Creating and modifying a single Event Rule is very easy using the ServiceNow interface, but what if you want to see all of the Event Rule filters that you have in place? I've run across this problem enough times to realize that I needed a way to dump out all of this data is a format that I could easily read. And that's why I created a PowerShell script to perform this function. The following code does just that. It outputs an HTML document to stdout (so redirect it to a file to save it) that you can then view in a browser.
Script:
[string]$userName = 'YOUR USERNAME'
[string]$userPassword = 'YOUR PASSWORD'
[securestring]$secStringPassword = ConvertTo-SecureString $userPassword -AsPlainText -Force
[pscredential]$credObject = New-Object System.Management.Automation.PSCredential ($userName, $secStringPassword)
$allrules=Invoke-WebRequest -Uri "https://YOURINSTANCE.service-now.com/api/now/table/em_match_rule" -Credential $credObject | ConvertFrom-Json
Write-Output "<html><body>"
foreach ($rule in $allrules.result) {
Add-Member -InputObject $rule -NotePropertyName json_filter -NotePropertyvalue $($rule.simple_filter|ConvertFrom-Json);
Write-Output ("<h1>" + $rule.name + "</h1>");
Write-Output ("<code>Source = " + $rule.event_class);
for ($i = 0; $i -lt $rule.json_filter.subpredicates[0].subpredicates.Count; $i++) {
$topcombination=$rule.json_filter.subpredicates[0].compound_type.ToUpper();
if ($i -eq 0) {
$outstring = " AND</BR>(";
} else {
$outstring = "";
}
for ($j = 0; $j -lt $rule.json_filter.subpredicates[0].subpredicates[$i].subpredicates.Count; $j++) {
if ($j -eq 0) {
$outstring = $outstring + "(";
}
$outstring = ($outstring + $rule.json_filter.subpredicates[0].subpredicates[$i].subpredicates[$j].field.name + " " +
$rule.json_filter.subpredicates[0].subpredicates[$i].subpredicates[$j].operator.name + " " +
$rule.json_filter.subpredicates[0].subpredicates[$i].subpredicates[$j].field.value)
if ($j -lt ($rule.json_filter.subpredicates[0].subpredicates[$i].subpredicates.Count - 1)) {
$outstring = $outstring + " " + $rule.json_filter.subpredicates[0].subpredicates[$i].compound_type.ToUpper() + "</BR>";
}
if ($j -eq ($rule.json_filter.subpredicates[0].subpredicates[$i].subpredicates.Count - 1)) {
$outstring = ($outstring + ")");
}
}
if ($i -lt ($rule.json_filter.subpredicates[0].subpredicates.Count - 1)) {
$outstring = ($outstring + " " + $topcombination + "</BR>");
} else {
$outstring = ($outstring + ")");
}
Write-Output $outstring;
}
Write-Output "</code>";
}
Write-Output "</body></html>";
The following is a screenshot of the (somewhat ugly, but useful IMO) output produced:
Let me know if you have a usecase or suggestions for improvement!
Frank
