聊聊dapr的Pipeline

import (
    "github.com/dapr/dapr/pkg/config"
    "github.com/valyala/fasthttp"
)

type Middleware func(h fasthttp.RequestHandler) fasthttp.RequestHandler

// HTTPPipeline defines the middleware pipeline to be plugged into Dapr sidecar
type Pipeline struct {
    Handlers []Middleware
}

func BuildHTTPPipeline(spec config.PipelineSpec) (Pipeline, error) {
    return Pipeline{}, nil
}

func (p Pipeline) Apply(handler fasthttp.RequestHandler) fasthttp.RequestHandler {
    for i := len(p.Handlers) - 1; i >= 0; i-- {
        handler = p.Handlers[i](handler)
    }
    return handler
}

type server struct {
    config      ServerConfig
    tracingSpec config.TracingSpec
    metricSpec  config.MetricSpec
    pipeline    http_middleware.Pipeline
    api         API
}

func (s *server) useComponents(next fasthttp.RequestHandler) fasthttp.RequestHandler {
    return s.pipeline.Apply(next)
}