From 31ffadd2cfb20c05984fd9b73f3a179409b7c735 Mon Sep 17 00:00:00 2001
From: Mike Shoup <mike@shoup.io>
Date: Sun, 30 Sep 2018 12:24:00 -0600
Subject: [PATCH] Add web server

---
 web.go | 53 +++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 49 insertions(+), 4 deletions(-)

diff --git a/web.go b/web.go
index 489bd25..f3c4a2a 100644
--- a/web.go
+++ b/web.go
@@ -1,13 +1,36 @@
 package main
 
 import (
+	"context"
+	"log"
+	"net/http"
 	"sync"
+	"time"
+
+	"github.com/gin-gonic/gin"
 )
 
-// RunWeb launches a web server
-func RunWeb(sc <-chan State, done <-chan bool, wg *sync.WaitGroup) {
-	states := make(map[string]State)
+// PingHandler responds to get requests with the message "pong".
+func PingHandler(c *gin.Context) {
+	c.String(http.StatusOK, "pong")
+}
 
+// SetupRouter initializes the gin router.
+func SetupRouter() *gin.Engine {
+	r := gin.Default()
+
+	gin.SetMode(gin.ReleaseMode)
+
+	// Ping
+	r.GET("/ping", PingHandler)
+
+	return r
+}
+
+// RunWeb launches a web server. sc is used to update the states from the Thermostats.
+func RunWeb(sc <-chan State, done <-chan bool, wg *sync.WaitGroup) {
+	// Update sensor states when a new state comes back from the thermostat.
+	states := make(map[string]State)
 	go func() {
 		for {
 			s := <-sc
@@ -15,7 +38,29 @@ func RunWeb(sc <-chan State, done <-chan bool, wg *sync.WaitGroup) {
 		}
 	}()
 
-	<-done
+	// Launch the web server
+	r := SetupRouter()
+	srv := &http.Server{
+		Addr:    ":8080",
+		Handler: r,
+	}
 
+	go func() {
+		// service connections
+		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Fatalf("listen: %s\n", err)
+		}
+	}()
+
+	// Wait for the done signal
+	<-done
+	log.Println("Shutdown Server ...")
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	if err := srv.Shutdown(ctx); err != nil {
+		log.Fatal("Server Shutdown:", err)
+	}
+	log.Println("Server exiting")
 	wg.Done()
 }