Parsing Rest query output

Question

I am trying to parse the output of a rest api query of the form

$response = Invoke-RestMethod -Uri $uri -Headers $headers
$response.name | Select-String -Pattern ^role

returns an output similar to this below (elements separated by ::)

role::servicing2
role::collaboration::lei
role::commercial_lines::npds
role::nvp::windows::ucce_gold
role::oracle::linux::oracle_oid
role::splunk::splunk_enterprise::add_on

I need to read this output line by line and parse.

If there are just 2 elements eg. role::servicing2 ignore the line
If there are 3 elements, ignore the first element "role", prepend puppet_ to the second element and it becomes the project, the third element is the role (OS is unknown)
If there are 4 or more elements, ignore the first element "role", prepend puppet_ to the second element and it becomes the project, if the third element is "windows" or "linux" that is the OS, else OS is "unknown", and the last element \:\:'(\w+)'$ is the role.

Need an output in the form of an array or table or list in this format (Don't necessarily need header)

Project         OS      Role

puppet_collaboration    unknown     lei
puppet_commercial_lines unknown     npds
puppet_nvp      windows     ucce_gold
puppet_oracle       linux       oracle_oid
puppet_splunk       unknown     add_on

I have tried various regex expressions. Couldn't figure out the logic of walking this line by line and parsing appropriately into a list or array.

"I have tried various regex expressions. Couldn't figure out the logic of walking this line by line and parsing appropriately into a list or array." - can you share what you tried so far, and how it failed? :) — Mathias R. Jessen
– Mathias R. Jessen, Commented Sep 27, 2019 at 13:11
I was trying to parse along the lines of $response.name | Select-String -Pattern ^role\:\:'(\w+)'\:\:'(\w+)'$ | foreach {$_.Matches.Groups[2].Value}. Not sure how to add all the logic above. — abrahavt
– abrahavt, Commented Sep 27, 2019 at 13:58

Theo · Accepted Answer · 2019-09-27 14:09:47Z

2

I think below code should do what you want:

$roles = @'
role::servicing2
role::collaboration::lei
role::commercial_lines::npds
role::nvp::windows::ucce_gold
role::oracle::linux::oracle_oid
role::splunk::splunk_enterprise::add_on
'@ -split '\r?\n'

$result = $roles | ForEach-Object {
    $parts = $_ -split '::'
    switch ($parts.Count) {
        2 { continue }  # ignore this line
        3 { 
            [PsCustomObject]@{
                'Project' = 'puppet_{0}' -f $parts[1]
                'OS'      = 'unknown'
                'Role'    = $parts[2]
            }
        }
        default {
            [PsCustomObject]@{
                'Project' = 'puppet_{0}' -f $parts[1]
                'OS'      = if ('windows', 'linux' -contains $parts[2]) {$parts[2]} else {'unknown'}
                'Role'    = $parts[-1]
            }        
        }
    }
}

# output on screen
$result

# output to CSV file
$result | Export-Csv -Path 'D:\roles.csv' -NoTypeInformation

For testing I have put the result of your $response.name | Select-String -Pattern ^role in a here-string.

Output:

Project                 OS      Role      
-------                 --      ----      
puppet_collaboration    unknown lei       
puppet_commercial_lines unknown npds      
puppet_nvp              windows ucce_gold 
puppet_oracle           linux   oracle_oid
puppet_splunk           unknown add_on

answered Sep 27, 2019 at 14:09

Theo

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1 Comment

abrahavt Over a year ago

This worked great. Thank you very much. I learned a lot from it.

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