Powershell Compare for matches - powershell

Question

I have two files, one with the servers listed in file A and I need to use that list to search file B for matches.
File A = Server Names (2 columns, Hostname/ServiceName)
File B = Server Metrics (3 columns, Hostname/ServiceName/ServiceOutput)
I need to use the two columns from "File A" to parse "File B" and when it finds a match it needs to write that row in "File B" to an output file. Each server should have three rows in the output file however, nothing is being written.
File A
host_display_name,service_display_name
US_Server1,Disk /
US_Server1,Disk /logs
US_Server1,mem
File B
Host_Name , ServiceName , Server_Ouput
US_Server1,Disk/,Disk Metrics
US_Server1,CPU/,CPU Metrics
US_Server1,Disk/logs,Disk Logs Metrics
US_Server1,APT,APT Metrics
US_Server1,User Count,User Count Metric
US_Server1,Java,Java Metrics
US_Server1,mem,Memory Metric
NONUS_Server2,Disk/,Disk Metrics
NONUS__Server2,Disk/logs,Disk Logs Metrics
NONUS_Server2,CPU/,CPU Metrics
NONUS_Server2,APT,APT Metrics
NONUS_Server2,User Count,User Count Metric
NONUS_Server2,Java,Java Metrics
NONUS_Server2,mem,Memory Metric
US_Server2,Disk/ ,Disk Metrics
US_Server2,Disk/logs,Disk Logs Metrics
US_Server2,CPU/,CPU Metrics
US_Server2,APT,APT Metrics
US_Server2,User Count,User Count Metric
US_Server2,Java,Java Metrics
US_Server2,mem,Memory Metric
Desired Output
Host_Name,ServiceName,Server_Ouput
US_Server1,Disk/,DiskMetrics
US_Server1,Disk/logs,DiskLogsMetrics
US_Server1,mem,MemoryMetric
US_Server2,Disk/,DiskMetrics
US_Server2,Disk/logs,DiskLogsMetrics
US_Server2,mem,MemoryMetric
CODE:
$Path = "C:\Projects\Excel_Data_Powershell"
$UserList = Import-Csv -Path "$($path)\Servers.csv"
$UserData = Import-Csv -Path "$($path)\services.csv"
$UserOutput = #()
ForEach ($name in $UserList)
{
$userMatch = $UserData | where {$_.host_name -eq $name.service_name}
If($userMatch)
{
# Process the data
$UserOutput += New-Object PsObject -Property #{HostName =$name.host_name;column1 =$userMatch.service_name;column2 =$userMatch.service_output}
}
else
{
$UserOutput += New-Object PsObject -Property #{UserName =$name.hostnames;servicename ="NA";serviceoutput ="NA"}
}
}
$UserOutput | ft

Answer 1

This is how you could filter fileB based on fileA, using Group-Object -AsHashtable for reference filtering:
$fileA = Import-Csv -Path path\to\fileA.csv | Group-Object HostName -AsHashTable -AsString
$fileB = Import-Csv -Path path\to\fileB.csv
$desiredOutput = $fileB.Where({
$_.ServiceName -in $fileA[$_.'Host_Name'].ServiceName
})
$desiredOutput | Export-Csv ..... -NoTypeInformation
Above should give you the following result:
Host_Name ServiceName Server_Ouput
--------- ----------- ------------
Server1 Disk / Disk Metrics
Server1 Disk /logs Disk Logs Metrics
Server1 mem Memory Metric
Server2 Disk / Disk Metrics
Server2 Disk /logs Disk Logs Metrics
Server2 mem Memory Metric
Server3 Disk / Disk Metrics
Server3 Disk /logs Disk Logs Metrics
Server3 mem Memory Metric

Answer 2

You're referencing host_name vs service_name in your where-object clause.
$UserData | where {$_.Host_Name -eq $name.HostName}
generates good results.