Cloud Gaming Platform with Go

Go Conference 2021 Autumn

Transcript

1. © Black Inc.
   Cloud Gaming Platform
   with Go
   castaneai
   Backend engineer
   Black Inc.
   

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2. © Black Inc.
   Agenda
   ● Introduction of Cloud Gaming
   ● Backend Architecture and Go
   ○ Stateful game server
   ○ Video streaming
   ● Cloud Native Infrastructure
   ○ Cloud providers support
   ○ Build and deploy
   2
   

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3. © Black Inc.
   Introduction of
   Cloud Gaming
   

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4. © Black Inc.
   What is cloud gaming?
   Player Gaming Server
   Player Action
   Video Streaming
   4
   

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5. © Black Inc.
   OOParts
   Our cloud gaming platform for visual novels
   https://oo.parts
   5
   

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6. © Black Inc.
   Backend Architecture
   and Go
   

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7. © Black Inc.
   OOParts Architecture
   Frontend Backend
   7
   

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8. © Black Inc.
   92.6%
   8
   

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9. © Black Inc. 9
   

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10. © Black Inc.
    Why Go?
    How Go?
    

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11. © Black Inc.
    Stateful game server
    

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12. © Black Inc.
    Player Gaming Server
    Player Action
    Video Streaming
    Game Session
    12
    

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13. © Black Inc.
    Handling a stateful game server
    ● Game session is “Stateful”
    ○ Web-based frontend, but game server is NOT a HTTP Server
    ○ Long-time (1h~)
    ○ Resumable
    ---> Stateful is complex
    13
    

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14. © Black Inc.
    Handling a stateful game server
    ● How do we handle stateful?
    ● Real-world examples
    ○ TCP Socket
    ○ WebRTC Agent
    ○ ...
    14
    

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15. © Black Inc.
    Handling a stateful game server
    ● State machine
    Waiting For
    Session
    Starting Game
    Playing Game
    Waiting For
    Reconnect
    Shutdown
    15
    

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16. © Black Inc.
    Handling a stateful game server
    type State string
    const (
    StateWaitingForSession State = "WaitingForSession"
    StateStartingGame State = "StartingGame"
    StatePlayingGame State = "PlayingGame"
    ...
    )
    type StateLogic interface {
    Run(ctx context.Context, ts Transition) (State, Transition)
    }
    16
    

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17. © Black Inc.
    Handling a stateful game server
    17
    State machine loop & logging
    func (a *Agent) MainLoop(ctx context.Context) error {
    for {
    prevState := nextState
    nextState, transition = logic.Run(ctx, transition)
    log.Infof(" +++ State [%s] -> [%s]", prevState, nextState)
    ...
    

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18. © Black Inc.
    Handling asynchronous events
    ● Many asynchronous events on cloud gaming 😱
    Key-frame
    request
    Player
    disconnected
    SIGTERM
    game window
    resized
    game exited
    Player input
    Game Server
    18
    

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19. © Black Inc.
    Handling asynchronous events in Go
    ● Goroutine
    ● Channel
    19
    

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20. © Black Inc.
    Handling asynchronous events in Go
    select {
    }
    20
    

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21. © Black Inc.
    Handling asynchronous events in Go
    select {
    }
    Player
    disconnected
    SIGTERM
    game exited
    Player input
    case case case case ...
    ...
    21
    🎉
    

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22. © Black Inc.
    Stateful and asynchronous events
    select {
    }
    case return StateB
    case case State A
    select {
    }
    case case case return StateA
    State B
    22
    

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23. © Black Inc.
    Stateful and asynchronous events
    select {
    }
    case case case case State A
    select {
    }
    case case case case State D
    select {
    }
    case case case case State B
    select {
    }
    case case case case State C
    23
    

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24. © Black Inc.
    Why Go, How Go?
    ● Go provides good asynchronous event handling
    ○ Goroutine and Channel
    ○ Handling async events with `select` statement
    ● Good debugging for asynchronous
    ○ built-in race detector
    ○ built-in goroutine profiler (pprof)
    24
    

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25. © Black Inc.
    Video streaming
    

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26. © Black Inc.
    Player Gaming Server
    Player Action
    Video Streaming
    26
    

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27. © Black Inc.
    How to deliver low-latency video?
    ● low-latency streaming
    ● peer-to-peer (P2P) connection
    ● standardization by W3C and IETF
    ● media processing (video/audio)
    ● free and open-source
    27
    

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28. © Black Inc.
    How to deliver low-latency video?
    Player
    X11
    Game
    PulseAudio
    Capturing frame
    and encoding
    Peering and
    streaming media
    28
    

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29. © Black Inc.
    What language?
    29
    https://en.wikipedia.org/wiki/GStreamer
    

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30. © Black Inc.
    What language?
    30
    https://en.wikipedia.org/wiki/GStreamer https://en.wikipedia.org/wiki/WebRTC
    

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31. © Black Inc.
    go-gst
    ● https://github.com/tinyzimmer/go-gst
    ● Gstreamer bindings and utilities for golang
    ● Using CGO
    31
    

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32. © Black Inc.
    Pion WebRTC
    ● https://github.com/pion/webrtc
    ● A Pure Go implementation of WebRTC API
    32
    

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33. © Black Inc.
    Why Go, How Go?
    ● We use gstreamer and WebRTC for video streaming
    ○ Both of them have Go libraries!
    33
    

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34. © Black Inc.
    Cloud Native
    Infrastructure
    

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35. © Black Inc.
    Cloud Native Infrastructure
    ● Multi services, multi containers
    ● Immutable infrastructure
    ● Using managed service in public cloud
    35
    

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36. © Black Inc.
    Cloud providers
    support
    

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37. © Black Inc.
    gocloud
    ● https://github.com/google/go-cloud
    ● Abstraction layer for cloud providers
    ○ Amazon, Azure, Google, …
    ○ Local environment support
    ● Storage, KVS, DB, PubSub, Secrets, ...
    37
    

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38. © Black Inc.
    gocloud
    38
    import (
    "gocloud.dev/blob"
    _ "gocloud.dev/blob/fileblob"
    )
    import (
    "gocloud.dev/blob"
    _ "gocloud.dev/blob/gcsblob"
    )
    Local Google Cloud
    

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39. © Black Inc.
    Build and Deploy
    

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40. © Black Inc.
    Build and Deploy
    How do we build and deploy game servers?
    40
    

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41. © Black Inc.
    Build and Deploy
    How do we build and deploy game servers?
    Build Deploy
    41
    

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42. © Black Inc.
    ko
    ● https://github.com/google/ko
    ● container image builder for Go applications
    42
    

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43. © Black Inc.
    Without ko
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    $ docker build -t gcr.io/...
    $ docker push gcr.io/...
    43
    Writing Dockerfile per container
    

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44. © Black Inc.
    Without ko
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    44
    service A
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    service B
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    service C
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    service D, ...
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    😅
    

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45. © Black Inc.
    With ko
    FROM golang as builder
    RUN CGO_ENABLED=0 go build ...
    FROM scratch
    COPY --from=builder ...
    $ ko publish ./src/app
    => gcr.io/...
    $ docker build -t gcr.io/...
    $ docker push gcr.io/...
    45
    Go package path
    

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46. © Black Inc.
    Deploying game servers
    46
    apiVersion: "agones.dev/v1"
    kind: Fleet
    spec:
    template:
    spec:
    template:
    spec:
    containers:
    - name: agent
    image: ko://path/to/... kustomize
    apply YAML
    replace the image
    

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47. © Black Inc.
    go-task
    ● https://github.com/go-task/task
    ● simpler GNU Make alternative written in Go
    ● We use go-task as a task runner
    ○ build
    ○ deploy
    ○ code generation
    ○ ...
    47
    

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48. © Black Inc.
    go-task
    $ task deploy:serviceA-local
    $ task deploy:serviceA-dev
    $ task deploy:serviceA-prd
    48
    common deploy
    task
    local
    variables
    dev
    variables
    ...
    ● YAML-based
    ● flexible variables
    

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49. © Black Inc.
    Conclusion
    

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50. © Black Inc.
    Conclusion
    ● Go is well suited for cloud gaming platform development
    ○ features for writing stateful servers
    ○ bindings of media frameworks (gstreamer, WebRTC)
    ● Many of the tools for Cloud Native are powered by Go
    50
    … and more!
    

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51. © Black Inc.
    Cloud Gaming Platform
    with Go
    castaneai
    Backend engineer
    Black Inc.
    

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