Difference between revisions of "LMD LogTools tutorial"
Line 1: | Line 1: | ||
__TOC__<br> | __TOC__<br> | ||
− | = | + | = LogTools package = |
== Introduction == | == Introduction == |
Revision as of 19:35, 4 October 2009
Contents
LogTools package
Introduction
Any programmer who is capable of writing complex applications is aware of the fact that some parts of code cannot be debugged with an interactive debugger (e.g. system service, threaded code, painting routines etc) or that situations exist, where an interactive debugger is unavailable. Common solution for for such cases is information logging. There many ways of logging - to files, to terminal, to system dialog boxes etc. To make life more simple we implemented a powerful logging system, that allows a developer to concentrate on main application logic instead of writing and debugging his own routines.
Structure of AnyLogger
AnyLogger offer a flexible and extensible set of classes to log useful information. There are four main items: Message, Session, Transport and Manager. Message is container for information that should be logged. Session is class that wrap different information into Message and send it over Transport layer. Transport layer is responsible for physical delivery of Message. And at last but not least - the Manager allows user to create root (default) and user sessions, load/save user sessions and transport parameters. Secondary points are Router and Server (message Collector).
Basic using
Main purpose of this tool package is logging and monitoring actions of application. It should be used when you can't run regular debugger or when it useless - multi-thread application, system services, applications on client site etc.
Сurrent pre-beta version provides basic features only. To start use LogTools in your application you should add LMDLogMessage.pas unit to uses section of your unit, then you'll be able to use LMDLog instance of TLMDLogSession class.
<delphi> uses
..., LMDLogMessage, ...;
...
LMDLog.SendString('Test', 'Hello, World!');
... </delphi>
TLMDLogSession class has methods to send some info into main log - TLMDLogSession.Send*, to watch data in Watch area - TLMDLogSession.Watch* (main different with Send* function that Watch* has just changed value of watched variables, but not add new record)
<delphi> uses
..., LMDLogMessage, ...;
...
while i < 200 do LMDLog.WatchInteger('i', i);
... </delphi>
To logging flow of application, below methods available: TLMDLogSession.Enter*, TLMDLogSession.Leave*. Sample:
<delphi> uses
..., LMDLogMessage, ...;
... function TestFunction: HResult; begin
LMDLog.EnterMethod('TestFunction'); try ... finally LMDLog.SendHResult('Result', Result); LMDLog.LeaveMethod('TestFunction'); end;
end; ... </delphi>
and methods that help to trace of application
<delphi> uses
..., LMDLogMessage, ...;
...
for i := 0 to Count - 1 do begin LMDLog.SendInteger('Iteration', i); b := 20 + i; LMDLog.TouchCounter('Checkpoint'); a := CalcA(b); LMDLog.TouchCounter('Checkpoint'); c := a div 34; LMDLog.ReleaseCounter('Checkpoint'); end;
... </delphi>
To control log storage TLMDLogSession has next methods - TLMDLogSession.ClearLog, TLMDLogSession.ClearWatch and TLMDLogSession.ClearCallStack
TLMDLogSession allow you to control level of you logging messages. It has two properties for it - TLMDLogSession.AllowLogLevel - set minimum log level for messages, TLMDLogSession.DefaultLogLevel - set default log level for messages where level is not set as parameter.
<delphi> uses
..., LMDLogMessage, ...;
...
{$ifdef DEBUG} LMDLog.AllowLogLevel := LogAll; LMDLog.AllowLogLevel := LogAll; {$ELSE} LMDLog.AllowLogLevel := LogFatal; LMDLog.DefaultLogLevel := LogOff; {$ENDIF} for i := 0 to 4 do begin try LMDLog.SendInteger('i', i); a := 5 / i; LMDLog.SendReal('a', a); except on E: EDivideByZero do LMDLog.SendString(LogFatal, 'Error', 'Divide by zero'); end; end;
... </delphi> Logging for 'a' and 'i' will be turned off when DEBUG undefined, but 'Error' will be sent to log in any case.
AnyLogger console application
This logging and monitoring console for LMD Log package. All data that you send from your application are collected and displayed here.
Creating Viewer plugin for AnyLogger console
NB. This API information can be changed before AnyLogger release
AnyLogger console can be extended by pluggable modules (plugins). Plugins based on new package LMD Plugins. Currently you can create plugin to view custom data, that you sent to console, in more obvious form.
To create such plugin you will need LMD Plugins package and uCreatePlugin.pas unit.
<delphi> unit uCreatePlugin;
interface
uses
SysUtils, Forms, LMDPluginManager, LMDPluginImpl;
type
TLMDActionExecutor = class(TObject) public procedure GetCount(const AnAction: ILMDAction; var AResult: ILMDParameter); virtual; stdcall; abstract; procedure GetType(const AnAction: ILMDAction; var AResult: ILMDParameter); virtual; stdcall; abstract; procedure GetIcon(const AnAction: ILMDAction; var AResult: ILMDParameter); virtual; stdcall; abstract; procedure GetName(const AnAction: ILMDAction; var AResult: ILMDParameter); virtual; stdcall; abstract; end;
function CreatePlugin(AExecuter: TLMDActionExecutor; AFormClass: TFormClass): ILMDPlugin;
implementation
function CreatePlugin(AExecuter: TLMDActionExecutor; AFormClass: TFormClass): ILMDPlugin; var
Plugin: TLMDPlugin;
begin
try // Create the plugin Plugin := TLMDPlugin.Create('Author', 'AnyLogger plugin', 0, 1);
// add GetSupportedSubTypesCount action Plugin.AddAction('GetSubTypesCount').OnPerformAction := AExecuter.GetCount; with Plugin.AddAction('GetSubTypeName') do begin with AddParameter('SubType') do ParameterType := ptGUID; OnPerformAction := AExecuter.GetName; end;
with Plugin.AddAction('GetSubType') do begin with AddParameter('Index') do ParameterType := ptInteger; OnPerformAction := AExecuter.GetType; end;
with Plugin.AddAction('GetSubTypeIconIndex') do begin with AddParameter('SubType') do ParameterType := ptGUID; OnPerformAction := AExecuter.GetIcon; end;
// add form into plugin Plugin.AddForm(TLMDDelphiPluginForm.Create('Viewer', AFormClass));
// return the plugin Result := Plugin; except Result := nil; exit; end;
end;
end. </delphi>
uCreatePlugin.pas create TLMDPlugin instance and init with three plugin method "GetSubTypesCount" - returns count of lmdlog message subtypes that will showed by this plugins. Next method is "GetSubTypeName" - returns name of subtype by it's index (0..GetSubTypesCount - 1). "GetSubType" method returns GUID that identificate subtype. And the last method is "GetSubTypeIconIndex" - it returns iconindex to show icon in AnyLogger console by subtype GUID.
So, uCreatePlugin.pas do above basic steps for you. Next, you need to create form with interface ILMDFormWithData, which described in LMDPluginManager unit from LMD Plugins package.
<delphi> { **************************** ILMDFormWithData **************************** }
ILMDFormWithData = interface(IInterface) ['{8999ED41-2791-4471-BFEB-994923CE1CD4}'] procedure SetFormData(AData: Pointer); end;
</delphi>
This interface is needed to fill form with you custom data. AnyLogger Console call SetFormData method with TLMDLogMessage instance as parameter. Here is example of such form:
<delphi>
...
type
TTextForm = class(TForm, ILMDFormWithData) edtText: TElMemo; private { Private declarations } public procedure SetFormData(AData: Pointer); end;
var
TextForm: TTextForm;
implementation
{$R *.dfm}
{ TTextForm }
procedure TTextForm.SetFormData(AData: Pointer); begin
edtText.Text := TLMDLogMessage(AData).MessageValue;
end; ... </delphi>
Next step is creating child class for TLMDActionExecutor from uCreatePlugin.pas and override handlers of plugin methods. Example:
<delphi>
unit intfTextView;
interface
uses
Classes, SysUtils, uCreatePlugin, LMDLogMessage, LMDPluginImpl, LMDPluginManager;
type
TLMDTextActionExecutor = class(TLMDActionExecutor) public procedure GetCount(const AnAction: ILMDAction; var AResult: ILMDParameter); override; stdcall; procedure GetType(const AnAction: ILMDAction; var AResult: ILMDParameter); override; stdcall; procedure GetIcon(const AnAction: ILMDAction; var AResult: ILMDParameter); override; stdcall; procedure GetName(const AnAction: ILMDAction; var AResult: ILMDParameter); override; stdcall; end;
implementation
{ TLMDTextActionExecutor }
procedure TLMDTextActionExecutor.GetCount(const AnAction: ILMDAction; var AResult: ILMDParameter); begin
AResult.AsInteger := 1;
end;
procedure TLMDTextActionExecutor.GetIcon(const AnAction: ILMDAction; var AResult: ILMDParameter); begin
AResult.AsInteger := -1; if IsEqualGUID(AnAction[0].AsGUID, mstString) then AResult.AsInteger := 5;
end;
procedure TLMDTextActionExecutor.GetName(const AnAction: ILMDAction; var AResult: ILMDParameter); begin
if IsEqualGUID(AnAction[0].AsGUID, mstString) then AResult.AsString := 'String';
end;
procedure TLMDTextActionExecutor.GetType(const AnAction: ILMDAction; var AResult: ILMDParameter); begin
case AnAction[0].AsInteger of 0: AResult.AsGUID := mstString; else AResult.AsGUID := mstNone; end;
end;
end. </delphi>
And final step is create Dll project with export function GetLMDPlugin (see LMD Plguins for details).
<delphi>
library TextView;
uses
SysUtils, Classes, Windows, Forms, uCreatePlugin, LMDLogMessage, LMDPluginImpl, LMDPluginManager, frmTextView in 'frmTextView.pas' {TableForm}, intfTextView in 'intfTextView.pas';
{$R *.res}
var
LOldApplication: TApplication;
function GetLMDPlugin(const AHostApplication: TApplication; var APlugin: ILMDPlugin): HRESULT; stdcall; begin
try LOldApplication := Application; Application := AHostApplication;
APlugin := CreatePlugin(TLMDTextActionExecutor.Create, TTextForm); except Result := E_UNEXPECTED; exit; end; Result := S_OK;
end;
procedure DllMain(AReason: integer) ; begin
case AReason of DLL_PROCESS_DETACH: if Assigned(LOldApplication) then Application := LOldApplication; end;
end;
exports
GetLMDPlugin name 'GetLMDPlugin';
begin
LOldApplication := nil; DllProc := @DllMain;
end.
</delphi>
Compile it and copy result dll file to Viewers folder in AnyLogger console installation path.