Cloudmarque.Azure

1.0.17

Public/Deploy/Monitor/logAlerts/New-CmAzMonitorLogAlerts.ps1

function New-CmAzMonitorLogAlerts {

    <#
        .Synopsis
         Allows definiton and deployment of log alerts to set action groups.
 
        .Description
         Deploys log alert rules using custom log analytics queries to specfied action groups, this can be used in the following ways:
            * Utilising the default log alert rule definition for the deployment.
            * Overriding the default log alert rule definition with custom query, schedule, threshold and severity values, additional custom parameters can also be passed.
            * On top of the above, custom actions specifying email subjects and webhook json payloads can be specified.
            * Custom reusable log alert rule definitions can also be defined and deployed.
 
        .Parameter SettingsFile
         File path for the settings file to be converted into a settings object.
 
        .Parameter SettingsObject
         Object containing the configuration values required to run this cmdlet.
 
        .Component
         Monitor
 
        .Example
         New-CmAzMonitorLogAlerts -SettingsFile "c:\directory\settingsFile.yml" -Confirm:$false
 
        .Example
         New-CmAzMonitorLogAlerts -SettingsObject $settings
    #>

    [CmdletBinding(SupportsShouldProcess, ConfirmImpact = "Medium")]
    param(
        [parameter(Mandatory = $true, ParameterSetName = "Settings File")]
        [string]$SettingsFile,
        [parameter(Mandatory = $true, ParameterSetName = "Settings Object")]
        [object]$SettingsObject
    )

    $ErrorActionPreference = "Stop"

    try {

        Write-CommandStatus -CommandName $MyInvocation.MyCommand.Name

        $SettingsObject = Get-Settings -SettingsFile $SettingsFile -SettingsObject $SettingsObject -CmdletName (Get-CurrentCmdletName -ScriptRoot $PSCommandPath)

        if ($PSCmdlet.ShouldProcess((Get-CmAzSubscriptionName), "Deploy monitor log alerts")) {

            $standardDefinitions = Get-CmAzSettingsFile -Path "$PSScriptRoot/standardDefinitions.yml"

            $workspace = Get-CmAzService -Service $SettingsObject.service.dependencies.workspace -ThrowIfUnavailable -ThrowIfMultiple

            $resourceGroup = Check-MonitorResourceGroup -AlertType "Log"

            $alerts = @()

            foreach ($group in $SettingsObject.groups) {

                foreach ($alertSet in $SettingsObject.groups.alertSets) {

                    $query = $standardDefinitions.Queries.($alertSet.type)

                    for ($i = 0; $i -lt $alertSet.alerts.count; $i++) {

                        $alert = $alertSet.alerts[$i]

                        Set-GlobalServiceValues -GlobalServiceContainer $SettingsObject -ServiceKey "actionGroups" -ResourceServiceContainer $alert -IsDependency

                        if ($alert.definition) {

                            $definition = $query | Where-Object { $_.definition -eq $alert.definition }

                            if (!$definition) {
                                Write-Error "$($alert.definition) is not a valid definition..." -Category InvalidArgument -CategoryTargetName "definition"
                            }

                            if (!$alert.schedule) {
                                $alert.schedule = $definition.schedule
                            }

                            if (!$alert.severity) {
                                $alert.severity = $definition.severity
                            }

                            if (!$alert.suppress) {
                                $alert.suppress = $definition.suppress
                            }

                            if (!$alert.threshold) {
                                $alert.threshold = $definition.threshold
                            }

                            if (!$alert.description) {
                                $alert.description = $definition.description
                            }

                            if (!$alert.description) {
                                $alert.description = $definition.description
                            }

                            if (!$alert.query) {

                                foreach ($default in $definition.defaults?.GetEnumerator()) {

                                    $placeHolder = "@@@$($default.name)@@@"

                                    if (!$alert.parameters.$($default.name)) {
                                        $value = $default.value
                                    }
                                    else {
                                        $value = $alert.parameters.$($default.name)
                                    }

                                    $definition.query = $definition.query.replace($placeHolder, $value)
                                }

                                $alert.query = $definition.query
                            }
                        }


                        $errorMessage = "Please provide a valid {0} for alert {1}"

                        if (!$alert.schedule) {
                            Write-Error ($errorMessage -f "schedule", $alert.name) -Category InvalidArgument -CategoryTargetName "schedule"
                        }

                        if ($null -eq $alert.severity) {
                            Write-Error ($errorMessage -f "severity", $alert.name) -Category InvalidArgument -CategoryTargetName "severity"
                        }
                        elseif (!$standardDefinitions.Severity.GetEnumerator().name -contains $alert.severity) {
                            Write-Error "Please use an existing severity definition for alert $($alert.name)" -Category InvalidArgument -CategoryTargetName "severity"
                        }

                        if (!$alert.suppress) {
                            Write-Error ($errorMessage -f "suppress", $alert.name) -Category InvalidArgument -CategoryTargetName "supress"
                        }

                        if (!$alert.threshold) {
                            Write-Error ($errorMessage -f "threshold", $alert.name) -Category InvalidArgument -CategoryTargetName "threshold"
                        }

                        if (!$alert.description) {
                            Write-Error ($errorMessage -f "description", $alert.name) -Category InvalidArgument -CategoryTargetName "description"
                        }

                        if (!$alert.query) {
                            Write-Error ($errorMessage -f "query", $alert.name) -Category InvalidArgument -CategoryTargetName "query"
                        }

                        if (!$alert.suppress -or !$alert.suppress.enabled) {
                            $alert.suppress = ""
                        }

                        if (!$alert.monitorOnPrem) {
                            $alert.query += "`n| where isnotempty(_ResourceId) and isnotnull(_ResourceId)"
                        }

                        if ( $alert.exclusions -and $definition.propertiesAvailable -contains "Computer" ) {

                            Write-Verbose "Found computer exclusion..."

                            $exclusions = @()

                            foreach ($service in $alert.exclusions) {

                                $resource = Get-CmAzService -Service $service -ServiceKey "cm-monitor-exception"

                                if (!$resource) {

                                    $resource = Get-CmAzService -Service $service -ThrowIfUnavailable
                                }

                                $exclusions += $resource.resourceName
                            }

                            $alert.query += "`n| where Computer !in~ ($('"{0}"' -f ($exclusions -join '","')))"
                        }

                        $alert.enabled ??= $true
                        $alert.severity = $standardDefinitions.Severity.$($alert.severity)
                        $alert.actionGroupInfo = @{ actionGroup = @(); }

                        foreach ($actionGroup in $alert.service.dependencies.actionGroups) {
                            $alert.actionGroupInfo.actionGroup += (Get-CmAzService -Service $actionGroup -ThrowIfUnavailable -ThrowIfMultiple).resourceId
                        }

                        if ($alert.customisedActions) {

                            $alert.actionGroupInfo.emailSubject = $alert.customisedActions.emailSubject
                            $alert.actionGroupInfo.customWebhookPayload = $alert.customisedActions.webhookJsonPayload
                        }

                        $name = $group.name

                        if ($alertSet.name) {
                            $name += "-$($alertSet.name)"
                        }

                        if ($alert.name) {
                            $name += "-$($alert.name)"
                        }

                        $alertName = Get-CmAzResourceName -Resource "Alert" -Architecture "Monitor" -Location $workspace.location -Name "log-$name-$i"

                        Set-GlobalServiceValues -GlobalServiceContainer $SettingsObject -ServiceKey "logAlert" -ResourceServiceContainer $alert

                        $alerts += @{
                            name        = $alertName;
                            enabled     = $alert.enabled;
                            query       = $alert.query;
                            suppress    = $alert.suppress;
                            schedule    = $alert.schedule;
                            aznsAction  = $alert.actionGroupInfo;
                            threshold   = $alert.threshold;
                            description = $alert.description;
                            severity    = $alert.severity;
                            service     = $alert.service;
                        }
                    }
                }
            }

            $deploymentName = Get-CmAzResourceName -Resource "Deployment" -Architecture "Monitor" -Location $workspace.location -Name $MyInvocation.MyCommand.Name

            New-AzResourceGroupDeployment `
                -Name $deploymentName `
                -TemplateFile "$PSScriptRoot\New-CmAzMonitorLogAlerts.json" `
                -ResourceGroupName $resourceGroup.resourceGroupName `
                -TemplateParameterObject @{
                    Alerts    = $alerts
                    Workspace = $workspace
                }`
                -Mode "Complete"

            Set-DeployedResourceTags -TagSettingsFile $TagSettingsFile -ResourceGroupIds $resourceGroup.resourceGroupName

            Write-CommandStatus -CommandName $MyInvocation.MyCommand.Name -Start $false
        }
    }
    catch {
        $PSCmdlet.ThrowTerminatingError($PSItem);
    }
}