C# – the most reliable way to create a custom event log and event source during the installation of a .Net Service

cevent-logeventlog-sourcenetwindows-services

I am having difficulty reliably creating / removing event sources during the installation of my .Net Windows Service.

Here is the code from my ProjectInstaller class:

// Create Process Installer
ServiceProcessInstaller spi = new ServiceProcessInstaller();
spi.Account = ServiceAccount.LocalSystem;

// Create Service
ServiceInstaller si = new ServiceInstaller();
si.ServiceName = Facade.GetServiceName();
si.Description = "Processes ...";
si.DisplayName = "Auto Checkout";
si.StartType = ServiceStartMode.Automatic;

// Remove Event Source if already there
if (EventLog.SourceExists("AutoCheckout"))
    EventLog.DeleteEventSource("AutoCheckout");

// Create Event Source and Event Log     
EventLogInstaller log = new EventLogInstaller();
log.Source = "AutoCheckout";
log.Log = "AutoCheckoutLog";

Installers.AddRange(new Installer[] { spi, si, log });

The facade methods referenced just return the strings for the name of the log, service, etc.

This code works most of the time, but recently after installing I started getting my log entries showing up in the Application Log instead of the custom log. And the following errors are in the log as well:

The description for Event ID ( 0 ) in Source ( AutoCheckout ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details.

For some reason it either isn't properly removing the source during the uninstall or it isn't creating it during the install.

Any help with best practices here is appreciated.

Thanks!

In addition, here is a sample of how I am writing exceptions to the log:

// Write to Log
EventLog.WriteEntry(Facade.GetEventLogSource(), errorDetails, EventLogEntryType.Error, 99);

Regarding stephbu's answer: The recommended path is an installer script and installutil, or a Windows Setup routine.

I am using a Setup Project, which performs the installation of the service and sets up the log. Whether I use the installutil.exe or the windows setup project I believe they both call the same ProjectInstaller class I show above.

I see how the state of my test machine could be causing the error if the log isn't truly removed until rebooting. I will experiment more to see if that solves the issue.

Edit:
I'm interested in a sure fire way to register the source and the log name during the installation of the service. So if the service had previously been installed, it would remove the source, or reuse the source during subsequent installations.

I haven't yet had an opportunity to learn WiX to try that route.

Best Answer

The ServiceInstaller class automatically creates an EventLogInstaller and puts it inside its own Installers collection.

Try this code:

ServiceProcessInstaller serviceProcessInstaller = new ServiceProcessInstaller();
serviceProcessInstaller.Password = null;
serviceProcessInstaller.Username = null;
serviceProcessInstaller.Account = ServiceAccount.LocalSystem;

// serviceInstaller
ServiceInstaller serviceInstaller = new ServiceInstaller();
serviceInstaller.ServiceName = "MyService";
serviceInstaller.DisplayName = "My Service";
serviceInstaller.StartType = ServiceStartMode.Automatic;
serviceInstaller.Description = "My Service Description";
// kill the default event log installer
serviceInstaller.Installers.Clear(); 

// Create Event Source and Event Log     
EventLogInstaller logInstaller = new EventLogInstaller();
logInstaller.Source = "MyService"; // use same as ServiceName
logInstaller.Log = "MyLog";

// Add all installers
this.Installers.AddRange(new Installer[] {
   serviceProcessInstaller, serviceInstaller, logInstaller
});

UPDATE

As of 8/1/2014, the article I linked to above is still active, but the blog hasn't been updated in a while. That makes me worry that eventually it might disappear, and with it, the advocated solution. I'm reproducing the content of the article here for posterity. The words belong solely to the blog owner at Sanity Free Coding.

Today I wanted to refactor some code that prohibited my application from running multiple instances of itself.

Previously I had use System.Diagnostics.Process to search for an instance of my myapp.exe in the process list. While this works, it brings on a lot of overhead, and I wanted something cleaner.

Knowing that I could use a mutex for this (but never having done it before) I set out to cut down my code and simplify my life.

In the class of my application main I created a static named Mutex:

static class Program
{
    static Mutex mutex = new Mutex(true, "{8F6F0AC4-B9A1-45fd-A8CF-72F04E6BDE8F}");
    [STAThread]
    ...
}

Having a named mutex allows us to stack synchronization across multiple threads and processes which is just the magic I'm looking for.

Mutex.WaitOne has an overload that specifies an amount of time for us to wait. Since we're not actually wanting to synchronizing our code (more just check if it is currently in use) we use the overload with two parameters: Mutex.WaitOne(Timespan timeout, bool exitContext). Wait one returns true if it is able to enter, and false if it wasn't. In this case, we don't want to wait at all; If our mutex is being used, skip it, and move on, so we pass in TimeSpan.Zero (wait 0 milliseconds), and set the exitContext to true so we can exit the synchronization context before we try to aquire a lock on it. Using this, we wrap our Application.Run code inside something like this:

static class Program
{
    static Mutex mutex = new Mutex(true, "{8F6F0AC4-B9A1-45fd-A8CF-72F04E6BDE8F}");
    [STAThread]
    static void Main() {
        if(mutex.WaitOne(TimeSpan.Zero, true)) {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
            mutex.ReleaseMutex();
        } else {
            MessageBox.Show("only one instance at a time");
        }
    }
}

So, if our app is running, WaitOne will return false, and we'll get a message box.

Instead of showing a message box, I opted to utilize a little Win32 to notify my running instance that someone forgot that it was already running (by bringing itself to the top of all the other windows). To achieve this I used PostMessage to broadcast a custom message to every window (the custom message was registered with RegisterWindowMessage by my running application, which means only my application knows what it is) then my second instance exits. The running application instance would receive that notification and process it. In order to do that, I overrode WndProc in my main form and listened for my custom notification. When I received that notification I set the form's TopMost property to true to bring it up on top.

Here is what I ended up with:

Program.cs

static class Program
{
    static Mutex mutex = new Mutex(true, "{8F6F0AC4-B9A1-45fd-A8CF-72F04E6BDE8F}");
    [STAThread]
    static void Main() {
        if(mutex.WaitOne(TimeSpan.Zero, true)) {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
            mutex.ReleaseMutex();
        } else {
            // send our Win32 message to make the currently running instance
            // jump on top of all the other windows
            NativeMethods.PostMessage(
                (IntPtr)NativeMethods.HWND_BROADCAST,
                NativeMethods.WM_SHOWME,
                IntPtr.Zero,
                IntPtr.Zero);
        }
    }
}

NativeMethods.cs

// this class just wraps some Win32 stuff that we're going to use
internal class NativeMethods
{
    public const int HWND_BROADCAST = 0xffff;
    public static readonly int WM_SHOWME = RegisterWindowMessage("WM_SHOWME");
    [DllImport("user32")]
    public static extern bool PostMessage(IntPtr hwnd, int msg, IntPtr wparam, IntPtr lparam);
    [DllImport("user32")]
    public static extern int RegisterWindowMessage(string message);
}

Form1.cs (front side partial)

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    protected override void WndProc(ref Message m)
    {
        if(m.Msg == NativeMethods.WM_SHOWME) {
            ShowMe();
        }
        base.WndProc(ref m);
    }
    private void ShowMe()
    {
        if(WindowState == FormWindowState.Minimized) {
            WindowState = FormWindowState.Normal;
        }
        // get our current "TopMost" value (ours will always be false though)
        bool top = TopMost;
        // make our form jump to the top of everything
        TopMost = true;
        // set it back to whatever it was
        TopMost = top;
    }
}

How to create an event log source using WiX

Wix has out-of-the-box support for creating event log sources.

Assuming you use Wix 3, you first need to add a reference to WixUtilExtension to either your Votive project or the command line. You can then add an EventSource element under a component :

<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"
    xmlns:util="http://schemas.microsoft.com/wix/UtilExtension">

    <Component ...>
        ...
        <util:EventSource Log="Application" Name="*source name*"
           EventMessageFile="*path to message file*"/>
        ...
    </Component>

If this is a .NET project, you can use EventLogMessages.dll in the framework directory as the message file.

Best Answer

Related Solutions

C# – the correct way to create a single-instance WPF application

UPDATE

How to create an event log source using WiX

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