Re: Improve the transaction compensation mechanism for FSM
It's quite important that we can get the feedback from Omega when calling the compensation method. +1 for this PR (we already merged it). Current we also need to update the status of the transaction in Alpha to keep the track of whole process. Willem Jiang Twitter: willemjiang Weibo: 姜宁willem On Mon, Nov 25, 2019 at 5:13 PM Zhang Lei wrote: > > Hi, Pack Team > > Currently, Alpha compensation mechanism has some defects [1], I plan to > solve this problem step by step [2] > > Step1: Modify the OnConnected method to bidirectional streaming RPC > >This will be needed for the Step2 > > Step2: Custom compensation exception rules to distinguish between business > compensation exceptions and framework compensation exceptions for FSM. > >After calling the compensation method, Alpha needs to wait for > Omega to send a compensation result message. The message type is as follows: > >Successful compensation: >Business compensation failure：business code throws an exception, > Do not switch Omega instance and retry（Retry rule is implemented in the > Step3） >Omega compensation failure: omega code throws an exception, > switch other Omega instance and retry（Retry rule is implemented in the > Step3） > > > Step3. Added retry and timeout rule to compensate for failures > >Exceeded the number of retries or timeout will change state to > suspended > > Any Suggestion? > > [1] https://github.com/apache/servicecomb-pack/issues/590 > [2] https://github.com/apache/servicecomb-pack/pull/607 > > Best regards, > Lei Zhang
Re: Improve the transaction compensation mechanism for FSM
It looks good to me.
Willem Jiang
Twitter: willemjiang
Weibo: 姜宁willem
On Mon, Nov 25, 2019 at 9:35 PM Zhang Lei wrote:
>
> Hi,
>
> Yes, they are class exception, Maybe the following name will be better
>
> class BusinessCompensationFailureException
> class OmegaConnectedException
>
> My idea is to catch an exception and send a compensation result in the
> compensation method[1] on the Omega side. You can see it in the following
> TODO position
>
> public void apply(String globalTxId, String localTxId, String
> callbackMethod, Object... payloads) {
> CallbackContextInternal contextInternal = contexts.get(callbackMethod);
> String oldGlobalTxId = omegaContext.globalTxId();
> String oldLocalTxId = omegaContext.localTxId();
> try {
> omegaContext.setGlobalTxId(globalTxId);
> omegaContext.setLocalTxId(localTxId);
> contextInternal.callbackMethod.invoke(contextInternal.target, payloads);
> LOG.info("Callback transaction with global tx id [{}], local tx id
> [{}]", globalTxId, localTxId);
>
> // TODO send TxCompensateSucceedAckEvent to Alpha
>
> } catch (IllegalAccessException | InvocationTargetException e) {
> LOG.error(
> "Pre-checking for callback method " +
> contextInternal.callbackMethod.toString()
> + " was somehow skipped, did you forget to configure callback
> method checking on service startup?",
> e);
>
> // TODO send TxCompensateFailedAckEvent to Alpha
>
> } finally {
> omegaContext.setGlobalTxId(oldGlobalTxId);
> omegaContext.setLocalTxId(oldLocalTxId);
> }
> }
>
>
> Alpha waits for compensation result and catching exception after calling
> compensation method
>
> 1. Received TxCompensateSucceedAckEvent: transaction completed
> 2. Received TxCompensateFailedAckEvent: throw
> BusinessCompensationFailureException
> 3. catch other exception throw OmegaConnectedException
>
>
> [1]
> https://github.com/apache/servicecomb-pack/blob/a89c7cd8b416c9b281fdbe28644cb6b7e2e78f91/omega/omega-context/src/main/java/org/apache/servicecomb/pack/omega/context/CallbackContext.java#L43
>
> [2]
> https://github.com/apache/servicecomb-pack/blob/694b8d701097226d898e7a342c902ff711caa3cf/alpha/alpha-server/src/main/java/org/apache/servicecomb/pack/alpha/server/fsm/GrpcOmegaCallback.java#L35
>
>
> Best regards,
> Lei Zhang
>
> On November 25, 2019 at 7:49:47 PM, Zheng Feng (zh.f...@gmail.com) wrote:
>
> Hi,
>
> I wonder how we can diff the "Omega compensation failure" from the
> "Business compensation failure" ? the different exception classes ?
>
> Zhang Lei 于2019年11月25日周一 下午5:32写道：
>
> > Hi, Pack Team
> >
> > Currently, Alpha compensation mechanism has some defects [1], I plan to
> > solve this problem step by step [2]
> >
> > Step1: Modify the OnConnected method to bidirectional streaming RPC
> >
> > This will be needed for the Step2
> >
> > Step2: Custom compensation exception rules to distinguish between
> business
> > compensation exceptions and framework compensation exceptions for FSM.
> >
> > After calling the compensation method, Alpha needs to wait for
> > Omega to send a compensation result message. The message type is as
> > follows:
> >
> > Successful compensation:
> > Business compensation failure：business code throws an exception,
> > Do not switch Omega instance and retry（Retry rule is implemented in the
> > Step3）
> > Omega compensation failure: omega code throws an exception,
> > switch other Omega instance and retry（Retry rule is implemented in the
> > Step3）
> >
> >
> > Step3. Added retry and timeout rule to compensate for failures
> >
> > Exceeded the number of retries or timeout will change state to
> > suspended
> >
> > Any Suggestion?
> >
> > [1] https://github.com/apache/servicecomb-pack/issues/590
> > [2] https://github.com/apache/servicecomb-pack/pull/607
> >
> > Best regards,
> > Lei Zhang
> >
> >
> > Best regards,
> > Lei Zhang
> >
Re: Improve the transaction compensation mechanism for FSM
Hi,
Yes, they are class exception, Maybe the following name will be better
class BusinessCompensationFailureException
class OmegaConnectedException
My idea is to catch an exception and send a compensation result in the
compensation method[1] on the Omega side. You can see it in the following
TODO position
public void apply(String globalTxId, String localTxId, String
callbackMethod, Object... payloads) {
CallbackContextInternal contextInternal = contexts.get(callbackMethod);
String oldGlobalTxId = omegaContext.globalTxId();
String oldLocalTxId = omegaContext.localTxId();
try {
omegaContext.setGlobalTxId(globalTxId);
omegaContext.setLocalTxId(localTxId);
contextInternal.callbackMethod.invoke(contextInternal.target, payloads);
LOG.info("Callback transaction with global tx id [{}], local tx id
[{}]", globalTxId, localTxId);
// TODO send TxCompensateSucceedAckEvent to Alpha
} catch (IllegalAccessException | InvocationTargetException e) {
LOG.error(
"Pre-checking for callback method " +
contextInternal.callbackMethod.toString()
+ " was somehow skipped, did you forget to configure callback
method checking on service startup?",
e);
// TODO send TxCompensateFailedAckEvent to Alpha
} finally {
omegaContext.setGlobalTxId(oldGlobalTxId);
omegaContext.setLocalTxId(oldLocalTxId);
}
}
Alpha waits for compensation result and catching exception after calling
compensation method
1. Received TxCompensateSucceedAckEvent: transaction completed
2. Received TxCompensateFailedAckEvent: throw
BusinessCompensationFailureException
3. catch other exception throw OmegaConnectedException
[1]
https://github.com/apache/servicecomb-pack/blob/a89c7cd8b416c9b281fdbe28644cb6b7e2e78f91/omega/omega-context/src/main/java/org/apache/servicecomb/pack/omega/context/CallbackContext.java#L43
[2]
https://github.com/apache/servicecomb-pack/blob/694b8d701097226d898e7a342c902ff711caa3cf/alpha/alpha-server/src/main/java/org/apache/servicecomb/pack/alpha/server/fsm/GrpcOmegaCallback.java#L35
Best regards,
Lei Zhang
On November 25, 2019 at 7:49:47 PM, Zheng Feng (zh.f...@gmail.com) wrote:
Hi,
I wonder how we can diff the "Omega compensation failure" from the
"Business compensation failure" ? the different exception classes ?
Zhang Lei 于2019年11月25日周一 下午5:32写道：
> Hi, Pack Team
>
> Currently, Alpha compensation mechanism has some defects [1], I plan to
> solve this problem step by step [2]
>
> Step1: Modify the OnConnected method to bidirectional streaming RPC
>
> This will be needed for the Step2
>
> Step2: Custom compensation exception rules to distinguish between
business
> compensation exceptions and framework compensation exceptions for FSM.
>
> After calling the compensation method, Alpha needs to wait for
> Omega to send a compensation result message. The message type is as
> follows:
>
> Successful compensation:
> Business compensation failure：business code throws an exception,
> Do not switch Omega instance and retry（Retry rule is implemented in the
> Step3）
> Omega compensation failure: omega code throws an exception,
> switch other Omega instance and retry（Retry rule is implemented in the
> Step3）
>
>
> Step3. Added retry and timeout rule to compensate for failures
>
> Exceeded the number of retries or timeout will change state to
> suspended
>
> Any Suggestion?
>
> [1] https://github.com/apache/servicecomb-pack/issues/590
> [2] https://github.com/apache/servicecomb-pack/pull/607
>
> Best regards,
> Lei Zhang
>
>
> Best regards,
> Lei Zhang
>
Re: Improve the transaction compensation mechanism for FSM
Hi, I wonder how we can diff the "Omega compensation failure" from the "Business compensation failure" ? the different exception classes ? Zhang Lei 于2019年11月25日周一 下午5:32写道： > Hi, Pack Team > > Currently, Alpha compensation mechanism has some defects [1], I plan to > solve this problem step by step [2] > > Step1: Modify the OnConnected method to bidirectional streaming RPC > >This will be needed for the Step2 > > Step2: Custom compensation exception rules to distinguish between business > compensation exceptions and framework compensation exceptions for FSM. > >After calling the compensation method, Alpha needs to wait for > Omega to send a compensation result message. The message type is as > follows: > >Successful compensation: >Business compensation failure：business code throws an exception, > Do not switch Omega instance and retry（Retry rule is implemented in the > Step3） >Omega compensation failure: omega code throws an exception, > switch other Omega instance and retry（Retry rule is implemented in the > Step3） > > > Step3. Added retry and timeout rule to compensate for failures > >Exceeded the number of retries or timeout will change state to > suspended > > Any Suggestion? > > [1] https://github.com/apache/servicecomb-pack/issues/590 > [2] https://github.com/apache/servicecomb-pack/pull/607 > > Best regards, > Lei Zhang > > > Best regards, > Lei Zhang >
Improve the transaction compensation mechanism for FSM
Hi, Pack Team Currently, Alpha compensation mechanism has some defects [1], I plan to solve this problem step by step [2] Step1: Modify the OnConnected method to bidirectional streaming RPC This will be needed for the Step2 Step2: Custom compensation exception rules to distinguish between business compensation exceptions and framework compensation exceptions for FSM. After calling the compensation method, Alpha needs to wait for Omega to send a compensation result message. The message type is as follows: Successful compensation: Business compensation failure：business code throws an exception, Do not switch Omega instance and retry（Retry rule is implemented in the Step3） Omega compensation failure: omega code throws an exception, switch other Omega instance and retry（Retry rule is implemented in the Step3） Step3. Added retry and timeout rule to compensate for failures Exceeded the number of retries or timeout will change state to suspended Any Suggestion? [1] https://github.com/apache/servicecomb-pack/issues/590 [2] https://github.com/apache/servicecomb-pack/pull/607 Best regards, Lei Zhang Best regards, Lei Zhang
Improve the transaction compensation mechanism for FSM
Hi, Pack Team Currently, Alpha compensation mechanism has some defects [1], I plan to solve this problem step by step [2] Step1: Modify the OnConnected method to bidirectional streaming RPC This will be needed for the Step2 Step2: Custom compensation exception rules to distinguish between business compensation exceptions and framework compensation exceptions for FSM. After calling the compensation method, Alpha needs to wait for Omega to send a compensation result message. The message type is as follows: Successful compensation: Business compensation failure：business code throws an exception, Do not switch Omega instance and retry（Retry rule is implemented in the Step3） Omega compensation failure: omega code throws an exception, switch other Omega instance and retry（Retry rule is implemented in the Step3） Step3. Added retry and timeout rule to compensate for failures Exceeded the number of retries or timeout will change state to suspended Any Suggestion? [1] https://github.com/apache/servicecomb-pack/issues/590 [2] https://github.com/apache/servicecomb-pack/pull/607 Best regards, Lei Zhang
