emissary/internal/agent/controller/proxy/reverse_proxy.go

package proxy

import (
	"context"
	"net/http"
	"sync"

	"forge.cadoles.com/Cadoles/emissary/internal/proxy"
	"github.com/getsentry/sentry-go"
	"github.com/pkg/errors"
	"gitlab.com/wpetit/goweb/logger"
)

type ReverseProxy struct {
	addr   string
	server *http.Server
	mutex  sync.RWMutex
}

func (p *ReverseProxy) Start(ctx context.Context, addr string, funcs ...proxy.OptionFunc) error {
	if p.server != nil {
		if err := p.Stop(); err != nil {
			return errors.WithStack(err)
		}
	}

	server := &http.Server{
		Addr: addr,
	}

	proxy := proxy.New(funcs...)
	server.Handler = proxy

	p.mutex.Lock()
	p.server = server
	p.addr = addr
	p.mutex.Unlock()

	go func() {
		defer func() {
			if err := p.Stop(); err != nil {
				err = errors.WithStack(err)
				logger.Error(ctx, "error while stopping gateway", logger.E(err))
				sentry.CaptureException(err)
			}
		}()

		if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			err = errors.WithStack(err)
			logger.Error(ctx, "error while listening", logger.E(err))
			sentry.CaptureException(err)
		}
	}()

	return nil
}

func (p *ReverseProxy) Running() bool {
	p.mutex.RLock()
	defer p.mutex.RUnlock()

	return p.server != nil
}

func (p *ReverseProxy) Stop() error {
	p.mutex.Lock()
	defer p.mutex.Unlock()

	if p.server == nil {
		return nil
	}

	if err := p.server.Close(); err != nil && !errors.Is(err, http.ErrServerClosed) {
		return errors.WithStack(err)
	}

	p.server = nil

	return nil
}

func NewReverseProxy() *ReverseProxy {
	return &ReverseProxy{}
}