protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
var cron = WeihanLi.Common.Helpers.Cron.CronExpression.Parse(CronExpression);
var next = cron.GetNextOccurrence();
while (!stoppingToken.IsCancellationRequested && next.HasValue)
{
var now = DateTimeOffset.UtcNow;
if (now >= next)
{
if (ConcurrentAllowed)
{
_ = ProcessAsync(stoppingToken);
next = CronHelper.GetNextOccurrence(CronExpression);
if (next.HasValue)
{
Logger.LogInformation("Next at {next}", next);
}
}
else
{
var firewall = RedisManager.GetFirewallClient($"Job_{GetType().FullName}_{next:yyyyMMddHHmmss}", TimeSpan.FromMinutes(3));
if (await firewall.HitAsync())
{
// 执行 job
await ProcessAsync(stoppingToken);
next = CronHelper.GetNextOccurrence(CronExpression);
if (next.HasValue)
{
Logger.LogInformation("Next at {next}", next);
var delay = next.Value - DateTimeOffset.UtcNow;
if (delay > TimeSpan.Zero)
{
await Task.Delay(delay, stoppingToken);
}
}
}
else
{
Logger.LogInformation("正在执行 job，不能重复执行");
next = CronHelper.GetNextOccurrence(CronExpression);
if (next.HasValue)
{
await Task.Delay(next.Value - DateTimeOffset.UtcNow, stoppingToken);
}
}
}
}
else
{
// needed for graceful shutdown for some reason.
// 1000ms so it doesn't affect calculating the next
// cron occurence (lowest possible: every second)
await Task.Delay(next.Value - DateTimeOffset.UtcNow, stoppingToken);
}
}
}
public static void MainTest()
{
// http://www.quartz-scheduler.org/documentation/quartz-2.3.0/tutorials/crontrigger.html
var nextTickUtc = CronHelper.GetNextOccurrence("0 15 10 * * ?");
var nextTickLocal = CronHelper.GetNextOccurrence("0 15 10 * * ?", TimeZoneInfo.Local);
Console.WriteLine($"@utc next tick: {nextTickUtc.GetValueOrDefault().DateTime.ToStandardTimeString()} {Environment.NewLine} local next tick:{nextTickLocal.GetValueOrDefault().DateTime.ToStandardTimeString()}");
var nextTicks = CronHelper.GetNextOccurrences("0 15 10-20 * * ?", TimeSpan.FromHours(6), TimeZoneInfo.Local).Take(5).ToArray();
foreach (var tick in nextTicks)
{
Console.WriteLine(tick.DateTime.ToStandardTimeString());
}
}
