Parsing Prometheus promo format using PowerShell

Question

I've looked around a while for how to go about to parse a Prometheus promo answer using PowerShell to convert published Windows system performance metrics back to PowerShell objects.

# HELP CPU_Total Total CPU load in percent of all processors combined.
# TYPE CPU_Total gauge
CPU_Total{Instance="_total"} 1.29915
# HELP Disk_Avg_Bytes_Read Average number of bytes transfered from the disk during read operations.
# TYPE Disk_Avg_Bytes_Read gauge
Disk_Avg_Bytes_Read{Instance="harddiskvolume2"} 0
# HELP Disk_Avg_Bytes_Read Average number of bytes transfered from the disk during read operations.
# TYPE Disk_Avg_Bytes_Read gauge
Disk_Avg_Bytes_Read{Instance="c"} 0
# HELP Disk_Avg_Bytes_Read Average number of bytes transfered from the disk during read operations.
# TYPE Disk_Avg_Bytes_Read gauge
Disk_Avg_Bytes_Read{Instance="_total"} 0
# HELP Disk_Avg_Bytes_Write Average number of bytes transfered to the disk during write operations.
# TYPE Disk_Avg_Bytes_Write gauge
Disk_Avg_Bytes_Write{Instance="harddiskvolume2"} 0
# HELP Disk_Avg_Bytes_Write Average number of bytes transfered to the disk during write operations.
# TYPE Disk_Avg_Bytes_Write gauge
Disk_Avg_Bytes_Write{Instance="c"} 8192
# HELP Disk_Avg_Bytes_Write Average number of bytes transfered to the disk during write operations.
# TYPE Disk_Avg_Bytes_Write gauge
Disk_Avg_Bytes_Write{Instance="_total"} 8192
# HELP Disk_sec_per_Read Average time, in seconds, of a read of data from the disk.
# TYPE Disk_sec_per_Read gauge
Disk_sec_per_Read{Instance="harddiskvolume2"} 0

There a plenty of examples in Go (How to parse Prometheus data) and C#, etc. and they all seem to refer back to the Google ProtoBuf library

Even if PowerShell can interpret C#, I haven't a clue about how to write it :)
I assume that the download for Windows is a .Net-library, but exposing the calls is a daunting task when the foundation of knowledge is PowerShell.
And I need to use a DLL-explorer to find the names of the public calls available.

So I tried to start download the .Net version of ProtBuf, with accompanying dependencies, and then install using 'Install-Package' only to end up in the error

Install-Package: Dependency loop detected for package 'protobuf-net'

But using

choco install protoc

works like a charm.

Unfortunatley, Promethues no longer supports the JSON-format, so the proto file that can be found at
https://github.com/prometheus/client_model/blob/master/io/prometheus/client/metrics.proto
is no longer maintained (although it might be in the future again).

So,

• is there a simple way to construct a parser based on the prom file in PowerShell?

Edit: Using Chocolatey to install the library instead...
Edit II: The ProtoBuf library is actually an protoc.exe file with command switches
Edit III: Found the Prometheus ebnf specification
Edit IV: Added a promo example

Answer 1

I did find prom2json, but not as a binary for Windows or easaly transferable to PowerShell.
And that would have resulted in a cmd tool anyway.

So I resorted to plain text parsing for now...

$RestCall = Invoke-RestMethod -Uri http://localhost:9700/metrics

$RestObjects = $RestCall -split "`n# HELP "

[array]$Metrics = $null
foreach ($Object in $RestObjects) {
  $Part = $Object -split "`n"

  $Help = $Part[0]
  $Type = $Part[1] # for now we only have gauge, ignore
  [array]$ValueStruct = ($Part[2] -split '[{}]').Trim(' ')

  if ($ValueStruct.Count -ne 1) {# label
    $ValueName = $ValueStruct[0]
    $Label = $ValueStruct[1] -split "="
    $LabelName = $Label[0]
    $LabelValue = $Label[1] -replace '"',''
    $Value = $ValueStruct[2]
  } else {# no label
    $ValueStruct = $Part[2] -split ' '

    $ValueName = $ValueStruct[0]
    $LabelName = $null
    $LabelValue = $null
    $Value = $ValueStruct[1]
  }
    

  $Metric = [PSCustomObject]@{
    Name    = $ValueName
    Instance = $LabelValue
    Value   = $Value
  }

  $Metrics += $Metric

}

$Metrics