Gumby.Log.psm1
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# abstain from using module Assert here as it might use the Log module enum LogMessageType { Comment Warning Error Success Failure BeginSection EndSection } # Design considerations: # I want to enable the use of Log calls without having to worry about performance. Therefore, Log # calls in the absence of log listeners should have a negligible overhead. # # Should taking of time stamps be centralized in the log dispatcher? # I think not for not all log outputs might utilize them (e.g. a file-based listener might while a # screen-based listener might not). # # Should verbosity-gating be centralized in the log dispatcher? # I think not. It is conceivable to have a run with multiple listeners that operate with different # verbosity settings (e.g. a screen-based listener that shows only "important" output while a # file-based listener logs everything). # # Should the log dispatcher keep track of nesting depth (sections)? # I think not for not all log outputs might utilize them (e.g. an XML-based log listener might # represent sections with respective tags rather than through indentation). # Would 'Trace' be a better name? class Log { static [void] Comment([string] $Message) { [Log]::DispatchMessage([LogMessageType]::Comment, $Message) } static [void] Trace([string] $Message) { [Log]::DispatchMessage([LogMessageType]::Comment, $Message) } static [void] Warning([string] $Message) { [Log]::DispatchMessage([LogMessageType]::Warning, $Message) ++[Log]::_warningCount } static [void] Error([string] $Message) { [Log]::DispatchMessage([LogMessageType]::Error, $Message) ++[Log]::_errorCount } static [void] Success([string] $Message) { [Log]::DispatchMessage([LogMessageType]::Success, $Message) ++[Log]::_successCount } static [void] Failure([string] $Message) { [Log]::DispatchMessage([LogMessageType]::Failure, $Message) ++[Log]::_failureCount } static [void] BeginSection([string] $Message) { [Log]::DispatchMessage([LogMessageType]::BeginSection, $Message) } static [void] EndSection([string] $Message) { [Log]::DispatchMessage([LogMessageType]::EndSection, $Message) } static hidden [void] DispatchMessage([LogMessageType] $MessageType, [string] $Message) { foreach ($l in [Log]::Listeners) { $l.ProcessMessage($MessageType, $Message) } } static [uint32] WarningCount() { return [Log]::_warningCount } static [uint32] ErrorCount() { return [Log]::_errorCount } static [uint32] SuccessCount() { return [Log]::_successCount } static [uint32] FailureCount() { return [Log]::_failureCount } static [void] Reset() { [Log]::_errorCount = 0 [Log]::_warningCount = 0 [Log]::_successCount = 0 [Log]::_failureCount = 0 } # ArrayList over standard array for mutability static [System.Collections.ArrayList] $Listeners = [System.Collections.ArrayList]::new() static hidden [uint32] $_warningCount = 0 static hidden [uint32] $_errorCount = 0 static hidden [uint32] $_successCount = 0 static hidden [uint32] $_failureCount = 0 } class LogListenerBase { [void] ProcessMessage([LogMessageType] $MessageType, [string] $Message) { throw "calling abstract message" } } class LogObserver : LogListenerBase{ LogObserver([scriptblock] $onProcessMessage) { $this.OnProcessMessage = $onProcessMessage } [void] ProcessMessage([LogMessageType] $MessageType, [string] $Message) { $this.OnProcessMessage.Invoke($MessageType, $Message) } hidden [scriptblock] $OnProcessMessage } class FileLogListener : LogListenerBase { FileLogListener([string] $fileName) { $this._fileName = $fileName } [void] ProcessMessage([LogMessageType] $messageType, [string] $message) { if ($messageType -eq [LogMessageType]::EndSection) { if ($this._nestingLevel -eq 0) { throw "mismatching log sections" } --$this._nestingLevel } Write-Output ("{0,-14} {1}{2}: {3}" -f (Get-Date).ToString("HH:mm:ss.FFFFF"), <# indent #> (" " * 4 * $this._nestingLevel), [FileLogListener]::GetMessageTypeString($messageType), $message ) >> $this._fileName if ($messageType -eq [LogMessageType]::BeginSection) { ++$this._nestingLevel } } static hidden [string] GetMessageTypeString([LogMessageType] $messageType) { switch ($messageType) { ([LogMessageType]::Comment) { return "COMMENT" } ([LogMessageType]::Warning) { return "WARNING" } ([LogMessageType]::Error) { return "ERROR" } ([LogMessageType]::Success) { return "SUCCESS" } ([LogMessageType]::Failure) { return "FAILURE" } ([LogMessageType]::BeginSection) { return "BEGIN" } ([LogMessageType]::EndSection) { return "END" } } throw "unknown message type '$messageType'" } hidden [string] $_fileName hidden [uint32] $_nestingLevel = 0 } class ConsoleLogListener : LogListenerBase { [void] ProcessMessage([LogMessageType] $MessageType, [string] $Message) { switch ($MessageType) { ([LogMessageType]::Warning) { Write-Host -ForegroundColor Yellow $Message } ([LogMessageType]::Error) { Write-Host -ForegroundColor Red $Message } ([LogMessageType]::Success) { Write-Host -ForegroundColor Green $Message } ([LogMessageType]::Failure) { Write-Host -ForegroundColor Red $Message } } } } class LogInterceptor : LogListenerBase { LogInterceptor([scriptblock] $onProcessMessage) { $this.onProcessMessage = $onProcessMessage $this.listeners = [Log]::Listeners [Log]::Listeners = [System.Collections.ArrayList]::new(@($this)) } [void] ProcessMessage([LogMessageType] $MessageType, [string] $Message) { $this.onProcessMessage.Invoke($this, $MessageType, $Message) } [void] DispatchMessage([LogMessageType] $MessageType, [string] $Message) { foreach ($l in $this.listeners) { $l.ProcessMessage($MessageType, $Message) } } [void] Dispose() { [Log]::Listeners = $this.listeners } hidden [System.Collections.ArrayList] $listeners hidden [scriptblock] $onProcessMessage } |