Add a silent try catch while printing previous log tail (Azure-App-Se…

…rvice#87)
Hazhzeng · Aug 19, 2019 · 1412828 · 1412828
1 parent ee1015b
commit 1412828
Showing 1 changed file with 26 additions and 16 deletions.
diff --git a/Kudu.Services/Diagnostics/LogStreamManager.cs b/Kudu.Services/Diagnostics/LogStreamManager.cs
@@ -103,7 +103,7 @@ public async Task ProcessRequest(HttpContext context)
 
             FileSystemHelpers.EnsureDirectory(mountedLogFilesDir);
 
-            if (shouldMonitiorMountedLogsPath(mountedLogFilesDir))
+            if (ShouldMonitiorMountedLogsPath(mountedLogFilesDir))
             {
                 path = mountedLogFilesDir;
             }
@@ -127,33 +127,43 @@ public async Task ProcessRequest(HttpContext context)
             {
                 NotifyClientWithLineBreak("Starting Log Tail -n 10 of existing logs ----", context);
 
-                foreach (string log in _logFiles.Keys)
+                try
                 {
-                    var reader = new StreamReader(log, Encoding.ASCII);
 
-                    var vfsPath = GetFileVfsPath(log);
 
-                    var printLine = log + " " + (!string.IsNullOrEmpty(vfsPath) ? " (" + vfsPath + ")" : "");
+                    foreach (string log in _logFiles.Keys)
+                    {
+
+                        var reader = new StreamReader(log, Encoding.ASCII);
 
-                    NotifyClientWithLineBreak(String.Format(
-                                CultureInfo.CurrentCulture,
-                                printLine,
-                                DateTime.UtcNow.ToString("s"),
-                                System.Environment.NewLine),context);
+                        var vfsPath = GetFileVfsPath(log);
 
-                    foreach (string logLine in Tail(reader, 10))
-                    {
-                        await context.Response.WriteAsync(logLine);
+                        var printLine = log + " " + (!string.IsNullOrEmpty(vfsPath) ? " (" + vfsPath + ")" : "");
+
+                        NotifyClientWithLineBreak(String.Format(
+                                    CultureInfo.CurrentCulture,
+                                    printLine,
+                                    DateTime.UtcNow.ToString("s"),
+                                    System.Environment.NewLine), context);
+
+                        foreach (string logLine in Tail(reader, 10))
+                        {
+                            await context.Response.WriteAsync(logLine);
+                            await context.Response.WriteAsync(System.Environment.NewLine);
+                        }
                         await context.Response.WriteAsync(System.Environment.NewLine);
                     }
-                    await context.Response.WriteAsync(System.Environment.NewLine);
                 }
+                catch (Exception)
+                {
+                    // best effort to get tail logs
+                }
+
                 NotifyClientWithLineBreak("Ending Log Tail of existing logs ---", context);
             }
             else
             {
                 _tracer.TraceError("LogStream: No pervious logfiles");
-                Console.WriteLine("LogStream: No pervious logfiles");
             }
 
             NotifyClientWithLineBreak("Starting Live Log Stream ---", context);
@@ -239,7 +249,7 @@ private static Task WriteInitialMessage(HttpContext context)
         /// or the mounted fs logs dir, if kudu
         /// </summary>
         /// <returns></returns>
-        private static bool shouldMonitiorMountedLogsPath(string mountedDirPath)
+        private static bool ShouldMonitiorMountedLogsPath(string mountedDirPath)
         {
             int count = 0;
             string dateToday = DateTime.Now.ToString("yyyy_MM_dd");