloud Console in the Cloud Datastore tab.
+(2) Flush memcache.
+"""
+
+import logging
+
+from google.appengine.api import memcache
+from google.appengine.ext import ndb
+
+import settings
+from framework import framework_helpers
+
+
+GLOBAL_KEY = 'secrets_singleton_key'
+
+
+class Secrets(ndb.Model):
+  """Model for representing secret keys."""
+  # Keys we use to generate tokens.
+  xsrf_key = ndb.StringProperty(required=True)
+  email_key = ndb.StringProperty(required=True)
+
+  # Keys for other APIs that we use.
+  recaptcha_public_key = ndb.StringProperty()
+  recaptcha_private_key = ndb.StringProperty()
+
+  
+def MakeSecrets():
+  """Make a new Secrets model with random values for keys."""
+  secrets = Secrets(id=GLOBAL_KEY)
+  secrets.xsrf_key = framework_helpers.MakeRandomKey()
+  secrets.email_key = framework_helpers.MakeRandomKey()
+  # Note that recaptcha keys are not generated.  An admin
+  # will need to set them via the Google Cloud Console.
+  return secrets
+
+
+def GetSecrets():
+  """Get secret keys from memcache or datastore. Or, make new ones."""
+  secrets = memcache.get(GLOBAL_KEY)
+  if secrets:
+    return secrets
+
+  secrets = Secrets.get_by_id(GLOBAL_KEY)
+  if not secrets:
+    secrets = MakeSecrets()
+    secrets.put()
+
+  memcache.set(GLOBAL_KEY, secrets)
+  return secrets
+
+
+def GetXSRFKey():
+  """Return a secret key string used to generate XSRF tokens."""
+  return GetSecrets().xsrf_key
+
+
+def GetEmailKey():
+  """Return a secret key string used to generate email tokens."""
+  return GetSecrets().email_key
+
+
+def GetRecaptchaPublicKey():
+  """Return our public API key for reCAPTCHA."""
+  if settings.dev_mode:
+    return '6LebzNMSAAAAAMY8b_FaZvp8wymUO5Jsa0pIX7HO'
+
+  result = GetSecrets().recaptcha_public_key
+  if not result:
+    logging.warn('No recaptcha_public_key set.  Get one at recaptcha.net.')
+    logging.warn('Store it in Cloud Datastore via the Google Cloud Console.')
+
+  return result
+
+
+def GetRecaptchaPrivateKey():
+  """Return our private API key for reCAPTCHA."""
+  if settings.dev_mode:
+    return '6LebzNMSAAAAAHNVNiP2I7aNMv2AmxY5nReE2LZ4'
+
+  result = GetSecrets().recaptcha_private_key
+  if not result:
+    logging.warn('No recaptcha_private_key set.  Get one at recaptcha.net.')
+    logging.warn('Store it in Cloud Datastore via the Google Cloud Console.')
+
+  return result
+
+