On Mon, May 8, 2017 at 7:33 PM, Lakmal Warusawithana <lak...@wso2.com> wrote:
> Hi Thilini, > > We had an offline discussion. Please see following scenarios and flow. > Generally we need to add timestamp with the event. GW need to validate its > action with the API core with timestamp of the event. This is valid for all > event with relevant action. Believed these flow will solve the issue. > Scenario 1: Success MB connection & Success DB entry > > Publisher UI: > > Create API à API Core > > > > API Core: > > API Core à MB: Publish to topic API + Event + Timestamp > > Success > > API Core à DB > > Success > > API Core à API Publisher: API Create Success > > > > API GW: > > MB à GW: received API + Event + Timestamp > > GW à API Core: Service call to Core with API + Event + > Timestamp > > If matching with timestamp, retrieve the API > > > Scenario 2: Success MB connection & Failed DB entry > > Publisher UI: > > Create API à API Core > > > > API Core: > > API Core à MB: Publish to topic API + Event + Timestamp > > Success > > API Core à DB > > Failed > > API Core à API Publisher: Don’t allow save: ERROR > > > > API GW: > > MB à GW: received API + Event + Timestamp > > GW à API Core: Request API with API + Event + Timestamp > > If not matching with timestamp ignore the event. No action > > > Scenario 3: Failed MB connection > > Publisher UI: > > Create API à API Core > > > > API Core: > > API Core à MB: Publish to topic API + Event + Timestamp > > Failed > > API Core à API Publisher: Don’t allow save: ERROR Failed > > > So in summary, what we are doing here is persist in API Core DB only if publisihing to the MB is successful. First publish and then persist? isf so +1 > > > On Mon, May 8, 2017 at 2:38 PM, Thilini Shanika <thili...@wso2.com> wrote: > >> Hi All, >> >> As per the APIM 3.0.0 architecture, the events such as APIM create, >> update, delete, subscription create etc are notified to gateways through >> JMS Topic in the broker. Thus, we need to smoothly handle the scenarios >> like *broker not available* and *APIM to Broker connection(network) >> failure,* since the flow cannot be completed without notifying the >> gateway (A blocking call). Ideally, if the API action cannot be completed >> due to broker connection failure, the users should be notified about the >> failure and the action should be rolled back. >> >> But, we are facing some difficulties to handle topic publishing failures >> and rollback API action(API create, API state change, API update, API >> delete, subscription create, subscription block) since the API action is >> getting persisted in APIM db layer prior to publishing to Gateway. >> >> For example, if an API create request is initiated from API core, first, >> the API will be persisted in db layer. Then the API create event will be >> published to Topic and the registered gateways will be notified. But if the >> broker publishing step is failed, the gateways will not be notified on the >> newly created API so that the API won't be published to gateway. This might >> lead the API to go to an inconsistent/partially created state (API is >> successfully created in db, but not pushed to gateway). >> >> >> Currently, we have not implemented any mechanism to >> >> - Rollback the action, or >> - Persist the inconsistent state as a flag in API so that the user is >> aware of the inconsistent state >> >> What would be the best way to handle broker failures? Any suggestions? >> >> Thanks >> -- >> Thilini Shanika >> Senior Software Engineer >> WSO2, Inc.; http://wso2.com >> 20, Palmgrove Avenue, Colombo 3 >> >> E-mail: tgtshan...@gmail.com >> >> > > > -- > Lakmal Warusawithana > Director - Cloud Architecture; WSO2 Inc. > Mobile : +94714289692 <+94%2071%20428%209692> > Blogs : https://medium.com/@lakwarus/ > http://lakmalsview.blogspot.com/ > > > _______________________________________________ > Architecture mailing list > Architecture@wso2.org > https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture > > -- Thanks & Regards, Fazlan Nazeem *Senior Software Engineer* *WSO2 Inc* Mobile : +94772338839 <%2B94%20%280%29%20773%20451194> fazl...@wso2.com
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