Thank you понеділок, 25 вересня 2017 р. 21:36:08 UTC+3 користувач Justin du coeur написав: > > Sure, but I think you're thinking about it incorrectly. Don't worry about > creating the Sharding entity itself, which has no lasting effect -- > instead, focus on not *persisting* anything unless the wallet is already > valid. The preStart idea isn't bad, but probably expensive (assuming the > external DB is a bit expensive, which is typically true), so you don't want > to *always* check it, just when the wallet is new. > > Instead, I would send a message to the wallet, which causes the wallet > entity to be created and to "recover". Recovery finds that there is no > history for the wallet, so post-recovery the actor checks the external DB. > If it finds that the wallet has been created, great -- it persists an event > that says so. Otherwise it returns a message saying "this wallet doesn't > exist yet", and kills itself. > > On Mon, Sep 25, 2017 at 9:47 AM, Evgeny Shepelyuk <[email protected] > <javascript:>> wrote: > >> Hello >> >> I'd like to implement cluster sharding enabled service with following >> scenario >> >> # *Wallet *service manages users' wallets >> # Each *wallet* is represented as persistent actors / shard entity >> # Shard clients are sending deposit / withdraw commands to wallets >> # Wallet creation is a dedicated business procedure and can't be just a >> creating new actor by *ShardRegion *actor >> >> What we're trying to achieve is >> >> # before processing deposit / withdraw commands to check if some external >> DB contains record about *wallet *registration >> # create shard entity only if *wallet *is registered before >> >> Is this a valid scenario for akka cluster sharding and if yes - how can >> this be achieved ? >> >> Unfortunately haven't find proper information in Internet., the only >> option I see now - is to check external DB in preStart method of shard >> entity. >> >> >> >> -- >> >>>>>>>>>> Read the docs: http://akka.io/docs/ >> >>>>>>>>>> Check the FAQ: >> http://doc.akka.io/docs/akka/current/additional/faq.html >> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >> --- >> You received this message because you are subscribed to the Google Groups >> "Akka User List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to [email protected] >> <javascript:>. >> Visit this group at https://groups.google.com/group/akka-user. >> For more options, visit https://groups.google.com/d/optout. >> > >
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