API Startup Flow Chart

Main entrypoint

The OpenAPI spec can be passed to the CLI via environment variable WEOS_SCHEMA or as a command line argument schema. The value for the OpenAPI spec could be the contents of a valid spec or the filepath to the specification

Instantiate API

The api is instantiated calling api.New(). The openapi spec is passed to the api.New() function as a file path or as a string. The api.New() function instantiates the echo framework and then initializes the api. An instance of the api is returned and the api instance is essentially a service container that can be used to access other services.

flowchart TD
    Start --> newEcho[Instantiate Echo] --> initialize[[Initialize API]] --> initResponse{Successfully\nInitialized}
    initResponse -->|Yes| run([API Running])
    initResponse -->|No| logError[Log Error] --> fail([API Not Running])

For a quick start you can use api.Start() instead of api.New()

Initialize API

During the initialization of the api the following steps are performed:

1. Setup default logger, http client in service container
2. Register standard controllers
3. Register standard middleware
4. Register standard global initializers
5. Register standard operation initializers
6. Setup the default command dispatcher
7. Setup global middleware
8. Run global initializers
9. Run path initializers
10. Run operation initializers

flowchart TD
    Start --> setupDefaultServices[Set Logger, Http Client] --> registerBasicControllers[Setup Default Controllers] --> registerMiddleawre[Register Middleware]
    registerMiddleawre --> registerGlobalInitializers[Register Global Initializers] --> registerPathInitializers[Register Path Initializers] --> registerOperationInitializers[Register Operation Initializers] --> registerCommandDispatcher[Register Command Dispatcher] --> registerGlobalMiddleware[Register Global Middleware] --> runGlobalInitializers[Run Global Initializers] --> runPathInitializers[Run Path Initializers] --> runOperationInitializers[Run Operation Initializers] --> runGlobalMiddleware[Run Global Middleware] --> runPathMiddleware[Run Path Middleware] --> runOperationMiddleware[Run Operation Middleware] --> runOperation[Run Operation] --> End

Process WeOS Config

The x-weos-config contains the database configuration that is used to instantiate a database connection. It also contains REST middleware configuration

flowchart TD
    Start --> initializeService[[Initialize Service]] --> hasPreMiddleware{Has\nUnprocessed\nMiddleware}
    hasPreMiddleware -->|Yes| checkMiddlewareIsValid[Check Middleware Is Valid] --> isValidMiddlware{Is Valid}
    hasPreMiddleware -->|No| End
    isValidMiddlware --> |Yes| addToEcho[Add to echo pre middleware] --> End
    isValidMiddlware --> |No| End

Initialize Service

Each API extends a base Service that WeOS provides. When a service is instantiated the db connections are setup using database configuration in the x-weos-config

flowchart LR
    Start --> intantiateGorm[Intantiate Gorm] --> setupHTTPClient[Setup HTTPClient] --> setupEventStream[Setup Event Repository] --> BaseService[/Base Service/] --> End([End]) 

Setup Paths

Each path in the OpenAPI spec is processed and the relevant middleware, controllers are associated

flowchart TD
    Start --> paths[/Paths/] --> unprocessedPaths{Has\nUnprocessed\nPaths}
    unprocessedPaths -->|Yes|unprocessedOperations{Has\nUnprocessed\nOperations}
    unprocessedOperations -->|Yes|unprocessedMiddleware{Has\nUnprocessed\nMiddleware}
    unprocessedMiddleware -->|Yes|getMiddleware[Get Middleare]-->middlewareExists{Middleware Exists}
    middlewareExists-->|No|controllerSpecified{Controller Specified}
    middlewareExists-->|Yes|addToPath[Add to Path Middlware List]-->controllerSpecified
    unprocessedMiddleware -->|No|controllerSpecified
    controllerSpecified-->|Yes|getController{Controller\nValid}
    getController-->|Yes|setController
    controllerSpecified-->|No|canUseStandardController{Has\nStandard\nController}
    canUseStandardController-->|Yes|standardController[/Standard Controller/]-->setController
    canUseStandardController-->|No|setController
    setController-->hasController{Has\nController}
    hasController-->|Yes|configureEchoRoute[Configure Echo Route]-->configureCORS[Configure CORS]-->echoInstance[/echo instance/]-->End([End])
    hasController-->|No|logError[Log Error]-->configureCORS