[wasm][debugger] Clean up startup and improve comments

Properly await more of the async logic and add retries when we get
an empty response from the "json/list" endpoint.

1 files changed, 38 insertions, 27 deletions

diff --git a/sdks/wasm/ProxyDriver/TestHarnessStartup.cs b/sdks/wasm/ProxyDriver/TestHarnessStartup.cs
index 19a3bb9e95b..325781d9cb3 100644
--- a/sdks/wasm/ProxyDriver/TestHarnessStartup.cs
+++ b/sdks/wasm/ProxyDriver/TestHarnessStartup.cs
@@ -64,8 +64,9 @@ namespace WsProxy {
 			} catch (Exception e) { Console.WriteLine (e); }
 		}
 
-		public async Task LaunchAndServe (ProcessStartInfo psi, HttpContext context, Func<string, string> extract_conn_url)
+		public async Task LaunchAndServe (ProcessStartInfo psi, HttpContext context, Func<string, Task<string>> extract_conn_url)
 		{
+
 			if (!context.WebSockets.IsWebSocketRequest) {
 				context.Response.StatusCode = 400;
 				return;
@@ -76,14 +77,20 @@ namespace WsProxy {
 			var proc = Process.Start (psi);
 			try {
 				proc.ErrorDataReceived += (sender, e) => {
-					Console.WriteLine ($"stderr: {e.Data}");
-					var res = extract_conn_url (e.Data);
-					if (res != null)
-						tcs.TrySetResult (res);
+					var str = e.Data;
+					Console.WriteLine ($"stderr: {str}");
+
+					if (str.Contains ("listening on", StringComparison.Ordinal)) {
+						var res = str.Substring (str.IndexOf ("ws://", StringComparison.Ordinal));
+						if (res != null)
+							tcs.TrySetResult (res);
+					}
 				};
+
 				proc.OutputDataReceived += (sender, e) => {
 					Console.WriteLine ($"stdout: {e.Data}");
 				};
+
 				proc.BeginErrorReadLine ();
 				proc.BeginOutputReadLine ();
 
@@ -91,7 +98,9 @@ namespace WsProxy {
 					Console.WriteLine ("Didnt get the con string after 2s.");
 					throw new Exception ("node.js timedout");
 				}
-				var con_str = await tcs.Task;
+				var line = await tcs.Task;
+				var con_str = extract_conn_url != null ? await extract_conn_url (line) : line;
+
 				Console.WriteLine ($"lauching proxy for {con_str}");
 
 				var proxy = new MonoProxy ();
@@ -101,7 +110,7 @@ namespace WsProxy {
 				await proxy.Run (browserUri, ideSocket);
 				Console.WriteLine("Proxy done");
 			} catch (Exception e) {
-				Console.WriteLine ("got exception {0}", e.GetType ().FullName);
+				Console.WriteLine ("got exception {0}", e);
 			} finally {
 				proc.CancelErrorRead ();
 				proc.CancelOutputRead ();
@@ -142,21 +151,27 @@ namespace WsProxy {
 			app.UseRouter (router => {
 				router.MapGet ("launch-chrome-and-connect", async context => {
 					Console.WriteLine ("New test request");
-					await LaunchAndServe (psi, context, str => {
-						//We wait for it as a signal that chrome finished launching
-						if (!str.StartsWith ("DevTools listening on ", StringComparison.Ordinal))
-							return null;
-
-						// Unfortunately it does look like we have to wait
-						// for a bit after getting the response but before
-						// making the list request
-						Thread.Sleep (500);
-
-						var client = new HttpClient ();
-						var res = client.GetStringAsync (new Uri (devToolsUrl, "/json/list")).Result;
-						Console.WriteLine ("res is {0}", res);
-						if (res == null)
-							return null;
+					var client = new HttpClient ();
+					await LaunchAndServe (psi, context, async (str) => {
+						string res = null;
+						var start = DateTime.Now;
+
+						while (res == null) {
+							// Unfortunately it does look like we have to wait
+							// for a bit after getting the response but before
+							// making the list request.  We get an empty result
+							// if we make the request too soon.
+							await Task.Delay (100);
+
+							res = await client.GetStringAsync (new Uri (new Uri (str), "/json/list"));
+							Console.WriteLine ("res is {0}", res);
+
+							var elapsed = DateTime.Now - start;
+							if (res == null && elapsed.Milliseconds > 2000) {
+								Console.WriteLine ($"Unable to get DevTools /json/list response in {elapsed.Seconds} seconds, stopping");
+								return null;
+							}
+						}
 
 						var obj = JArray.Parse (res);
 						if (obj == null || obj.Count < 1)
@@ -184,11 +199,7 @@ namespace WsProxy {
 					router.MapGet ("json/list", SendNodeList);
 					router.MapGet ("json/version", SendNodeVersion);
 					router.MapGet ("launch-done-and-connect", async context => {
-						await LaunchAndServe (psi, context, str => {
-							if (str.StartsWith ("Debugger listening on", StringComparison.Ordinal))
-								return str.Substring (str.IndexOf ("ws://", StringComparison.Ordinal));
-							return null;
-						});
+						await LaunchAndServe (psi, context, null);
 					});
 				});
 			}