web

Documentation

Overview

Package web contains a small web framework extension.

Index

• func AddSpan(ctx context.Context, spanName string, keyValues ...attribute.KeyValue) (context.Context, trace.Span)
• func Decode(r *http.Request, val any) error
• func GetTime(ctx context.Context) time.Time
• func GetTraceID(ctx context.Context) string
• func IsShutdown(err error) bool
• func NewShutdownError(message string) error
• func Param(r *http.Request, key string) string
• func Respond(ctx context.Context, w http.ResponseWriter, data any, statusCode int) error
• type App
  • func NewApp(shutdown chan os.Signal, tracer trace.Tracer, mw ...MidHandler) *App
  • func (a *App) EnableCORS(mw MidHandler)
  • func (a *App) Handle(method string, group string, path string, handler Handler, mw ...MidHandler)
  • func (a *App) HandleNoMiddleware(method string, group string, path string, handler Handler)
  • func (a *App) ServeHTTP(w http.ResponseWriter, r *http.Request)
  • func (a *App) SignalShutdown()
• type Handler
• type MidHandler
• type Values
  • func GetValues(ctx context.Context) *Values

Functions

func AddSpan

func AddSpan(ctx context.Context, spanName string, keyValues ...attribute.KeyValue) (context.Context, trace.Span)

AddSpan adds a OpenTelemetry span to the trace and context.

func Decode

func Decode(r *http.Request, val any) error

Decode reads the body of an HTTP request looking for a JSON document. The body is decoded into the provided value. If the provided value is a struct then it is checked for validation tags. If the value implements a validate function, it is executed.

func GetTime

func GetTime(ctx context.Context) time.Time

GetTime returns the time from the context.

func GetTraceID

func GetTraceID(ctx context.Context) string

GetTraceID returns the trace id from the context.

func IsShutdown

func IsShutdown(err error) bool

IsShutdown checks to see if the shutdown error is contained in the specified error value.

func NewShutdownError

func NewShutdownError(message string) error

NewShutdownError returns an error that causes the framework to signal a graceful shutdown.

func Param

func Param(r *http.Request, key string) string

Param returns the web call parameters from the request.

func Respond

func Respond(ctx context.Context, w http.ResponseWriter, data any, statusCode int) error

Respond converts a Go value to JSON and sends it to the client.

Types

type App

type App struct {
	// contains filtered or unexported fields
}

App is the entrypoint into our application and what configures our context object for each of our http handlers. Feel free to add any configuration data/logic on this App struct.

func NewApp

func NewApp(shutdown chan os.Signal, tracer trace.Tracer, mw ...MidHandler) *App

NewApp creates an App value that handle a set of routes for the application.

func (*App) EnableCORS

func (a *App) EnableCORS(mw MidHandler)

EnableCORS enables CORS preflight requests to work in the middleware. It prevents the MethodNotAllowedHandler from being called. This must be enabled for the CORS middleware to work.

func (*App) Handle

func (a *App) Handle(method string, group string, path string, handler Handler, mw ...MidHandler)

Handle sets a handler function for a given HTTP method and path pair to the application server mux.

func (*App) HandleNoMiddleware

func (a *App) HandleNoMiddleware(method string, group string, path string, handler Handler)

HandleNoMiddleware sets a handler function for a given HTTP method and path pair to the application server mux. Does not include the application middleware or OTEL tracing.

func (*App) ServeHTTP

func (a *App) ServeHTTP(w http.ResponseWriter, r *http.Request)

ServeHTTP implements the http.Handler interface. It's the entry point for all http traffic and allows the opentelemetry mux to run first to handle tracing. The opentelemetry mux then calls the application mux to handle application traffic. This was set up on line 44 in the NewApp function.

func (*App) SignalShutdown

func (a *App) SignalShutdown()

SignalShutdown is used to gracefully shut down the app when an integrity issue is identified.

type Handler

type Handler func(ctx context.Context, w http.ResponseWriter, r *http.Request) error

A Handler is a type that handles a http request within our own little mini framework.

type MidHandler

type MidHandler func(Handler) Handler

MidHandler is a handler function designed to run code before and/or after another Handler. It is designed to remove boilerplate or other concerns not direct to any given app Handler.

type Values

type Values struct {
	TraceID    string
	Tracer     trace.Tracer
	Now        time.Time
	StatusCode int
}

Values represent state for each request.

func GetValues

func GetValues(ctx context.Context) *Values

GetValues returns the values from the context.