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POMasstransit consumer death - Peek()
 

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    <p>I am curious as to if MassTransit consumers can Peek() a MSMQ queue before actually retrieving the msg.</p> <p>What the steps/process is:</p> <p>1) Msg sent to queue</p> <p>2) Consumers gets it and has to do a DB update -- takes about 5 seconds</p> <p>3) Consumer has to do second round of updates if the first worked.</p> <p>My problem is, how can I handle the case that if the first DB update fails that the message stays in the queue (i.e. network problem and can't get to db).</p> <p>Currently as soon as it reads the msg from the queue it removes it and then it just disappears if the DB updates fail..</p> <p>Additionally, how can I handle a power failure -- I mean if half way through a 'job' by a consumer, whatever that is (db update or something else) and the power dies etc, how can I re-run the process on the msg in the queue? Lets say the job (in my current instance anyway) is pushing a new row to a table. I mean I can write the code to first check if the row is there and if it is then drop the message and if not then run the task, but how can I get it to re-run the whole process in the first place?</p> <p>I have read up that I could <code>Peek()</code> the queue and then run the task and then read the queue msg for real and remove it, but I cannot for the life of me figure out if that works with mass transit... bit lost...</p> <p>Additionally I am aware that Masstransit has <code>.RetryLater</code> but then do I use that in the process? Is it <code>Initially</code> --> <code>When</code> --> <code>Then</code> --> <code>.RetryLater</code> in the saga??</p> <p>Any pointers would be appeciated</p> <p>Kindest Regards Robin</p> <p>EDIT</p> <p>PS: I am using a saga....</p> <pre><code>Define(() =&gt; { RemoveWhen(saga =&gt; saga.CurrentState == Completed); Initially( When(NewAC) .Then((saga, message) =&gt; saga.ProcessPSM(message), InCaseOf&lt;Exception&gt;() .TransitionTo(Problem) ) .Then((saga, message) =&gt; saga.PostProcessPSM()) .Complete() ); During(Problem, When(Waiting) // NOTE: THIS DOES NOT WORK!!!! .RetryLater() ); }); </code></pre> <p>The RetryLater throw an error of: "The message cannot be accepted by an existing saga"</p> <p>I am not sure how else I can access the 'RetryLater". </p>
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