attempted fix of race condition

slideshow.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bufio"
 	"fmt"
 	"log"
 	"os/exec"
@@ -12,22 +13,31 @@ func slideshow(ch <-chan string) {
 	ticker := time.NewTicker(time.Duration(config.Duration) * time.Minute)
 
 	//set a flat background color based on config defaults
-	fillReady := make(chan bool)
-	go func() {
 	fillCmd := exec.Command("swaybg", "-c", "#232136")
+	stdout, _ := fillCmd.StdoutPipe()
+	scanner := bufio.NewScanner(stdout)
+	out := make(chan string)
+	go func() {
+		for scanner.Scan() {
+			out <- scanner.Text()
+		}
+	}()
+
+	ready := make(chan bool)
+	go func() {
 		err := fillCmd.Start()
 		if err != nil {
 			fmt.Println("could not set background color", err)
 		}
+		<-out
+		ready <- true
 		fmt.Println("bg color set!")
-		fillReady <- true
 		fillCmd.Wait()
 	}()
 
 	var cmd *exec.Cmd
 	go func() {
 		for {
-			<-fillReady
 			newCmd := setRandomWallpaper(dir)
 			if cmd != nil {
 				err := cmd.Process.Kill()