From 269ace1d1c80b0c26796a3af595b71af10ad1816 Mon Sep 17 00:00:00 2001
From: Bernard Xie <bernard@terrastruct.com>
Date: Thu, 17 Nov 2022 19:02:25 -0800
Subject: [PATCH] PR comments

---
 cmd/d2/main.go          |  2 +-
 cmd/d2/watch.go         |  6 +-----
 lib/png/generate_png.js |  2 +-
 lib/png/png.go          | 14 +++++++-------
 4 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/cmd/d2/main.go b/cmd/d2/main.go
index e423166bc..b21467b9e 100644
--- a/cmd/d2/main.go
+++ b/cmd/d2/main.go
@@ -122,7 +122,7 @@ func run(ctx context.Context, ms *xmain.State) (err error) {
 		defer func() {
 			cleanupErr := pw.Cleanup()
 			if cleanupErr != nil {
-				ms.Log.Error.Printf("error cleaning up png exporter: %v", cleanupErr.Error())
+				ms.Log.Error.Printf("error cleaning up playwright: %v", cleanupErr.Error())
 			}
 		}()
 	}
diff --git a/cmd/d2/watch.go b/cmd/d2/watch.go
index 89b74da27..0559ce04f 100644
--- a/cmd/d2/watch.go
+++ b/cmd/d2/watch.go
@@ -332,11 +332,7 @@ func (w *watcher) compileLoop(ctx context.Context) error {
 		if filepath.Ext(w.outputPath) == ".png" && !w.pw.Browser.IsConnected() {
 			newPW, err := w.pw.RestartBrowser()
 			if err != nil {
-				err = fmt.Errorf("png exporter has disconnected")
-				w.ms.Log.Error.Print(err)
-				w.broadcast(&compileResult{
-					Err: err.Error(),
-				})
+				return fmt.Errorf("playwright could not be restarted: %w", err)
 			}
 			w.pw = newPW
 		}
diff --git a/lib/png/generate_png.js b/lib/png/generate_png.js
index 1b9f7d703..133cadba8 100644
--- a/lib/png/generate_png.js
+++ b/lib/png/generate_png.js
@@ -15,7 +15,7 @@ async (imgString) => {
   canvas.height = img.height;
   const ctx = canvas.getContext("2d");
   if (!ctx) {
-    return "";
+    return new Error("could not get canvas context");
   }
   ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
   return canvas.toDataURL("image/png");
diff --git a/lib/png/png.go b/lib/png/png.go
index b54f197be..6c2c30632 100644
--- a/lib/png/png.go
+++ b/lib/png/png.go
@@ -27,11 +27,11 @@ func (pw *Playwright) RestartBrowser() (newPW Playwright, err error) {
 	return startPlaywright(pw.PW)
 }
 
-func (pw *Playwright) Cleanup() (err error) {
-	if err = pw.Browser.Close(); err != nil {
+func (pw *Playwright) Cleanup() error {
+	if err := pw.Browser.Close(); err != nil {
 		return err
 	}
-	if err = pw.PW.Stop(); err != nil {
+	if err := pw.PW.Stop(); err != nil {
 		return err
 	}
 	return nil
@@ -73,7 +73,7 @@ func InitPlaywright() (Playwright, error) {
 		cmd := exec.Command(driver.DriverBinaryLocation, "--version")
 		output, err := cmd.Output()
 		if err != nil {
-			return Playwright{}, fmt.Errorf("error getting png exporter version: %v\nplease report this issue here: https://github.com/terrastruct/d2/issues/new", err.Error())
+			return Playwright{}, fmt.Errorf("error getting playwright version: %w\nplease report this issue here: https://github.com/terrastruct/d2/issues/new", err)
 		}
 		if !bytes.Contains(output, []byte(driver.Version)) {
 			err = playwright.Install()
@@ -82,7 +82,7 @@ func InitPlaywright() (Playwright, error) {
 			}
 		}
 	} else {
-		return Playwright{}, fmt.Errorf("could not install png exporter: %v\nplease report this issue here: https://github.com/terrastruct/d2/issues/new", err.Error())
+		return Playwright{}, fmt.Errorf("could not access playwright binary location: %w\nplease report this issue here: https://github.com/terrastruct/d2/issues/new", err)
 	}
 
 	pw, err := playwright.Run()
@@ -97,13 +97,13 @@ var genPNGScript string
 
 func ExportPNG(ms *xmain.State, page playwright.Page, svg []byte) (outputImage []byte, err error) {
 	if page == nil {
-		return nil, fmt.Errorf("png exporter was not initialized properly\nplease report this issue here: https://github.com/terrastruct/d2/issues/new")
+		return nil, fmt.Errorf("playwright was not initialized properly\nplease report this issue here: https://github.com/terrastruct/d2/issues/new")
 	}
 
 	encodedSVG := base64.StdEncoding.EncodeToString(svg)
 	pngInterface, err := page.Evaluate(genPNGScript, "data:image/svg+xml;charset=utf-8;base64,"+encodedSVG)
 	if err != nil {
-		return nil, fmt.Errorf("failed to generate png: %v\nplease report this issue here: https://github.com/terrastruct/d2/issues/new", err.Error())
+		return nil, fmt.Errorf("failed to generate png: %w\nplease report this issue here: https://github.com/terrastruct/d2/issues/new", err)
 	}
 
 	pngString := fmt.Sprintf("%v", pngInterface)