Basic labels support

Adds basic labels support to the registry code (V2), and the API. Note that this does not yet add any UI related support.

util/config/superusermanager.py

@@ -1,5 +1,5 @@
 from multiprocessing.sharedctypes import Array
-from util.validation import MAX_LENGTH
+from util.validation import MAX_USERNAME_LENGTH
 
 class SuperUserManager(object):
   """ In-memory helper class for quickly accessing (and updating) the valid
@@ -11,7 +11,7 @@ class SuperUserManager(object):
     usernames = app.config.get('SUPER_USERS', [])
     usernames_str = ','.join(usernames)
 
-    self._max_length = len(usernames_str) + MAX_LENGTH + 1
+    self._max_length = len(usernames_str) + MAX_USERNAME_LENGTH + 1
     self._array = Array('c', self._max_length, lock=True)
     self._array.value = usernames_str
 

util/label_validator.py

@@ -0,0 +1,20 @@
+class LabelValidator(object):
+  """ Helper class for validating that labels meet prefix requirements. """
+  def __init__(self, app):
+    self.app = app
+
+    overridden_prefixes = app.config.get('LABEL_KEY_RESERVED_PREFIXES', [])
+    for prefix in overridden_prefixes:
+      if not prefix.endswith('.'):
+        raise Exception('Prefix "%s" in LABEL_KEY_RESERVED_PREFIXES must end in a dot', prefix)
+
+    default_prefixes = app.config.get('DEFAULT_LABEL_KEY_RESERVED_PREFIXES', [])
+    self.reserved_prefixed_set = set(default_prefixes + overridden_prefixes)
+
+  def has_reserved_prefix(self, label_key):
+    """ Validates that the provided label key does not match any reserved prefixes. """
+    for prefix in self.reserved_prefixed_set:
+      if label_key.startswith(prefix):
+        return True
+
+    return False

util/migrate/__init__.py

@@ -1,7 +1,7 @@
 import logging
 
-from sqlalchemy.types import TypeDecorator, Text
-from sqlalchemy.dialects.mysql import TEXT as MySQLText, LONGTEXT
+from sqlalchemy.types import TypeDecorator, Text, String
+from sqlalchemy.dialects.mysql import TEXT as MySQLText, LONGTEXT, VARCHAR as MySQLString
 
 
 logger = logging.getLogger(__name__)
@@ -20,3 +20,19 @@ class UTF8LongText(TypeDecorator):
       return dialect.type_descriptor(LONGTEXT(charset='utf8mb4', collation='utf8mb4_unicode_ci'))
     else:
       return dialect.type_descriptor(Text())
+
+
+class UTF8CharField(TypeDecorator):
+  """ Platform-independent UTF-8 Char type.
+
+  Uses MySQL's VARCHAR with charset utf8mb4, otherwise uses String, because
+  other engines default to UTF-8.
+  """
+  impl = String
+
+  def load_dialect_impl(self, dialect):
+    if dialect.name == 'mysql':
+      return dialect.type_descriptor(MySQLString(charset='utf8mb4', collation='utf8mb4_unicode_ci',
+                                                 length=self.impl.length))
+    else:
+      return dialect.type_descriptor(String(length=self.impl.length))

util/validation.py

@@ -1,5 +1,6 @@
 import string
 import re
+import json
 
 import anunidecode # Don't listen to pylint's lies. This import is required.
 
@@ -9,14 +10,21 @@ INVALID_PASSWORD_MESSAGE = 'Invalid password, password must be at least ' + \
 INVALID_USERNAME_CHARACTERS = r'[^a-z0-9_]'
 VALID_CHARACTERS = string.digits + string.lowercase
 
-MIN_LENGTH = 4
-MAX_LENGTH = 30
+MIN_USERNAME_LENGTH = 4
+MAX_USERNAME_LENGTH = 30
+
+VALID_LABEL_KEY_REGEX = r'^[a-z0-9](([a-z0-9]|[-.](?![.-]))*[a-z0-9])?$'
+
+
+def validate_label_key(label_key):
+  if len(label_key) > 255:
+    return False
+
+  return bool(re.match(VALID_LABEL_KEY_REGEX, label_key))
 
 
 def validate_email(email_address):
-  if re.match(r'[^@]+@[^@]+\.[^@]+', email_address):
-    return True
-  return False
+  return bool(re.match(r'[^@]+@[^@]+\.[^@]+', email_address))
 
 
 def validate_username(username):
@@ -25,10 +33,10 @@ def validate_username(username):
   if not regex_match:
     return (False, 'Username must match expression [a-z0-9_]+')
 
-  length_match = (len(username) >= MIN_LENGTH and len(username) <= MAX_LENGTH)
+  length_match = (len(username) >= MIN_USERNAME_LENGTH and len(username) <= MAX_USERNAME_LENGTH)
   if not length_match:
     return (False, 'Username must be between %s and %s characters in length' %
-            (MIN_LENGTH, MAX_LENGTH))
+            (MIN_USERNAME_LENGTH, MAX_USERNAME_LENGTH))
 
   return (True, '')
 
@@ -58,9 +66,20 @@ def generate_valid_usernames(input_username):
   if prefix.endswith('_'):
     prefix = prefix[0:len(prefix) - 1]
 
-  num_filler_chars = max(0, MIN_LENGTH - len(prefix))
+  num_filler_chars = max(0, MIN_USERNAME_LENGTH - len(prefix))
 
-  while num_filler_chars + len(prefix) <= MAX_LENGTH:
+  while num_filler_chars + len(prefix) <= MAX_USERNAME_LENGTH:
     for suffix in _gen_filler_chars(num_filler_chars):
       yield prefix + suffix
     num_filler_chars += 1
+
+
+def is_json(value):
+  if ((value.startswith('{') and value.endswith('}')) or
+      (value.startswith('[') and value.endswith(']'))):
+    try:
+      json.loads(value)
+      return True
+    except TypeError:
+      return False
+