feat(embed): make authelia embedable (#8841)

This adds a highly experimental option for developers looking to embed Authelia within another go binary.

Closes #5803

Signed-off-by: James Elliott <james-d-elliott@users.noreply.github.com>

1 files changed, 120 insertions, 0 deletions

diff --git a/internal/service/server.go b/internal/service/server.go
new file mode 100644
index 000000000..15921af01
--- /dev/null
+++ b/internal/service/server.go
@@ -0,0 +1,120 @@
+package service
+
+import (
+	"context"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	"github.com/valyala/fasthttp"
+
+	"github.com/authelia/authelia/v4/internal/server"
+)
+
+func ProvisionServer(ctx Context) (service Provider, err error) {
+	var (
+		s        *fasthttp.Server
+		listener net.Listener
+		paths    []string
+		isTLS    bool
+	)
+
+	switch s, listener, paths, isTLS, err = server.New(ctx.GetConfiguration(), ctx.GetProviders()); {
+	case err != nil:
+		return nil, err
+	case s != nil && listener != nil:
+		service = NewBaseServer("main", s, listener, paths, isTLS, ctx.GetLogger())
+	default:
+		return nil, nil
+	}
+
+	return service, nil
+}
+
+func ProvisionServerMetrics(ctx Context) (service Provider, err error) {
+	var (
+		s        *fasthttp.Server
+		listener net.Listener
+		paths    []string
+		isTLS    bool
+	)
+
+	switch s, listener, paths, isTLS, err = server.NewMetrics(ctx.GetConfiguration(), ctx.GetProviders()); {
+	case err != nil:
+		return nil, err
+	case s != nil && listener != nil:
+		service = NewBaseServer("metrics", s, listener, paths, isTLS, ctx.GetLogger())
+	default:
+		return nil, nil
+	}
+
+	return service, nil
+}
+
+// NewBaseServer creates a new Server with the appropriate logger etc.
+func NewBaseServer(name string, server *fasthttp.Server, listener net.Listener, paths []string, isTLS bool, log *logrus.Entry) (service *Server) {
+	return &Server{
+		name:     name,
+		server:   server,
+		listener: listener,
+		paths:    paths,
+		isTLS:    isTLS,
+		log:      log.WithFields(map[string]any{logFieldService: serviceTypeServer, serviceTypeServer: name}),
+	}
+}
+
+// Server is a Provider which runs a web server.
+type Server struct {
+	name     string
+	server   *fasthttp.Server
+	paths    []string
+	isTLS    bool
+	listener net.Listener
+	log      *logrus.Entry
+}
+
+// ServiceType returns the service type for this service, which is always 'server'.
+func (service *Server) ServiceType() string {
+	return serviceTypeServer
+}
+
+// ServiceName returns the individual name for this service.
+func (service *Server) ServiceName() string {
+	return service.name
+}
+
+// Run the Server.
+func (service *Server) Run() (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			service.log.WithError(recoverErr(r)).Error("Critical error caught (recovered)")
+		}
+	}()
+
+	service.log.Infof(fmtLogServerListening, connectionType(service.isTLS), service.listener.Addr().String(), strings.Join(service.paths, "' and '"))
+
+	if err = service.server.Serve(service.listener); err != nil {
+		service.log.WithError(err).Error("Error returned attempting to serve requests")
+
+		return err
+	}
+
+	return nil
+}
+
+// Shutdown the Server.
+func (service *Server) Shutdown() {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+
+	defer cancel()
+
+	if err := service.server.ShutdownWithContext(ctx); err != nil {
+		service.log.WithError(err).Error("Error occurred during shutdown")
+	}
+}
+
+// Log returns the *logrus.Entry of the Server.
+func (service *Server) Log() *logrus.Entry {
+	return service.log
+}