Hi everyone, we've discussed about serialization formats a few times on this list, I think the discussion here: Best practices using Akka Persistence with long-running projects? <https://groups.google.com/forum/#!searchin/akka-user/Best$20practices$20using$20Akka$20Persistence$20with$20long-running$20projects/akka-user/xNtxm8sLtO0/6FcJNbbgoY0J> was one of the most interesting ones, listing the multiple available serialization formats and their tradeoffs.
Also, protocol buffers supports maps since 3.0+: https://github.com/google/protobuf/releases/tag/v3.0.0-alpha-2 Avro does support maps as well: http://avro.apache.org/docs/1.3.0/spec.html The serialization format you pick is one of the most important choices when designing these systems - you should take some time and research all available options. On Tue, Apr 21, 2015 at 7:00 PM, Jason Law <ja...@lawcasa.com> wrote: > Martin, I'm curious about your protobuf recommendation. I plan to persist > events and snapshots, and evolve the schema over time. Protobuf seems to > have the best support for evolution, but it's not perfect, and I feel quite > constrained by the generated code. For example, if I'm persisting a > collection of objects, but the way I want to use that collection when > deserialized is in a Map, then I've got to go through an extra > transformation (Seq to Map). But maybe I'm over thinking it, or thinking > about this challenge in the wrong way. Any insights? > > On Monday, May 19, 2014 at 10:05:56 PM UTC-6, Martin Krasser wrote: >> >> Hi Odd, >> >> why have you chosen this versioning approach instead of a protobuf based >> one, for example? What are the advantages? >> >> On 19.05.14 14:08, Odd Möller wrote: >> >> Hi! >> >> We have a versioning extension that we are experimenting with at the >> moment (it is quite experimental at this point and completely without >> tests): >> https://github.com/odd/akka/tree/wip-persistence-odd/akka-contrib/src/main/scala/akka/contrib/persistence/versioning >> >> The basic idea is to attach a version to the actual data to be >> persisted and then when saving the data, instead of serializing the data >> class as is, save a tuple containing the data of the fields of the class. >> Then at load time you can transform historic versions of the saved data to >> the latest version (based on the attached version). >> >> For example: >> >> import akka.contrib.persistence.versioning._ >> >> // Version 1 -- present in the event log but no longer available at >> runtime >> // case class Name(first: String, last: String) extends Versioned[Name] >> >> // Version 2 -- current version of the class at runtime >> case class Name(first: String, last: String, title: Option[String] = >> None) extends Versioned[Name] >> >> object Name extends Versioned.Companion[Name] { >> override def apply(data: (Version, Any)): Name = { >> case (Version.Major(1), (first: String, last: String)) => Name(first, >> last) >> case (Version.Major(2), (first: String, last: String, title: >> Option[String])) => Name(first, last, title) >> case (v, d) => throw new IllegalStateException(s"Unknown version >> encountered [version: $v, data: $d]") >> } >> } >> >> The versioned serializer needs to be present in the akka config: >> >> serializers { >> versioned = "akka.contrib.persistence.versioning.VersionedSerializer" >> } >> serialization-bindings { >> "akka.contrib.persistence.versioning.Versioned" = versioned >> } >> >> >> On Thu, May 15, 2014 at 7:41 PM, Per Johansson <per.j.j...@gmail.com> >> wrote: >> >>> What about using "versioned" objects (like Foo_v01, Foo_v02) and convert >>> to the latest version when reading a snapshot? >>> >>> Anyone with experience of that approach? >>> >>> Was thinking it might be less work if you want to have e.g. maps after >>> derserialization? (maps not supported in protobuf) >>> >>> /Per >>> >>> On Thursday, 8 May 2014 09:47:46 UTC+1, Martin Krasser wrote: >>> >>>> >>>> On 08.05.14 10:43, Tim Pigden wrote: >>>> >>>> Hi >>>> I've found a new thing to worry about :-) >>>> If I use an eventsource model and content myself with the default >>>> serialization and akka persistence, what's the likelihood of my serialized >>>> objects becoming unreadable in the future? What's the long-term stability >>>> of the default akka serialization mechanism? >>>> >>>> >>>> By default, events are serialized with Akka's Java serializer. >>>> >>>> Is there a recommendation? >>>> >>>> >>>> Use a custom >>>> <http://doc.akka.io/docs/akka/2.3.2/scala/persistence.html#custom-serialization> >>>> protobuf (or similar) serializer to serialize your events. This will >>>> support backwards compatible changes to your event schema. >>>> >>>> Tim >>>> -- >>>> >>>>>>>>>> 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 akka-user+...@googlegroups.com. >>>> To post to this group, send email to akka...@googlegroups.com. >>>> >>>> Visit this group at http://groups.google.com/group/akka-user. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>>> >>>> -- >>>> Martin Krasser >>>> >>>> blog: http://krasserm.blogspot.com >>>> code: http://github.com/krasserm >>>> twitter: http://twitter.com/mrt1nz >>>> >>>> -- >>> >>>>>>>>>> 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 akka-user+...@googlegroups.com. >>> To post to this group, send email to akka...@googlegroups.com. >>> Visit this group at http://groups.google.com/group/akka-user. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> -- >> Martin Krasser >> >> blog: http://krasserm.blogspot.com >> code: http://github.com/krasserm >> twitter: http://twitter.com/mrt1nz >> >> -- > >>>>>>>>>> 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 akka-user+unsubscr...@googlegroups.com. > To post to this group, send email to akka-user@googlegroups.com. > Visit this group at http://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. > -- Cheers, Konrad 'ktoso' Malawski Akka <http://akka.io/> @ Typesafe <http://typesafe.com/> -- >>>>>>>>>> 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. 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