I am in the full agreement with the proposed approach (risked to copy below,
let's see if email handles your diagrams):
* Single Engine handles multiple executions asynchronously, in non-blocking way.
* Persistence access only from API and/or Engine, Engine writes, API reads.
* Action runes don't talk to DB - it's very simple protocol and queue is
perfectly fine.
* This is scalable and as fault tolerant as underlying DB and Queue. Engine
restart is no loss of info with right persistense; ActionRunner restart is a
lost of Action, which can fail for 100 other reasons thus expected, and with
the right retry policy potentially recoverable.
I'll inline minor points in the etherpad.
API EngineQueueDatabaseWorkers
| | | | | || |
--- +-+ | | | | || |
|S| | | | | || |
|t| -- +-+ | | | || |
|a| | | - - - - - - - - || |
|r| | | - - - - t - - - - - - - - - +-+ |
|t| -- +-+ | | | | | | |
--- +-+ | | | | | | | |
| | +-+ - r - - - - - - - - - - +-+ |
--- +-+ | | | - - - - - - R| |
|I| | | | - - t - - - - - - - - - +-+ |
|n| | | | - - t - - - - - - - - - - - +-+
|f| | +-+| | | | | | |
|o| - - - - - - - - - - - - | | | | |
--- +-+ | +-+ - r - - - - - - - - - - -+-+ | |
| | | | - - - - - - R| | |
--- +-+ | +-+| | || | |
|S| -- +-+ | | | || | |
|t| | | - - - - - - - - || | |
|o| -- +-+ | | | || | |
|p| | +-+ - r - - - - - - - - - - - - +-+
--- +-+ | | | - - - - - - R| |
| | |%|| | || |
| | +-+| | || |
| | | | | || |
On Mar 31, 2014, at 4:09 AM, Kirill Izotov enyk...@stackstorm.com wrote:
I have an idea regarding engine design i want to share with you. But first,
it seems like we need a small overview of the current implementations.
I'm not sure how ML will react on a bunch of ASCII graphs, so here is an
etherpad:
https://etherpad.openstack.org/p/mistral-engine-overview-and-proposal
What do you think, guys, is this the way to go?
--
Kirill Izotov
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