Currently, the size of an action result is not checked by the system and
can exceed the assumed limit of 1MB. This will manifest itself in blocking
invokes will have at least a 30s delay on getting their results. Similarly
larger than allowed invoke time parameters are not rejected as early as
they should be in the pipeline. This is a standing open defect you can read
more about here [1] along with my proposed solution [2] which I include
below for convenience.
1. Response is sized by the invoker.
1. If it exceeds the system limit, the invoker will reject it.
2. If it is within the limits, it will be processed as usual.
2. When the invoker rejects an action response, it will do the
following:
1. Construct an error response object with a message explaining the
failure
2. In addition, it will provide as a debugging aid a partial result
that contains as many of the top level fields from the
dictionary response
into the error object.
3. The error response for large responses shall include:
1. "Action result of X MB exceeds system limit of Y MB".
2. The number of top level fields contained in the response and how
many are actually included in the partial response.
As part of doing this work, I will also apply the same technique to reject
large incoming payloads which currently get rejected a bit later in the
pipeline than they should.
Comments and feedback welcomed and appreciated.
-r
[1] https://github.com/openwhisk/openwhisk/issues/566
[2] https://github.com/openwhisk/openwhisk/issues/566#issuecomment-275687757
