feat: implement real time update server on top of web sockets

Closes: #2

Add backend server that is able to connect to Kubernetes `controller-runtime`
and fetch data from it and send updates to the JS frontend through a web socket.

As we have pretty similar implementation of `controller-runtime` in Talos all
communication with K8s runtime is done through an abstraction layer.

Potentially, we should get exactly the same interface for Talos resource
watch.

WebSocket protocol is currently used for all client-server
communication, but later on we may decide to add REST RPC calls as well.
Mainly for Talos API calls.

UI is still more of a draft, but it is possible to get updated list of
pods, nodes, namespaces, deployments, daemonsets.

Signed-off-by: Artem Chernyshev <artem.0xD2@gmail.com>

.babelrc

@@ -1,6 +1,6 @@
 // THIS FILE WAS AUTOMATICALLY GENERATED, PLEASE DO NOT EDIT.
 //
-// Generated on 2021-03-30T15:37:32Z by kres def665a-dirty.
+// Generated on 2021-04-02T18:16:15Z by kres 957c8d9-dirty.
 
 module.exports = {
   presets: [

.jestrc

@@ -1,6 +1,6 @@
 // THIS FILE WAS AUTOMATICALLY GENERATED, PLEASE DO NOT EDIT.
 //
-// Generated on 2021-03-30T15:37:32Z by kres def665a-dirty.
+// Generated on 2021-04-02T18:16:15Z by kres 957c8d9-dirty.
 
 module.exports = {
   preset: '@vue/cli-plugin-unit-jest/presets/typescript-and-babel/',

.tsconfig

@@ -1,6 +1,6 @@
 {  
   "compilerOptions": {
-		"baseUrl": "./",
+    "baseUrl": "./",
     "experimentalDecorators": true,
     "strict": true,
     "moduleResolution": "node",

Dockerfile

@@ -2,7 +2,7 @@
 
 # THIS FILE WAS AUTOMATICALLY GENERATED, PLEASE DO NOT EDIT.
 #
-# Generated on 2021-03-30T15:28:27Z by kres def665a-dirty.
+# Generated on 2021-04-02T18:16:15Z by kres 957c8d9-dirty.
 
 ARG JS_TOOLCHAIN
 ARG TOOLCHAIN
@@ -45,6 +45,8 @@ COPY .tsconfig ./tsconfig.json
 COPY ./frontend/src ./src
 COPY ./frontend/tests ./tests
 COPY ./frontend/public ./public
+COPY ./frontend/postcss.config.js ./postcss.config.js
+COPY ./frontend/tailwind.config.js ./tailwind.config.js
 
 # build tools
 FROM toolchain AS tools

cmd/theila/main.go

@@ -5,57 +5,55 @@
 package main
 
 import (
-	"fmt"
-	"io/fs"
+	"context"
+	"errors"
 	"log"
 	"net/http"
+	"os/signal"
+	"syscall"
 
-	"github.com/go-chi/chi"
-	"github.com/go-chi/chi/middleware"
+	"github.com/spf13/cobra"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 
-	"github.com/talos-systems/theila/internal/frontend"
+	"github.com/talos-systems/theila/internal/backend"
+	"github.com/talos-systems/theila/internal/backend/logging"
 )
 
-func main() {
-	log.Println("Starting app")
-
-	router := registerRoutes()
-
-	port := 8080
-
-	log.Printf("Serving on port %d", port)
-
-	if err := http.ListenAndServe(fmt.Sprintf("0.0.0.0:%d", port), router); err != nil {
-		log.Fatal(err)
-	}
+// rootCmd represents the base command when called without any subcommands.
+var rootCmd = &cobra.Command{
+	Use:   "theila",
+	Short: "Talos and Sidero frontend",
+	Long:  ``,
 }
 
-func registerRoutes() http.Handler {
-	log.Println("Registering routes")
-
-	r := chi.NewMux()
+var rootCmdArgs struct {
+	address string
+	port    int
+}
 
-	r.Use(middleware.Logger)
-	r.Use(middleware.Recoverer)
+func main() {
+	config := zap.NewDevelopmentConfig()
+	config.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
 
-	sub, err := fs.Sub(frontend.Dist, "dist")
+	zapLogger, err := config.Build()
 	if err != nil {
-		log.Fatalf("failed to get dist/frontend directory")
+		log.Fatalf("failed to set up logging %s", err)
 	}
 
-	r.Handle("/*", http.FileServer(http.FS(sub)))
+	logger := zapLogger.Sugar()
+	logging.Logger = logger
 
-	logRoutes(r)
+	server := backend.NewServer(rootCmdArgs.address, rootCmdArgs.port)
 
-	return r
-}
+	ctx, _ := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 
-func logRoutes(r chi.Routes) {
-	log.Println("Serving with routes:")
-	//nolint:errcheck
-	chi.Walk(r, func(method, route string, handler http.Handler, middlewares ...func(http.Handler) http.Handler) error {
-		log.Printf("\t%s %s", method, route)
+	if err := server.Run(ctx); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		logger.Fatalf("failed to run server %s", err)
+	}
+}
 
-		return nil
-	})
+func init() {
+	rootCmd.Flags().IntVarP(&rootCmdArgs.port, "port", "p", 8080, "Start HTTP server on the defined port.")
+	rootCmd.Flags().StringVar(&rootCmdArgs.address, "address", "", "Start HTTP server on the defined address.")
 }