NGINX for Service Fabric

NginxWrapper.cs

internal sealed class NginxWrapper : StatelessService
{
    public NginxWrapper(StatelessServiceContext context) : base(context) { }
    protected override async Task RunAsync(CancellationToken cancellationToken)
    {
        // listen to changes in configuration
        Context.CodePackageActivationContext.ConfigurationPackageModifiedEvent += OnConfigurationPackageModified;
        ServiceEventSource.Current.ServiceMessage(Context, "Service started. Configuration changes listener registered");
        while (true)
        {
            // if cancellation has been requested, attempt shutdown gracefully but force if it fails
            if (cancellationToken.IsCancellationRequested)
            {
                ServiceEventSource.Current.ServiceMessage(Context, "Cancellation requested. Graceful shutdown started.");
                GracefulShutdown(); // attempt graceful shutdown
                // gracefully shutdown the process within 5 seconds
                for (var t = 0; t < 5; t++)
                {
                    if (!IsRunning) break; // stop looping if it is no longer running
                    await Task.Delay(TimeSpan.FromSeconds(1));
                }
                // if the process is stil running forcefully close
                if (IsRunning) KillProcesses();
                return; // nothing more todo
            }
            // ensure the process is still running incase it had been mistakenly dropped
            if (!IsRunning)
            {
                ServiceEventSource.Current.ServiceMessage(
                    Context,
                    "Either the process was manually stopped or had not be started. Starting the process ...");
                SetupAndValidatePaths();
                StartProcess();
            }
            // wait a little while before working to prevent over tasking the cpu
            await Task.Delay(TimeSpan.FromSeconds(5));
        }
    }
    private string ConfigurationFilePath { get; set; }
    private string ExecutableFilePath { get; set; }
    private string RunningProcessName { get; set; }
    private bool IsRunning => !string.IsNullOrWhiteSpace(RunningProcessName) && Process.GetProcessesByName(RunningProcessName).Any();
    private void OnConfigurationPackageModified(object sender, PackageModifiedEventArgs<ConfigurationPackage> e)
    {
        ServiceEventSource.Current.ServiceMessage(Context, "Configuration package was changed. Process shall be restarted");
        GracefulShutdown();
        KillProcesses(); // kill any pending proceses
        SetupAndValidatePaths();
        StartProcess();
    }
    private void SetupAndValidatePaths()
    {
        var configPackage = Context.CodePackageActivationContext.GetConfigurationPackageObject("Config");
        var parameters = configPackage.Settings.Sections["Nginx"].Parameters;
        var configurationFileName = parameters["ConfigurationFileName"].Value;
        var executableFileName = parameters["ExecutableFileName"].Value;
        var codePackageName = Context.CodePackageActivationContext.CodePackageName;
        ExecutableFilePath = Path.Combine(
            Context.CodePackageActivationContext.GetCodePackageObject(codePackageName).Path,
            executableFileName);
        ConfigurationFilePath = Path.Combine(
            configPackage.Path,
            configurationFileName);
        ServiceEventSource.Current.ServiceMessage(
            Context,
            "Setting up service with. {0}={1} and {2}={3}",
            nameof(ConfigurationFilePath),
            ConfigurationFilePath,
            nameof(ExecutableFilePath),
            ExecutableFilePath);
        if (!File.Exists(ExecutableFilePath))
            throw new FileNotFoundException("The specified executable file must exist", ExecutableFilePath);
        if (!File.Exists(ConfigurationFilePath))
            throw new FileNotFoundException("The specified configuration file must exist", ConfigurationFilePath);
    }
    private void KillProcesses()
    {
        if (!string.IsNullOrWhiteSpace(RunningProcessName))
        {
            var processes = Process.GetProcessesByName(RunningProcessName);
            ServiceEventSource.Current.ServiceMessage(
                Context,
                "Found {0} processes with name {1} to forcefully close.",
                processes.Length,
                RunningProcessName);
            foreach (var p in processes)
            {
                ServiceEventSource.Current.ServiceMessage(Context, "Killing process with Id: {0}", p.Id);
                p.Kill();
            }
        }
    }
    private void StartProcess() => LaunchProcess("-c " + ConfigurationFilePath);
    private void GracefulShutdown() => LaunchProcess("-c " + ConfigurationFilePath + " -s quit");
    private void LaunchProcess(string arguments)
    {
        var process = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = ExecutableFilePath,
                WorkingDirectory = Path.GetDirectoryName(ExecutableFilePath),
                UseShellExecute = false,
                Arguments = arguments,
            },
        };
        ServiceEventSource.Current.ServiceMessage(
            Context,
            "Starting process {0} at {1} with arguments {2}",
            Path.GetFileName(process.StartInfo.FileName),
            process.StartInfo.FileName,
            process.StartInfo.Arguments);
        process.Start();
        RunningProcessName = process.ProcessName;
        ServiceEventSource.Current.ServiceMessage(Context, "Service started with name: {0}", RunningProcessName);
    }
}