https://citconf.com/wiki/index.php?action=history&feed=atom&title=MicroservicesComboStyle 2026-06-03T23:31:15Z Revision history for this page on the wiki MediaWiki 1.43.8 https://citconf.com/wiki/index.php?title=MicroservicesComboStyle&diff=15743&oldid=prev 2014-09-21T10:34:41Z

<p>Created page with &quot;* What do we think micro services are.. * We want to be able to rewrite services and remove legacy code ** Make all &quot;objects&quot; separate processes that can run on diff...&quot;</p> <p><b>New page</b></p><div>* What do we think micro services are..<br /> * We want to be able to rewrite services and remove legacy code<br /> ** Make all &quot;objects&quot; separate processes that can run on different machines<br /> ** Rather than single process tight binding between classes<br /> ** We could run two of them on the same box to scale<br /> ** Ability to rewrite each object even using different languages if required<br /> ** Could communicate using direct RPC, e.g. as a fully meshed graph<br /> *** Would require agreement on contracts between objects<br /> *** Not favoured approach<br /> *** &quot;Orchestrated style&quot;<br /> ** Combo Model<br /> *** Tuple Spaces - Immutable data store<br /> *** Objects publish immutable facts to central store<br /> *** Objects can publish requests to store<br /> *** Other objects can publish responses to requests to store<br /> *** Objects interested in responses can take those and relay to end users/devices<br /> *** Basically it&#039;s pub/sub<br /> *** Can add other subscribers after the fact and consume existing events<br /> *** Promotes loose coupling<br /> *** &quot;Combo Style&quot;<br /> *** What about large messages, too large to pass round<br /> **** Upload the large payload to a repository e.g. via webservice<br /> **** Publish a &quot;pointer&quot; to the data<br /> *** Why not just do RPC to request data directly<br /> *** How do you handle errors<br /> **** If you don’t get a response in a given time frame there is a problem<br /> **** The client only needs to care the other service wsa unavailable and timed out, it should not concern itself with the specific error<br /> *** How do you handle say an order fulfilment scenario where the micro service handling fulfilment was down when the fulfilment request was sent<br /> **** In our case, each subscriber e.g the OrderProcessingService has its own unique persistent queue of messages it will resume processing when it starts up again<br /> *** How do you &quot;fix&quot; data<br /> **** E.g. order sent with wrong email<br /> **** We want to correct the email without double fullfiilling the order<br /> **** The order fulfilment step needs to be idempotent<br /> **** The email sending service would not be, it would send the confirmation email again regardless<br /> **** Each service will still hold its own state, or have its own database<br /> *** When would you switch a service to use queues/RabbitMQ<br /> * Prediction: 20/09/14 DS: Formal verification of microservices system proof, using COQ? &lt;- fix me</div>

Douglassquirrel