Protobufs is what you want. Since you have the schema on server and client the
amount of data dictionary overhead per message is minimal - essentially numeric
tags and the raw data.
> On Dec 24, 2020, at 8:21 AM, Artur Vianna <lordhowen...@gmail.com> wrote:
>
>
> I will definitely explore your ideas, thanks for the insights. I'll let you
> know how it turned out in the end :D
>
> Thanks
>
>> On Thu, 24 Dec 2020, 06:59 Axel Wagner, <axel.wagner...@googlemail.com>
>> wrote:
>>> On Thu, Dec 24, 2020 at 6:35 AM Artur Vianna <lordhowen...@gmail.com> wrote:
>>
>>> Exposing the bytes would hurt the abstraction.
>>
>> I strongly disagree with this. Exposing the bytes would improve the
>> abstraction, by making the transmission- and encoding method orthogonal. And
>> as I said, you can still provide just as convenient a wrapper around it.
>>
>>> I will certainly look into Json and maybe MessagePack. But first i may
>>> fiddle with the gob source code, if my sanity allows it. If i can control
>>> when the type information is sent i may be able to fix this without
>>> changing the API. The ideal enconding would be a stateless gob, with the
>>> proper decoding/encoding "machines" set on either side when you call
>>> gob.Register, but i'm not sure of the feasibility of that.
>>
>> Sure, that's definitely possible. I factored that in, when I said "I think
>> it's far less effort to just use a different format than trying to make this
>> work with gob".
>>
>> But, of course, you do you. :) The decision of what API to expose and what
>> encoding scheme to use and how much work you are putting into what piece is
>> ultimately up to you :)
>>
>>>
>>>> On Wed, 23 Dec 2020, 21:55 Axel Wagner, <axel.wagner...@googlemail.com>
>>>> wrote:
>>>>> On Thu, Dec 24, 2020 at 1:08 AM Artur Vianna <lordhowen...@gmail.com>
>>>>> wrote:
>>>>
>>>>> Before using gob was using encoding.BinaryMarshaler, but that would mean
>>>>> the user of the api would need to implement a MarshalBinary for every
>>>>> type, which is kind of cumbersome.
>>>>>
>>>>> An option might be to let the user choose gob, BinaryMarshaler or Json
>>>>> etc to best fit the use case, but that takes the simplicity of only gobs
>>>>> away.
>>>>
>>>> I am all in favor of API simplicity, but gob just isn't super useful for
>>>> this. Not to repeat myself, but you should really at least try JSON - it
>>>> provides exactly the same convenience as gob, but doesn't suffer these
>>>> problems. It might have a bit more overhead and might even be costlier to
>>>> encode - but the savings from being able to eliminate duplicate effort
>>>> should offset that (and I'm not even super convinced - I don't think gob
>>>> is the most well-optimized encoding in the stdlib).
>>>>
>>>> But IMO, if you provide an API, the best solution is to a) just use
>>>> `[]byte` at the base-layer and then b) provide convenience-wrappers around
>>>> that for other formats. This lets the users decide what they want (they
>>>> might want something completely different anyway) while still providing a
>>>> decently convenient API for simple uses.
>>>>
>>>>>
>>>>> I did try your solution to reset the client too but i'm getting
>>>>> inconsistent behaviour, in one server it works and in another it doesn't
>>>>> ("corrupted data or unknown type"). I think synching the server and
>>>>> client will be error prone, while also increasing the use of network.
>>>>>
>>>>> The easiest solution now is to label the package for ≤32 players and test
>>>>> alternative encodings that keep the API as clean as with gob. I took a
>>>>> look at flatbuffers but it will be cumbersome for the user to create the
>>>>> builders, and i really wanted the simplest possible API.
>>>>>
>>>>> Maybe i should try UDP Broadcast too and see what happens, probably chaos
>>>>> :D
>>>>>
>>>>>
>>>>>> On Wed, 23 Dec 2020, 20:36 Axel Wagner, <axel.wagner...@googlemail.com>
>>>>>> wrote:
>>>>>> No, it wouldn't. Because the encoder keeps state about which
>>>>>> type-information it already sent and wouldn't sent it again - causing
>>>>>> the client to be unable to decode. So you'd also need a new encoder on
>>>>>> the server. And at that point, you're back to the status quo, with one
>>>>>> encoder per client and the duplication of encoding effort.
>>>>>>
>>>>>> A solution would, perhaps, be if the gob API would give you a way to
>>>>>> send *only* the type-info (so you could, if the connection breaks,
>>>>>> create a new encoder, send all the type info, and *then* multicast the
>>>>>> encoded values). But it doesn't.
>>>>>>
>>>>>> Really, I think it's far less effort to just use a different format (and
>>>>>> I would maintain that even json would probably be fine) than trying to
>>>>>> make this work with gob :)
>>>>>>
>>>>>> On Thu, Dec 24, 2020 at 12:20 AM Matthew Zimmerman
>>>>>> <mzimmer...@gmail.com> wrote:
>>>>>>> If you would "reset" each client with a new decoder each time you make
>>>>>>> a new encoder, everything should work fine. Just would take some
>>>>>>> coordination.
>>>>>>>
>>>>>>>> On Wed, Dec 23, 2020, 6:08 PM Artur Vianna <lordhowen...@gmail.com>
>>>>>>>> wrote:
>>>>>>>> I will look into other protocols, although for now the performance is
>>>>>>>> not an issue in servers with less than 100 players.
>>>>>>>>
>>>>>>>> The problem with io.MultiWriter is that a player inside the group may
>>>>>>>> disconnect or a new player may come in. This means a new
>>>>>>>> io.MultiWriter must be created each time you dispatch, since the group
>>>>>>>> may have changed in the meantime. This would also need a new encoder
>>>>>>>> and then the "duplicate type received" happens.
>>>>>>>>
>>>>>>>>> On Wed, 23 Dec 2020, 19:58 'Axel Wagner' via golang-nuts,
>>>>>>>>> <golang-nuts@googlegroups.com> wrote:
>>>>>>>>> The issue with that approach is that gob keeps state about which
>>>>>>>>> type-information it still has to send. So if you encode to, say, a
>>>>>>>>> bytes.Buffer, it would encode all type-info on every message sent,
>>>>>>>>> which is a significant overhead.
>>>>>>>>> TBH, I don't understand why `io.MultiWriter` wouldn't work. It would
>>>>>>>>> be helpful to see the code that causes the error message OP is seeing.
>>>>>>>>>
>>>>>>>>> However, really, gob just doesn't provide a good API for this sorta
>>>>>>>>> thing, as mentioned. The format itself is fine, but the stateful
>>>>>>>>> connection means that if you don't want to write *exactly* the same
>>>>>>>>> data in exactly the same order to all connections (which can perform
>>>>>>>>> poorly and lead to operational problems with timeouts and
>>>>>>>>> intermittently lost connections and the like), you are going to have
>>>>>>>>> a bad time.
>>>>>>>>> You honestly would fare better with a full-fledged RPC framework such
>>>>>>>>> as gRPC. Or, if you don't want the overhead of its IDL, even json.
>>>>>>>>> Because at least the "encode once, send to each client" is trivial to
>>>>>>>>> solve with that.
>>>>>>>>>
>>>>>>>>> But, that's just my 2¢ :)
>>>>>>>>>
>>>>>>>>>> On Wed, Dec 23, 2020 at 11:43 PM Robert Engels
>>>>>>>>>> <reng...@ix.netcom.com> wrote:
>>>>>>>>>> Yes, that is why you need to create your own protocol. Use the gob
>>>>>>>>>> to encode to a buffer then send the buffer on each of the
>>>>>>>>>> connections using your protocol.
>>>>>>>>>>
>>>>>>>>>>>> On Dec 23, 2020, at 4:19 PM, Matthew Zimmerman
>>>>>>>>>>>> <mzimmer...@gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> My understanding is that gob streams are unique.
>>>>>>>>>>>
>>>>>>>>>>> From https://golang.org/pkg/encoding/gob/
>>>>>>>>>>> "A stream of gobs is self-describing. Each data item in the stream
>>>>>>>>>>> is preceded by a specification of its type, expressed in terms of a
>>>>>>>>>>> small set of predefined types."
>>>>>>>>>>>
>>>>>>>>>>> In my own rudimentary understanding/terms, it sends the struct
>>>>>>>>>>> definition once, then uses shorthand for it afterwards. E.g, how
>>>>>>>>>>> many bytes and what order. If you mix and match streams that send
>>>>>>>>>>> definitions in different orders, then chaos ensues.
>>>>>>>>>>>
>>>>>>>>>>> I think this is why people use other encoders in the scenario
>>>>>>>>>>> you're taking about. For a one to one stream gob works great, but
>>>>>>>>>>> in this multi scenario I don't think it does.
>>>>>>>>>>>
>>>>>>>>>>> Matt
>>>>>>>>>>>
>>>>>>>>>>>> On Wed, Dec 23, 2020, 5:07 PM Artur Vianna
>>>>>>>>>>>> <lordhowen...@gmail.com> wrote:
>>>>>>>>>>>> If i create a bytes.Buffer and a gob.Encoder, each time i write to
>>>>>>>>>>>> a group of connections i get "duplicate type received" and if i
>>>>>>>>>>>> try and reuse the encoder, i get "corrupted data" and "unknown
>>>>>>>>>>>> type".
>>>>>>>>>>>> It seems i can't use both net.Conn.Write and gob.Encoder.Encode in
>>>>>>>>>>>> the same connection, i will try always encoding to a buffer in
>>>>>>>>>>>> both unicast and multicast like you said and report if it works.
>>>>>>>>>>>>
>>>>>>>>>>>>> On Wed, 23 Dec 2020, 18:49 Robert Engels, <reng...@ix.netcom.com>
>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>> You need to encode once to a byte array then send the byte array
>>>>>>>>>>>>> on each connection.
>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On Dec 23, 2020, at 3:45 PM, meera <lordhowen...@gmail.com>
>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I am trying to create a package for game servers using gob. The
>>>>>>>>>>>>>> current approach is an application level multicasting over TCP,
>>>>>>>>>>>>>> having a gob encoder and decoder for each player connection, and
>>>>>>>>>>>>>> set up a goroutine to receive and another to dispatch for each
>>>>>>>>>>>>>> one. The code for the dispatcher is here. But summarized, it
>>>>>>>>>>>>>> simply receives data from a channel and encodes it.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> The problem is that if i want to transmit a single piece of data
>>>>>>>>>>>>>> to all players, this piece of data is encoded again and again
>>>>>>>>>>>>>> for each connection, doing duplicate work. With less than 100
>>>>>>>>>>>>>> players this is not a problem, but with 300+ my machine is at
>>>>>>>>>>>>>> almost 100% usage and the profiler shows that most of it is
>>>>>>>>>>>>>> spent on encoding. Here's the issue on github.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I tryied using a io.MultiWriter but gob complains of duplicate
>>>>>>>>>>>>>> type received, and if i try to write the raw bytes from the
>>>>>>>>>>>>>> gob.Encoder i get corrupted data. An option is using UDP
>>>>>>>>>>>>>> Broadcasting but since gob expects a stream, i'm affraid i will
>>>>>>>>>>>>>> run into unexpected behavior when packets start to be lost and
>>>>>>>>>>>>>> fragmented.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Does gob expect a single encoder and decoder to own the stream?
>>>>>>>>>>>>>> Not allowing two encoders on the server for one decoder on the
>>>>>>>>>>>>>> client?
>>>>>>>>>>>>>> --
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>>>>>>>>>>>>
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>>>>>>>>>
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