Commandline/object-model to inspect a binlog for errors/warnings

A typical way in with file logs are used esp. in local/dev-builds goes like this:

$warn = Get-Content msbuild.wrn
$err = Get-Content msbuild.err 

if (warn.length -gt 0) {
    Write-Error "Warnings Found"
}

if (err.length -gt 0) {
    Write-Error "Errors Found"
}

I’m wondering if there is a simple way to replace file-logs with binary-logs for this type of scenario. Specifically, if there is a simple approach (for e.g., using powershell) to inspect a binary log for these (without replaying the log using msbuild - that would defeat the purpose of replacing file-logs with binary-logs):

• Number of errors (or whether errors exist)
  • The error text
• Number of warnings (or whether warnings exist)
  • The warning text

[KirillOsenkov]

Hey @stephentoub @danmosemsft Vatsan has found an interesting scenario where reading a binlog takes 4 seconds on .NET Desktop, but 40 seconds on Core 3.1.

Repro:

1. git clone https://github.com/vatsan-madhavan/MSBuildStructuredLogSummary
2. msbuild /r
3. Download the binlog from https://1drv.ms/u/s!Ah63gfGkKca4lsl2sy71gpkpM9TCog?e=ifgsMj and save it anywhere, e.g. C:\temp\vatsan\vatsan.binlog
4. MSBuildBinLogSummary\bin\Debug\net472\MSBuildBinLogSummary.exe --log-file C:\temp\Vatsan\vatsan.binlog - takes 4 seconds
5. MSBuildBinLogSummary\bin\Debug\netcoreapp3.1\MSBuildBinLogSummary.exe --log-file C:\temp\Vatsan\vatsan.binlog - takes 40 seconds

The stack that I saw was taking all the time is ReadByte from a GzipStream, it’s called millions of times (to read the binlog):

  | ZLibNative.ZLibStreamHandle.Inflate Line 300
-- | --
  | Inflater.Inflate Line 281
  | Inflater.ReadInflateOutput Line 266
  | Inflater.ReadOutput Line 122
  | Inflater.InflateVerified Line 92
  | Inflater.Inflate Line 55
  | DeflateStream.ReadByte Line 229
  | GZipStream.ReadByte Line 72
  | BinaryReader.ReadBoolean Line 236
  | BuildEventArgsReader.ReadTargetFinishedEventArgs Line 359
  | BuildEventArgsReader.Read Line 71
  | BinLogReader.Replay Line 78
  | BinLogReader.Replay Line 37
  | StructuredLoggerUtil..ctor Line 30
  | Program.ProcessBinaryLog Line 29
  | Program.Main Line 24

Is this something known? On Desktop Framework I see a similar native inflate stack, but it doesn’t cost nearly as much. Would someone be able to take a look? Thanks!

[KirillOsenkov]

Yes, try build.FindChildrenRecursive<Error> and build.FindChildrenRecursive<Warning>