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Go Package Layout

Broadly speaking, it is divided into 3 main package folders

  • cmd contains main program
  • internal app business logic
  • pkg for packages that can be imported by other go projects / repos

Service Package Design​

user_service_repo
    cmd/ <- boleh import package /internal & /pkg
        api/ <- bisa run echo http & grpc di port yg sama, run /internal/{grpc,http}
            main.go
        pubsubworker/ <- bisa run multiple pubsub subscription worker, run /internal/worker
            main.go
    internal/ <-- boleh import /pkg, tidak boleh diimport secara go-module dari repo luar
        service/ <- boleh import repository, api_client, tidak boleh import /internal/http & internal/grpc
            user_password_service.go
            ...
            service.go
        http/ <- expose /internal/service functions. Request/response body struct define di /pkg/http
            handler/
                user_password_handler.go
                ...
                handler.go
            my_custom_middleware.go
            my_custom2_middleware.go
            ...
            server.go
        grpc/ <- expose /internal/service functions
            user_password_handler.go
            server.go
        worker/ <- import repository, api_client
            pubsub_worker.go
            user_updated_event_worker.go
            new_oba_created_event_worker.go
            ...
        repository/ <- group by datasource / host url instance
            userpostgres/ <- should be generated from sqlc
                user_password_query.sql.go
                user_profile_query.sql.go
                ...
            marketplacepostgres/ <- also should be generated from sqlc
                user_email.sql.go
                user_address.sql.go
                ...
            registrationmongo/
                user_registration_repository.go
                ...
            membermongo/
                officer_attribute_repository.go
                ...
            redis/
                redis_repository.go
                user_cart_repository.go
                ...
            sessionredis/
                redis_repository.go
                user_session_repository.go
                ...
            ...
        config/
            config_keys.go <- define constant config keys here
            config.go <- contains httpClient, db, redis or pubsub connection
            constructor
        ...
    pkg/ <- tidak boleh import /internal, boleh diimport secara gomodule dari repo luar
        pb/
            user.proto
            user.pb.go <-- generated
            user_validation.go
            ...
        http/
            http_api_request.go
            http_api_response.go
            http_api_client.go
        ...

Package Descriptions​

  1. /cmd
  • /cmd/api/main.go -> run gRPC & echo HTTP on the same runtime, different ports. Or choose one as needed. But don't make 2 main programs for gRPC & http unless absolutely necessary for scaling / traffic problems tall.
  • /cmd/pubsubworker/main.go -> run pubsub subscription worker. Can subscribe multiple subscriptions at the same time (with different goroutines). No need to create main programs for different workers unless necessary for scaling / high throughput problems.

The point is, we avoid premature-optimization & make the program more maintainable in terms of development, deployment & operation.

  1. /internal

internal packages for program logic needed internally by services, and not intended to be imported by other go programs by gomodule.

  • /internal/service core logic of application gRPC api / JSON webservice
  • /internal/http implementation of echo.Echo http server, router & handler (if required). Implement refer to echo HTTP API design
  • /internal/worker logic for GCP Pubsub / other messaging.
  • /internal/repository data access layer logic. Implementation refer to
  • repository design
  • /internal/apiclient logic regarding data access via API to third party systems third. Can pass http JSON API, SOAP, gRPC etc.
  • /internal/config contains constant config keys, constructor of dependency services.
  1. /pkg
  • /pkg/pb contains definition of .proto file, generated .pb.go, & validation protobuff struct
  • /pkg/http contains the definition of the request/response body (go/json struct). Can also include api-client if needed (remember, communication between internal services use gRPC)

Reference​