What is the best practice for flagging and reacting to build failures during execution?

[andre-wells]

Let's say that if a build fails, I want to send a slack message and rename the output folder to something like output_failed.

So far I've identified two ways of handling a build failure in a generic manner

Make use of OnBuildFinished

Within this routine, I can test the build.IsSuccessful property to see if I need to take action. Credit to Erik Heemskerk, I can define a custom attribute which will let me assess this value (which makes things a bit neater and reusable).

public class NotifyFailureAttribute : BuildExtensionAttributeBase, IOnBuildFinished
{
    public void OnBuildFinished(NukeBuild build)
    {
        if(!build.IsSuccessful)
        {
            Serilog.Log.Fatal("Build failed: this is the attribute way of handling it but we don't have a great way to await this call :|");
        }
    }
}

[CheckBuildProjectConfigurations]
[ShutdownDotNetAfterServerBuild]
[NotifyFailure]
class Build : NukeBuild
{
    // remaining code

Pros:

• This gets called regardless of how Nuke determined execution so it's fairly reliable.
  Cons:
• However, this method doesn't let me await calls properly. I could use async void but tasks can terminate early as the build finishes. I'd need to call these methods synchronously.
• As it's not a target, I don't get the "step" shown nicely in the log (although I could always show more logs)

Make use of a Target that always runs

I'm familiar with conditions like ProceedAfterFailure and AssuredAfterFailure so I can author Targets to run despite a build or a test Target failing.

Target NotifyOfResult => _ => _
        .AssuredAfterFailure() //always run        
        .DependsOn(Publish)
        .Executes(async () =>
        {
            await Task.Delay(1000); // test async

            if(_buildHasFailed) // set by earlier action through try/catch
              Serilog.Log.Fatal("TARGET Oh noes! The build failed!");
        });

Pros:

• Allows me to await tasks.
• Gets nicely logged in the steps executed.
  Cons:
• I need to track the build failure in a stateful way.
• Try/Catch becomes a necessity in other Targets.
• The Target will always need to be scheduled for execution.

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Is there a common way to define a target such as with a conditional such as "ReportFailure" which only fires in the event of a failed target?