If enabled, allow users and orgs to set their time machine expiration

Fixes https://www.pivotaltracker.com/story/show/142881203

util/config/validators/test/test_validate_timemachine.py

@@ -0,0 +1,23 @@
+import pytest
+
+from util.config.validators import ConfigValidationException
+from util.config.validators.validate_timemachine import TimeMachineValidator
+from util.morecollections import AttrDict
+
+@pytest.mark.parametrize('default_exp,options,expected_exception', [
+  ('2d', ['1w', '2d'], None),
+
+  ('2d', ['1w'], 'Default expiration must be in expiration options set'),
+  ('2d', ['2d', '1M'], 'Invalid tag expiration option: 1M'),
+])
+def test_validate(default_exp, options, expected_exception):
+  config = {}
+  config['DEFAULT_TAG_EXPIRATION'] = default_exp
+  config['TAG_EXPIRATION_OPTIONS'] = options
+
+  if expected_exception is not None:
+    with pytest.raises(ConfigValidationException) as cve:
+      TimeMachineValidator.validate(config, None, None)
+    assert str(cve.value) == str(expected_exception)
+  else:
+    TimeMachineValidator.validate(config, None, None)

util/config/validators/validate_timemachine.py

@@ -0,0 +1,25 @@
+import logging
+
+from util.config.validators import BaseValidator, ConfigValidationException
+from util.timedeltastring import convert_to_timedelta
+
+logger = logging.getLogger(__name__)
+
+class TimeMachineValidator(BaseValidator):
+  name = "time-machine"
+
+  @classmethod
+  def validate(cls, config, user, user_password):
+    try:
+      convert_to_timedelta(config['DEFAULT_TAG_EXPIRATION']).total_seconds()
+    except ValueError as ve:
+      raise ConfigValidationException('Invalid default expiration: %s' % ve.message)
+
+    if not config['DEFAULT_TAG_EXPIRATION'] in config['TAG_EXPIRATION_OPTIONS']:
+      raise ConfigValidationException('Default expiration must be in expiration options set')
+
+    for ts in config['TAG_EXPIRATION_OPTIONS']:
+      try:
+        convert_to_timedelta(ts)
+      except ValueError as ve:
+        raise ConfigValidationException('Invalid tag expiration option: %s' % ts)