Go Backends for frontends with GraphQL and gRPC

Transcript

1. Go Backends for Frontends
   with and
   @__timakin__
   

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2. Seiji Takahashi
   Software Engineer
   Gunosy Inc. Tokyo, Japan.
   

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3. BFF
   

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4. Backends
   For
   Frontends
   

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5. BFF
   (Web)
   BFF
   (Native)
   User
   Micro Service
   Article
   Micro Service
   Payment
   Micro Service
   Access Controled
   Web Browser
   iOS/Android
   

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6. Pros of BFF
   ● Each microservices can focus on only their own
   responsibility.
   ● Customize networking protocol for each clients.
   ● Flexibly change the response fields.
   

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7. BFF Use-cases
   1. API Aggregation
   2. Session Management
   3. SSR
   4. File Upload
   5. WebSocket
   

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8. BFF Use-cases
   1. API Aggregation
   BFF
   User
   Micro Service
   Article
   Micro Service
   Comment
   Micro Service
   Client
   Concat every JSON Object
   from internal APIs
   Send requests to several
   services concurrently
   Request an
   article entity
   

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9. BFF Use-cases
   2. Session Management
   BFF
   User
   Micro Service
   Article
   Micro Service
   Comment
   Micro Service
   Client
   Send requests with
   token
   Get data from
   session store
   Send session_id
   Session
   Store
   

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10. Page request
    BFF Use-cases
    3. SSR
    BFF
    User
    Micro Service
    Article
    Micro Service
    Comment
    Micro Service
    Client
    Concat every JSON and pass
    them to HTML renderer
    Data fetching
    

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11. Chunked file upload
    BFF Use-cases
    4. File Upload
    BFF
    External
    File
    Storage
    Internal API
    Client
    Send a request with filePath
    Store file
    

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12. Connect with WS
    BFF Use-cases
    5. WebSocket/Polling
    BFF
    Message
    Queue
    Internal API
    Client
    Pub/Sub
    

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13. Micro Service
    Today’s CaseStudy
    BFF
    Micro Service
    Micro Service
    Web Client
    

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14. ● When they talk about BFF…
    ○ JavaScript(Node) is popular in most of the cases.
    ○ Because it eases the communication between
    frontend & backend engineers.
    BFF in Go
    

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15. ● Why Go?
    ○ If you are a backend engineer, Go BFF will be a good choice
    from the aspect of performance.
    ○ With goroutine, Go would handle the concurrent internal
    accesses rapidly.
    ■ If you threw away REST and changed into RPC-call,
    you must send request multiple servers everytime.
    ■ This means internal latency is critical for UX.
    ○ Awesome packages for both of GraphQL and gRPC exist in
    Go community.
    BFF in Go
    

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16. GraphQL
    

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17. ● GraphQL is a simple query
    language for API which has the
    type system.
    ● Instead of JSON request in like
    REST API or JSON-RPC, you will
    send `query` to GraphQL server.
    ● Implementation in JavaScript is
    the most active.
    GraphQL introduction
    

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18. Client
    

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19. GraphQL vs gRPC
    ● Generally, GraphQL is
    hotter than gRPC.
    ● In a lot of countries
    GraphQL wins.
    ● However, in East
    Asia(especially in China),
    gRPC has more fans.
    

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20. ● Client-side-related words
    like `apollo`, `react`.
    ● `github` is ranked in the top
    10.
    Related words of each protocols
    ● Server-side languages like
    `java` , `goland`, `python`
    and the format `protobuf`.
    

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21. ● In-browser playground
    to explore GraphQL
    calls.
    GraphiQL
    

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22. ● Packages
    ○ graphql-go/graphql
    ○ graphql-go/relay
    ○ samsarahq/thunder
    ○ 99designs/gqlgen
    GraphQL in Go
    

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23. ● Packages
    ○ graphql-go/graphql
    ○ graphql-go/relay
    ○ samsarahq/thunder
    ○ 99designs/gqlgen
    GraphQL in Go
    

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24. ● github.com/99designs/gqlgen
    ○ Active development
    ○ Type-Safe
    ○ Schema Driven
    ○ Custom middleware appendable
    GraphQL in Go
    

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25. ● github.com/99designs/gqlgen
    ○ Active development
    ○ Type-Safe
    ○ Schema Driven
    ○ Custom middleware appendable
    GraphQL in Go
    

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26. ● github.com/99designs/gqlgen-contrib
    ○ package of middlewares for performance tracing
    ■ apollo-tracing
    ■ opencensus
    ● datadog
    ■ opentracing
    ■ prometheus
    GraphQL in Go
    

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27. GraphQL in Go
    ● Other packages
    ○ Cannot share schema with frontend
    ○ Reflection based schema
    ■ A negative effect to latency
    

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28. schema.graphql
    Prepare schemas
    Instead of
    auto-generated code,
    you can use defined
    structs.
    gqlgen.yml
    

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29. $ gqlgen
    Code generate
    

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30. The implementation inside functions
    are not automatically generated.
    Write your own code.
    grpc client
    

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31. When you test GraphQL
    ● Integration test with input & golden files.
    ○ Record a real request and response
    ○ Mock or temporarily boot internal API
    ○ Iterate recorded files and check the equality with
    the actual responses
    

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32. gRPC
    

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33. ● HTTP/2 networking
    ● Protobuf serialization
    ○ template code generation
    ● Go is one of the most active languages for gRPC
    implementation.
    ● Number of Github stars
    ○ Go > Java > Node > Swift > PHP > Haskell
    

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34. ● github.com/golang/protobuf/proto
    ● github.com/golang/protobuf/protoc-gen-go
    ● google.golang.org/grpc
    Required packages
    ● github.com/ktr0731/evans
    ● github.com/uber/prototool
    Optional tools
    

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35. blog.proto
    Schema
    

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36. uber/prototool strictly checks and formats *.proto
    Linter
    

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37. Linter
    Define the rules on prototool.yaml
    Run commands
    

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38. Code Generation
    github.com/golang/protobuf/protoc-gen-go
    

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39. Client
    

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40. Client
    send a request to internal gRPC API
    

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41. Server
    

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42. Server
    

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43. Server
    Call the logic implemented by yourself
    e.g. DB access, external API-call
    

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44. After implementation
    ktr0731/evans helps you to explore your gRPC server locally
    

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45. Conclusion
    ● Go is one of the best candidate language for BFF.
    ● GraphQL + gRPC will empower you with
    schema-driven-development and low-latency
    protocol.
    

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46. Thank you for listening
    

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