Debugging C# Custom Installer Classes

Question

I have written an installation class that extends Installer and overrides afterInstall, but I'm getting a null pointer exception. How can I got about debugging my class?

Answer 1

build a VM, install Visual studio, make a copy of it (or create a differencing Virtual HDD) and run the installer under the debugger under the VM.

That is what I would do (but I'm no expert).

Answer 2

attach the installer process to Visual studio in Debug->Processes->Attach or CTRL + ALT + P set the breakpoint and you should be able to go

Answer 3

Something that is handy for hard to debug sections of code is

System.Diagnostics.Debugger.Break()

Will throw a breakpoint caught by any installed debugger (VStudio, WinDbg, Remote debugger etc...).

Use it to debug really tricky areas where regular F5+Go or "Attach to Process" is difficult or impossible to perform, some examples include:

• short-lived processes
• time-sensitive processes
• breaking into spawned sub-processes
• installers
• service stop/start
• distributed systems

Answer 4

I use EventLog.WriteEntry("source", "message"), and check the EventLog when installing. Maybe not optimal, but works for me :)

Answer 5

The best way I've found is to write a unit test, and new up and initialize your installer class from your unit test:

[TestClass] public class InstallerTest {
[TestMethod]
public void InstallTest() {
  // substitute with your installer component here
  DataWarehouseInstall installer = new DataWarehouseInstall();

  string assemblyDirectory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

  string installLogFilePath = Path.Combine(assemblyDirectory, "install.log");
  installer.Context = new System.Configuration.Install.InstallContext(installLogFilePath, null);      

  // Refactor to set any parameters for your installer here
  installer.Context.Parameters.Add("Server", ".");
  //installer.Context.Parameters.Add("User", "");
  //installer.Context.Parameters.Add("Password", "");
  installer.Context.Parameters.Add("DatabaseName", "MyDatabaseInstallMsiTest");
  //installer.Context.Parameters.Add("DatabasePath", "");

  // Our test isn't injecting any save state so we give a default instance for the stateSaver
  installer.Install(new Hashtable());
} }

At least then it takes advantage of the IDE tooling better. This is especially helpful for very large installers with LOTS of components. Then you can also create ordered unit tests and run them in sequence to mimic your installer during debug or your automated builds.

Another tip would be general SOLID/GRASS software principles...develop in neat/thin layers, keeping your actual "custom action" installer logic very simple and instead call into any reusable API stuff you have that is specific to your installer(s), just as we are used to with UI development. (The installer is just another UI anyway.) This is especially key if your goal is to have a certain UI experience shared across all installers of your products.

Answer 6

You can also use the installUtil.exe utility to test your installer component.

In case you created a c# class assembly with your Installer class, Change your debug settings to start the external program 'C:\Windows\Microsoft.NET\Framework\v2.0.50727\InstallUtil.exe' and enter your commandline arguments accordingly (e.g. /Args=myargument "path to the assembly")

As last set your breakpoints, press f5 and you're set to debug your code. --paralax

Answer 7

I use the following class to write a simple log into the target directory. In my opinion, it's easier than trying to use the Visual Studio debugger.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace MyCompany.Deployment
{
    /// <summary>
    /// Enables a quick and easy method of debugging custom actions.
    /// </summary>
    class LogFile
    {
        const string FileName = "MyCompany.Deployment.log";
        readonly string _filePath;

        public LogFile(string primaryOutputPath)
        {
            var dir = Path.GetDirectoryName(primaryOutputPath);
            _filePath = Path.Combine(dir, FileName);
        }

        public void Print(Exception ex)
        {
            File.AppendAllText(_filePath, "Error: " + ex.Message + Environment.NewLine +
                    "Stack Trace: " + Environment.NewLine + ex.StackTrace + Environment.NewLine);
        }

        public void Print(string format, params object[] args)
        {
            var text = String.Format(format, args) + Environment.NewLine;

            File.AppendAllText(_filePath, text);
        }

        public void PrintLine() { Print(""); }
    }
}