Logging Strategies¶

Logging is one of the defining characteristics of a professional PowerShell script. A script that performs important administrative tasks must not only do the work—it must also record what it did, when it did it, and whether it succeeded. Logging provides traceability, supports troubleshooting, enables auditing, and allows administrators to understand the script’s behavior long after it has run.

This section explains why logging matters, how to design a logging strategy, and how to implement structured, reliable logs in your PowerShell scripts.

1. The Purpose of Logging¶

A professional script logs information for several reasons:

Traceability — understanding what actions were taken
Troubleshooting — diagnosing failures or unexpected behavior
Auditing — proving that required tasks were completed
Monitoring — integrating with external systems or dashboards
Accountability — showing who ran the script and when

Without logging, a script becomes a black box. With logging, it becomes a transparent, predictable tool.

2. What to Log¶

A good logging strategy captures information that is meaningful without overwhelming the reader. Typical log entries include:

Start and end of the script
Parameter values (excluding sensitive data)
Major actions (e.g., “Creating user account: jdoe”)
Success messages
Warnings
Errors and exceptions
Summary information

The goal is to record enough detail to reconstruct what happened, but not so much that the log becomes unreadable.

3. Logging Destinations¶

PowerShell scripts commonly log to one or more of the following:

Console output¶

Useful for interactive scripts but not persistent.

Text files¶

The most common and portable option.

CSV or JSON files¶

Useful for structured data or integration with other tools.

Event logs¶

Appropriate for enterprise‑level auditing.

Centralized logging systems¶

Such as Splunk, Elastic, or SIEM platforms.

For most administrative scripts, a text log file is the simplest and most effective approach.

4. Designing a Logging Function¶

A professional script should not scatter Write-Output or Add-Content calls throughout the code. Instead, it should define a dedicated logging function that centralizes all logging behavior.

Example: a simple logging function¶

function Write-Log {
    param(
        [string]$Message,
        [string]$Level = "INFO",
        [string]$Path
    )

    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
    $entry = "$timestamp [$Level] $Message"
    Add-Content -Path $Path -Value $entry
}

This function:

Adds timestamps
Supports log levels
Writes to a consistent format
Centralizes all logging logic

Using a function ensures that logs remain uniform and easy to parse.

5. Using Log Levels¶

Log levels categorize the importance of each message. Common levels include:

INFO — normal operational messages
WARNING — something unexpected but not fatal
ERROR — a failure that prevented an action
DEBUG — detailed information for troubleshooting

Example usage¶

Write-Log -Message "Starting user creation process" -Level "INFO" -Path $LogPath
Write-Log -Message "User jdoe already exists" -Level "WARNING" -Path $LogPath
Write-Log -Message "Failed to create user jdoe" -Level "ERROR" -Path $LogPath

Log levels make it easier to filter and analyze logs.

6. Logging Script Start and End¶

A professional script always logs when it begins and when it finishes.

Example¶

Write-Log -Message "Script started." -Level "INFO" -Path $LogPath
# ... script logic ...
Write-Log -Message "Script completed successfully." -Level "INFO" -Path $LogPath

This provides a clear boundary for each execution.

7. Logging Errors and Exceptions¶

Errors should be logged with as much detail as possible. A try/catch block allows you to capture exceptions and write them to the log.

Example¶

try {
    New-ADUser -Name $Name -SamAccountName $Sam -ErrorAction Stop
    Write-Log -Message "Created user $Sam" -Level "INFO" -Path $LogPath
}
catch {
    Write-Log -Message "Error creating user $Sam: $($_.Exception.Message)" -Level "ERROR" -Path $LogPath
}

This ensures that failures are recorded even if the script continues running.

8. Avoiding Sensitive Data in Logs¶

A professional script must never log:

Passwords
Secure strings
Authentication tokens
Personally identifiable information (unless required and approved)

If sensitive data is necessary, it should be masked or omitted.

Example¶

Write-Log -Message "Password provided (masked)" -Level "DEBUG" -Path $LogPath

Security must always take precedence over convenience.

9. Rotating and Managing Log Files¶

Long‑running or frequently executed scripts can generate large logs. A simple rotation strategy prevents logs from growing indefinitely.

Example: rotating logs¶

if (Test-Path $LogPath -and (Get-Item $LogPath).Length -gt 5MB) {
    Rename-Item -Path $LogPath -NewName "$LogPath.$(Get-Date -Format yyyyMMddHHmmss)"
}

This renames the existing log when it exceeds a size threshold.

10. Practical Example: Logging in a Real Script¶

Below is a simplified example showing how logging integrates into a professional script:

param(
    [string]$LogPath = "C:\Logs\UserCreation.log"
)

Write-Log -Message "Script started." -Path $LogPath

try {
    $password = ConvertTo-SecureString "P@ssw0rd" -AsPlainText -Force
    New-ADUser -Name "Alice Kim" -SamAccountName "alice.kim" -AccountPassword $password -Enabled $true
    Write-Log -Message "Created user alice.kim" -Path $LogPath
}
catch {
    Write-Log -Message "Failed to create user: $($_.Exception.Message)" -Level "ERROR" -Path $LogPath
}

Write-Log -Message "Script completed." -Path $LogPath

This example demonstrates:

A clear start and end
Logging of major actions
Error handling with detailed messages
A consistent log format

11. Summary¶

Logging is a fundamental part of writing professional PowerShell scripts. A robust logging strategy ensures that your scripts are:

Transparent
Maintainable
Auditable
Troubleshootable
Safe to run in production

By designing a dedicated logging function, using log levels, avoiding sensitive data, and recording meaningful events, you elevate your scripts from simple automation tools to reliable, enterprise‑ready solutions.