问题
I'm using a PowerShell script to control different compilation steps of an compiler (ghdl.exe).
The compiler has 3 different output formats:
- No output and no error => $LastExitCode = 0
- outputs on stderr (warnings), but no errors => $LastExitCode = 0
- outputs on stderr (errors), and maybe warnings => $LastExitCode != 0
Because handling of stderr and stdout seams to be very buggy, I used the method presented in this StackOverflow post: PowerShell: Manage errors with Invoke-Expression
Here is my implementation with addition message coloring:
function Format-NativeCommandStreams
{ param([Parameter(ValueFromPipeline=$true)]$InputObject)
begin
{ $ErrorRecordFound = $false }
process
{ if (-not $InputObject)
{ Write-Host "Empty" }
elseif ($InputObject -is [System.Management.Automation.ErrorRecord])
{ $ErrorRecordFound = $true
$text = $InputObject.ToString()
Write-Host $text -ForegroundColor Gray
$stdErr = $InputObject.TargetObject
if ($stdErr)
{ #Write-Host ("err: type=" + $stdErr.GetType() + " " + $stdErr)
if ($stdErr.Contains("warning"))
{ Write-Host "WARNING: " -NoNewline -ForegroundColor Yellow }
else
{ Write-Host "ERROR: " -NoNewline -ForegroundColor Red }
Write-Host $stdErr
}
}
else
{ $stdOut = $InputObject
if ($stdOut.Contains("warning"))
{ Write-Host "WARNING: " -NoNewline -ForegroundColor Yellow }
else
{ Write-Host "ERROR: " -NoNewline -ForegroundColor Red }
Write-Host $stdOut
}
}
end
{ $ErrorRecordFound }
}
Usage:
$Options = @(.....)
$Expr = "ghdl.exe -a " + ($Options -join " ") + " " + $File + " 2>&1"
$ret = Invoke-Expression $Expr | Format-NativeCommandStreams
Normally, the compiler emits one message (error or warning) per line. As shown in the screenshot below, some messages got chopped in up to 8 lines. That's the reason why my output coloring does not work as expected. More over some lines are detected as errors (false positives), so I can't find the real error in the logs.
(clickable)
Example:
C:\Altera\15.0\quartus\eda\sim_lib\altera_mf.vhd:
39963:
53
:
warning:
universal integer bound must be numeric literal or attribute
C:\Altera\15.0\quartus\eda\sim_lib\altera_mf.vhd
:41794:36:warning: universal integer bound must be numeric literal or attribute
Expected Result:
C:\Altera\15.0\quartus\eda\sim_lib\altera_mf.vhd:39963:53:warning: universal integer bound must be numeric literal or attribute
C:\Altera\15.0\quartus\eda\sim_lib\altera_mf.vhd:41794:36:warning: universal integer bound must be numeric literal or attribute
As far as I can see, the compiler (ghdl.exe) does emit the messages as full lines.
Questions:
- Why does this happen?
- Who can I solve this?
回答1:
Solution
The complete output on stderr of the executable is simply split across several objects of type System.Management.Automation.ErrorRecord. The actual splitting seems to be non deterministic (*). Moreover, the partial strings are stored inside the property Exception instead of TargetObject. Only the first ErrorRecord has a non-null TargetObject. That is, why subsequent lines of your output containing the string "warning" are not formatted in yellow and white, like this one:
:41794:36:warning: universal integer bound must be numeric literal or attribute
Your grey output comes from the toString() method of each ErrorRecord which returns the value of the property Exception.Message of this record.
So one must concatenate all messages together to get the whole output before formatting it. Newlines are preserved in these messages.
EDIT: (*) It depends on the order of write/flush calls of the program in relation to the read calls of the Powershell. If one adds a fflush(stderr) after each fprintf() in my test program below, there will be much more ErrorRecord objects. Except the first one, which seems deterministic, some of them include 2 output lines and some of them 3.
My testbench
Instead of using GHDL I started with a new Visual Studio project and created a console application (HelloWorldEx) with the following code. It simply prints out a lot of numbered lines on stderr
#include "stdafx.h"
#include <stdio.h>
int _tmain(int argc, _TCHAR* argv[])
{
// Print some warning messages on stderr
for(int i=0; i<70; i++) {
fprintf(stderr, "warning:%070d\n", i); // 80 bytes per line including CR+LF
}
return 0; // exit code is not relevant
}
Then I compiled the program and executed it inside the Powershell with: (EDIT: removed debug code from my own script)
.\HelloWorldEx.exe 2>&1 | set-variable Output
$i = 0
$Output | % {
Write-Host ("--- " + $i + ": " + $_.GetType() + " ------------------------")
Write-Host ($_ | Format-List -Force | Out-String)
$i++
}
This was the output of the script. As you can see, the output of my program is split accross 3 ErrorRecords (the actual might differ):
--- 0: System.Management.Automation.ErrorRecord ------------------------
writeErrorStream : True
Exception : System.Management.Automation.RemoteException: warning:00000000000000000000000000000000000000000
00000000000000000000000000000
TargetObject : warning:0000000000000000000000000000000000000000000000000000000000000000000000
CategoryInfo : NotSpecified: (warning:0000000...000000000000000:String) [], RemoteException
FullyQualifiedErrorId : NativeCommandError
ErrorDetails :
InvocationInfo : System.Management.Automation.InvocationInfo
PipelineIterationInfo : {0, 0, 0}
PSMessageDetails :
--- 1: System.Management.Automation.ErrorRecord ------------------------
writeErrorStream : True
Exception : System.Management.Automation.RemoteException: warning:00000000000000000000000000000000000000000
00000000000000000000000000001
warning:0000000000000000000000000000000000000000000000000000000000000000000002
warning:0000000000000000000000000000000000000000000000000000000000000000000003
warning:0000000000000000000000000000000000000000000000000000000000000000000004
warning:0000000000000000000000000000000000000000000000000000000000000000000005
warning:0000000000000000000000000000000000000000000000000000000000000000000006
warning:0000000000000000000000000000000000000000000000000000000000000000000007
warning:0000000000000000000000000000000000000000000000000000000000000000000008
warning:0000000000000000000000000000000000000000000000000000000000000000000009
warning:0000000000000000000000000000000000000000000000000000000000000000000010
warning:0000000000000000000000000000000000000000000000000000000000000000000011
warning:0000000000000000000000000000000000000000000000000000000000000000000012
warning:0000000000000000000000000000000000000000000000000000000000000000000013
warning:0000000000000000000000000000000000000000000000000000000000000000000014
warning:0000000000000000000000000000000000000000000000000000000000000000000015
warning:0000000000000000000000000000000000000000000000000000000000000000000016
warning:0000000000000000000000000000000000000000000000000000000000000000000017
warning:0000000000000000000000000000000000000000000000000000000000000000000018
warning:0000000000000000000000000000000000000000000000000000000000000000000019
warning:0000000000000000000000000000000000000000000000000000000000000000000020
warning:0000000000000000000000000000000000000000000000000000000000000000000021
warning:0000000000000000000000000000000000000000000000000000000000000000000022
warning:0000000000000000000000000000000000000000000000000000000000000000000023
warning:0000000000000000000000000000000000000000000000000000000000000000000024
warning:0000000000000000000000000000000000000000000000000000000000000000000025
warning:0000000000000000000000000000000000000000000000000000000000000000000026
warning:0000000000000000000000000000000000000000000000000000000000000000000027
warning:0000000000000000000000000000000000000000000000000000000000000000000028
warning:0000000000000000000000000000000000000000000000000000000000000000000029
warning:0000000000000000000000000000000000000000000000000000000000000000000030
warning:0000000000000000000000000000000000000000000000000000000000000000000031
warning:0000000000000000000000000000000000000000000000000000000000000000000032
warning:0000000000000000000000000000000000000000000000000000000000000000000033
warning:0000000000000000000000000000000000000000000000000000000000000000000034
warning:0000000000000000000000000000000000000000000000000000000000000000000035
warning:0000000000000000000000000000000000000000000000000000000000000000000036
warning:0000000000000000000000000000000000000000000000000000000000000000000037
warning:0000000000000000000000000000000000000000000000000000000000000000000038
warning:0000000000000000000000000000000000000000000000000000000000000000000039
warning:0000000000000000000000000000000000000000000000000000000000000000000040
warning:0000000000000000000000000000000000000000000000000000000000000000000041
warning:0000000000000000000000000000000000000000000000000000000000000000000042
warning:0000000000000000000000000000000000000000000000000000000000000000000043
warning:0000000000000000000000000000000000000000000000000000000000000000000044
warning:0000000000000000000000000000000000000000000000000000000000000000000045
warning:0000000000000000000000000000000000000000000000000000000000000000000046
warning:0000000000000000000000000000000000000000000000000000000000000000000047
warning:0000000000000000000000000000000000000000000000000000000000000000000048
warning:0000000000000000000000000000000000000000000000000000000000000000000049
warning:0000000000000000000000000000000000000000000000000000000000000000000050
warning:00000000000000000000000000000000000000000000000000000000000
TargetObject :
CategoryInfo : NotSpecified: (:) [], RemoteException
FullyQualifiedErrorId : NativeCommandErrorMessage
ErrorDetails :
InvocationInfo : System.Management.Automation.InvocationInfo
PipelineIterationInfo : {0, 0, 1}
PSMessageDetails :
--- 2: System.Management.Automation.ErrorRecord ------------------------
writeErrorStream : True
Exception : System.Management.Automation.RemoteException: 00000000051
warning:0000000000000000000000000000000000000000000000000000000000000000000052
warning:0000000000000000000000000000000000000000000000000000000000000000000053
warning:0000000000000000000000000000000000000000000000000000000000000000000054
warning:0000000000000000000000000000000000000000000000000000000000000000000055
warning:0000000000000000000000000000000000000000000000000000000000000000000056
warning:0000000000000000000000000000000000000000000000000000000000000000000057
warning:0000000000000000000000000000000000000000000000000000000000000000000058
warning:0000000000000000000000000000000000000000000000000000000000000000000059
warning:0000000000000000000000000000000000000000000000000000000000000000000060
warning:0000000000000000000000000000000000000000000000000000000000000000000061
warning:0000000000000000000000000000000000000000000000000000000000000000000062
warning:0000000000000000000000000000000000000000000000000000000000000000000063
warning:0000000000000000000000000000000000000000000000000000000000000000000064
warning:0000000000000000000000000000000000000000000000000000000000000000000065
warning:0000000000000000000000000000000000000000000000000000000000000000000066
warning:0000000000000000000000000000000000000000000000000000000000000000000067
warning:0000000000000000000000000000000000000000000000000000000000000000000068
warning:0000000000000000000000000000000000000000000000000000000000000000000069
TargetObject :
CategoryInfo : NotSpecified: (:) [], RemoteException
FullyQualifiedErrorId : NativeCommandErrorMessage
ErrorDetails :
InvocationInfo : System.Management.Automation.InvocationInfo
PipelineIterationInfo : {0, 0, 2}
PSMessageDetails :
回答2:
You can a bit of debugging to sort this out. I suggest starting with something like this:
ghdl.exe <whatever args you supply> 2>&1 | set-variable ghdlOutput
$i = 0
$ghdlOutput | % {write-host "$i `t: " $_.gettype() "`t" $_ ; $i++}
This will list the line number, type of the output line, and each live of the output. You may have to tweak the code some to get the output to look OK.
From there you can see if the compiler is really splitting up errors into multiple lines. If it is you can try devise a strategy for determining which lines are stdout and which are stderr. If not, then you'll have some clues to debugging your script above.
Or can bag this whole approach and use the .NET system.diagnostics.process class and redirect stdout and stderr as separate streams. Use the Start method that takes a ProcessStartInfo. You should be able to google examples of doing this if you need to.
回答3:
Just for completeness, here are my current CommandLets, which restore the error messages as a single line and color them as wanted:
Usage:
$InvokeExpr = "ghdl.exe " + ($Options -join " ") + " --work=unisim " + $File.FullName + " 2>&1"
$ErrorRecordFound = Invoke-Expression $InvokeExpr | Collect-NativeCommandStream | Write-ColoredGHDLLine
CommandLet to restore the error messages:
function Collect-NativeCommandStream
{ [CmdletBinding()]
param([Parameter(ValueFromPipeline=$true)]$InputObject)
begin
{ $LineRemainer = "" }
process
{ if (-not $InputObject)
{ Write-Host "Empty pipeline!" }
elseif ($InputObject -is [System.Management.Automation.ErrorRecord])
{ if ($InputObject.FullyQualifiedErrorId -eq "NativeCommandError")
{ Write-Output $InputObject.ToString() }
elseif ($InputObject.FullyQualifiedErrorId -eq "NativeCommandErrorMessage")
{ $NewLine = $LineRemainer + $InputObject.ToString()
while (($NewLinePos = $NewLine.IndexOf("`n")) -ne -1)
{ Write-Output $NewLine.Substring(0, $NewLinePos)
$NewLine = $NewLine.Substring($NewLinePos + 1)
}
$LineRemainer = $NewLine
}
}
elseif ($InputObject -is [String])
{ Write-Output $InputObject }
else
{ Write-Host "Unsupported object in pipeline stream" }
}
end
{ }
}
CommandLet to color warnings and errors:
function Write-ColoredGHDLLine
{ [CmdletBinding()]
param([Parameter(ValueFromPipeline=$true)]$InputObject)
begin
{ $ErrorRecordFound = $false }
process
{ if (-not $InputObject)
{ Write-Host "Empty pipeline!" }
elseif ($InputObject -is [String])
{ if ($InputObject.Contains("warning"))
{ Write-Host "WARNING: " -NoNewline -ForegroundColor Yellow }
else
{ $ErrorRecordFound = $true
Write-Host "ERROR: " -NoNewline -ForegroundColor Red
}
Write-Host $InputObject
}
else
{ Write-Host "Unsupported object in pipeline stream" }
}
end
{ $ErrorRecordFound }
}
来源：https://stackoverflow.com/questions/33838633/why-does-powershell-chops-message-on-stderr