# Buggy code
def evaluate(self, image_obj, context):
    attr = self.attribute.value()
    check = self.check.value()
    rval = self.check_value.value()

    if not attr or not check:
        return

    op = self.__ops__.get(check)
    if op is None or op.requires_rvalue and not rval:
        # Raise exception or fall thru
        return

    img_val = self.__valid_attributes__[attr](image_obj)
    # Make consistent types (specifically for int/float/str)
    if type(img_val) in [str, int, float, str]:
        rval = type(img_val)(rval)

    if op.eval_function(img_val, rval):
        self._fire(
            msg="Attribute check for attribute: '{}' check: '{}' check_value: '{}' matched image value: '{}'".format(
                attr, check, (str(rval) if rval is not None else ""), img_val
            )
        )


# Traceback (ValueError)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] Traceback (most recent call last):
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/gate.py", line 234, in execute
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     self.evaluate(image_obj, context)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/gates/image_metadata.py", line 59, in evaluate
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     rval = type(img_val)(rval)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] ValueError: invalid literal for int() with base 10: '4gb'
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] During handling of the above exception, another exception occurred:
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] Traceback (most recent call last):
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/bundles.py", line 453, in execute
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     self.configured_trigger.execute(image_obj, exec_context)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/gate.py", line 237, in execute
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     raise TriggerEvaluationError(trigger=self, message='Error executing gate {} trigger {} with params: {}. Msg: {}'.format(self.gate_cls.__gate_name__, self.__trigger_name__, self.eval_params, e.message))
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] AttributeError: 'ValueError' object has no attribute 'message'
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] During handling of the above exception, another exception occurred:
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] Traceback (most recent call last):
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/api/controllers/synchronous_operations.py", line 481, in check_user_image_inline
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     eval_result = executable_bundle.execute(img_obj, tag, ExecutionContext(db_session=db, configuration={}))
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/bundles.py", line 1260, in execute
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     bundle_exec = self._process_mapping_result(bundle_exec, image_object, tag, context)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/bundles.py", line 1207, in _process_mapping_result
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     errors, policy_decision = evaluated_policy.execute(image_obj=image_object, context=context)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/bundles.py", line 596, in execute
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     errs, matches = rule.execute(image_obj=image_obj, exec_context=exec_context)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/engine/policy/bundles.py", line 458, in execute
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     raise TriggerEvaluationError(trigger=self.configured_trigger, message='Could not evaluate trigger due to error in evaluation execution')
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] anchore_engine.services.policy_engine.engine.policy.exceptions.TriggerEvaluationError: TriggerEvaluationError: severity:error message:Trigger evaluation failed for gate metadata and trigger attribute, with parameters: ([]) due to: Could not evaluate trigger due to error in evaluation execution
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] During handling of the above exception, another exception occurred:
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-] Traceback (most recent call last):
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/apis/authorization.py", line 339, in inner_wrapper
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     return f(*args, **kwargs)
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/anchore_engine/services/policy_engine/api/controllers/synchronous_operations.py", line 484, in check_user_image_inline
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     abort(Response(response='Cannot execute given policy against the image due to errors executing the policy bundle: {}'.format(e.message), status=500))
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]   File "/usr/local/lib/python3.6/dist-packages/werkzeug/exceptions.py", line 707, in abort
engine-policy-engine_1  | [service:policy-engine] 2019-01-11 05:49:12+0000 [-]     return _aborter(status, *args, **kwargs)

# Fixed code
def evaluate(self, image_obj, context):
    attr = self.attribute.value()
    check = self.check.value()
    rval = self.check_value.value()

    if not attr or not check:
        return

    op = self.__ops__.get(check)
    if op is None or op.requires_rvalue and not rval:
        # Raise exception or fall thru
        return

    img_val = self.__valid_attributes__[attr][0](image_obj)
    # Make consistent types (specifically for int/float/str)
    if type(img_val) in [int, float, str]:
        if attr == "size":
            rval = convert_bytes_size(rval)
        else:
            rval = type(img_val)(rval)

    if op.eval_function(img_val, rval):
        self._fire(
            msg="Attribute check for attribute: '{}' check: '{}' check_value: '{}' matched image value: '{}'".format(
                attr, check, (str(rval) if rval is not None else ""), img_val
            )
        )