protected override async Task ExecuteAsync(CancellationToken token)
{
// Create a token that can be cancelled to stop all running tasks
var tokenSource = CancellationTokenSource.CreateLinkedTokenSource(token);
// Execute startup activities and upon success send a startup signal
await SendStartedSignalAsync(tokenSource.Token).ConfigureAwait(false);
// Start sending liveness signal periodically
var signalParallelTask = SendAliveSignalAsync(TimeSpan.FromSeconds(_probeConfiguration.LivenessSignalIntervalSeconds), tokenSource.Token);
// Paralllelly execute background worker's jobs
var workerParallelTask = _serviceImplementation.ExecuteAsync(tokenSource.Token);
// If liveness or worker job throws exception or runs to completion then cancel everything and exit the program.
var continuationTask = await Task.WhenAny(signalParallelTask, workerParallelTask).ConfigureAwait(false);
// Awaiting on task returned by Task.WhenAny() bubbles exceptions in inner tasks
await continuationTask.ConfigureAwait(false);
// If any one of then run to completion then cancel the other
await continuationTask.ContinueWith(t => tokenSource.Cancel()).ConfigureAwait(false);
// Although all tasks will finish by now, background service will not cause the host to terminate.
// You will have to implement IApplicationLifetime for that which may not make sense if there are multiple IHostedService implemented.
// But, since kubernetes liveness probes are enabled, absence of alive.signal file will cause service to reboot.
}
