add web client - future plans for loading screen during refresh

main.go

@@ -3,15 +3,19 @@ package main
 import (
 	"log"
 	"os"
+	"sync"
+	"text/template"
 	"time"
 
 	"deadbeef.codes/steven/ynab-portfolio-monitor/ynab"
 )
 
 var (
-	configuredProviders []AccountProvider // Any account providers that are successfully configured get added to this slice
-	ynabClient          *ynab.Client      // YNAB HTTP client
-	lastRefresh         time.Time
+	configuredProviders []AccountProvider  // Any account providers that are successfully configured get added to this slice
+	ynabClient          *ynab.Client       // YNAB HTTP client
+	lastRefresh         time.Time          // Timestamp that last data refresh ran - used for rate limiting
+	refreshRunning      *sync.Mutex        // True if a refresh is currently running
+	t                   *template.Template // HTML templates in the templates directory
 )
 
 // Called at program startup or if SIGHUP is received
@@ -49,6 +53,13 @@ func init() {
 	if err != nil {
 		log.Fatalf("failed to create ynab client: %v", err)
 	}
+
+	// Web Templates
+	// Parse all template files at startup
+	t, err = template.ParseGlob("./templates/*")
+	if err != nil {
+		log.Fatalf("couldn't parse HTML templates: %v", err)
+	}
 }
 
 func main() {
@@ -62,10 +73,13 @@ func main() {
 }
 
 func refreshData() {
+	refreshRunning.Lock()
+	defer refreshRunning.Unlock()
 
 	// Only allow a refresh at most once every 5 minutes
 	if time.Now().Before(lastRefresh.Add(time.Minute * 5)) {
 		log.Printf("refresh rate limited")
+
 		return
 	}
 	lastRefresh = time.Now()