/// <summary>
/// For schedules with an occurrence more frequent than 1 minute, we disable schedule monitoring.
/// </summary>
/// <param name="cronSchedule">The cron schedule to check.</param>
/// <returns>True if monitoring should be disabled, false otherwise.</returns>
internal static bool ShouldDisableScheduleMonitor(CronSchedule cronSchedule, DateTime now)
{
// take the original expression minus the seconds portion
string expression = cronSchedule.InnerSchedule.ToString();
var expressions = expression.Split(' ');
// If any of the minute or higher fields contain non-wildcard expressions
// the schedule can be longer than 1 minute. I.e. the only way for all occurrences
// to be less than or equal to a minute is if all these fields are wild ("* * * * *").
bool hasNonSecondRestrictions = !expressions.Skip(1).All(p => p == "*");
if (!hasNonSecondRestrictions)
{
// If to here, we know we're dealing with a schedule of the form X * * * * *
// so we just need to consider the seconds expression to determine if it occurs
// more frequently than 1 minute.
// E.g. an expression like */10 * * * * * occurs every 10 seconds, while an
// expression like 0 * * * * * occurs exactly once per minute.
DateTime[] nextOccurrences = cronSchedule.InnerSchedule.GetNextOccurrences(now, now + TimeSpan.FromMinutes(1)).ToArray();
if (nextOccurrences.Length > 1)
{
// if there is more than one occurrence due in the next minute,
// assume that this is a sub-minute constant schedule and disable
// persistence
return(true);
}
}
return(false);
}
/// <summary>
/// Constructs a new instance based on the schedule expression passed in./>
/// </summary>
/// <param name="expression">A schedule expression. This can either be a crontab expression
/// <a href="http://en.wikipedia.org/wiki/Cron#CRON_expression"/> or a <see cref="TimeSpan"/> string.</param>
public TimerTriggerAttribute(string expression)
{
CronSchedule cronSchedule = null;
if (CronSchedule.TryCreate(expression, out cronSchedule))
{
Schedule = cronSchedule;
DateTime[] nextOccurrences = cronSchedule.InnerSchedule.GetNextOccurrences(DateTime.Now, DateTime.Now + TimeSpan.FromMinutes(1)).ToArray();
if (nextOccurrences.Length > 1)
{
// if there is more than one occurrence due in the next minute,
// assume that this is a sub-minute constant schedule and disable
// persistence
UseMonitor = false;
}
else
{
UseMonitor = true;
}
}
else
{
TimeSpan periodTimespan = TimeSpan.Parse(expression);
Schedule = new ConstantSchedule(periodTimespan);
// for very frequent constant schedules, we want to disable persistence
UseMonitor = periodTimespan.TotalMinutes >= 1;
}
}
internal static TimerSchedule Create(TimerTriggerAttribute attribute, INameResolver nameResolver)
{
TimerSchedule schedule = null;
if (!string.IsNullOrEmpty(attribute.ScheduleExpression))
{
string resolvedExpression = nameResolver.ResolveWholeString(attribute.ScheduleExpression);
CronSchedule cronSchedule = null;
if (CronSchedule.TryCreate(resolvedExpression, out cronSchedule))
{
schedule = cronSchedule;
DateTime[] nextOccurrences = cronSchedule.InnerSchedule.GetNextOccurrences(DateTime.Now, DateTime.Now + TimeSpan.FromMinutes(1)).ToArray();
if (nextOccurrences.Length > 1)
{
// if there is more than one occurrence due in the next minute,
// assume that this is a sub-minute constant schedule and disable
// persistence
attribute.UseMonitor = false;
}
else if (!attribute.UseMonitor.HasValue)
{
// if the user hasn't specified a value
// set to true
attribute.UseMonitor = true;
}
}
else
{
TimeSpan periodTimespan = TimeSpan.Parse(resolvedExpression);
schedule = new ConstantSchedule(periodTimespan);
if (periodTimespan.TotalMinutes < 1)
{
// for very frequent constant schedules, we want to disable persistence
attribute.UseMonitor = false;
}
else if (!attribute.UseMonitor.HasValue)
{
// if the user hasn't specified a value
// set to true
attribute.UseMonitor = true;
}
}
}
else
{
schedule = (TimerSchedule)Activator.CreateInstance(attribute.ScheduleType);
if (!attribute.UseMonitor.HasValue)
{
// if the user hasn't specified a value
// set to true
attribute.UseMonitor = true;
}
}
return(schedule);
}
internal static bool TryCreate(string cronExpression, out CronSchedule cronSchedule)
{
cronSchedule = null;
CrontabSchedule.ParseOptions options = new CrontabSchedule.ParseOptions()
{
IncludingSeconds = true
};
CrontabSchedule crontabSchedule = CrontabSchedule.TryParse(cronExpression, options);
if (crontabSchedule != null)
{
cronSchedule = new CronSchedule(crontabSchedule);
return true;
}
return false;
}
internal static bool TryCreate(string cronExpression, out CronSchedule cronSchedule)
{
cronSchedule = null;
CrontabSchedule.ParseOptions options = new CrontabSchedule.ParseOptions()
{
IncludingSeconds = true
};
CrontabSchedule crontabSchedule = CrontabSchedule.TryParse(cronExpression, options);
if (crontabSchedule != null)
{
cronSchedule = new CronSchedule(crontabSchedule);
return(true);
}
return(false);
}
internal static bool TryCreate(string cronExpression, out CronSchedule cronSchedule)
{
cronSchedule = null;
if (cronExpression != null)
{
var options = CreateParseOptions(cronExpression);
CrontabSchedule crontabSchedule = CrontabSchedule.TryParse(cronExpression, options);
if (crontabSchedule != null)
{
cronSchedule = new CronSchedule(crontabSchedule);
return(true);
}
}
return(false);
}
public void GetNextOccurrence_ThreeDaySchedule_MultipleScheduleIterations()
{
// 11:59AM on Mondays, Tuesdays, Wednesdays, Thursdays and Fridays
CronSchedule schedule = new CronSchedule("0 59 11 * * 1-5");
DateTime now = new DateTime(2015, 5, 23, 9, 0, 0);
TimeSpan expectedTime = new TimeSpan(11, 59, 0);
for (int i = 1; i <= 5; i++)
{
DateTime nextOccurrence = schedule.GetNextOccurrence(now);
Assert.Equal((DayOfWeek)i, nextOccurrence.DayOfWeek);
Assert.Equal(expectedTime, nextOccurrence.TimeOfDay);
now = nextOccurrence + TimeSpan.FromSeconds(1);
}
}
internal static TimerSchedule Create(TimerTriggerAttribute attribute, INameResolver nameResolver)
{
TimerSchedule schedule = null;
if (!string.IsNullOrEmpty(attribute.ScheduleExpression))
{
string resolvedExpression = nameResolver.ResolveWholeString(attribute.ScheduleExpression);
CronSchedule cronSchedule = null;
TimeSpan periodTimespan;
if (CronSchedule.TryCreate(resolvedExpression, out cronSchedule))
{
schedule = cronSchedule;
DateTime[] nextOccurrences = cronSchedule.InnerSchedule.GetNextOccurrences(DateTime.Now, DateTime.Now + TimeSpan.FromMinutes(1)).ToArray();
if (nextOccurrences.Length > 1)
{
// if there is more than one occurrence due in the next minute,
// assume that this is a sub-minute constant schedule and disable
// persistence
attribute.UseMonitor = false;
}
}
else if (TimeSpan.TryParse(resolvedExpression, out periodTimespan))
{
schedule = new ConstantSchedule(periodTimespan);
if (periodTimespan.TotalMinutes < 1)
{
// for very frequent constant schedules, we want to disable persistence
attribute.UseMonitor = false;
}
}
else
{
throw new ArgumentException("The schedule expression was not recognized as a valid cron expression or timespan string.");
}
}
else
{
schedule = (TimerSchedule)Activator.CreateInstance(attribute.ScheduleType);
}
return(schedule);
}
internal static TimerSchedule Create(TimerTriggerAttribute attribute, INameResolver nameResolver, ILogger logger)
{
TimerSchedule schedule = null;
if (!string.IsNullOrEmpty(attribute.ScheduleExpression))
{
string resolvedExpression = nameResolver.ResolveWholeString(attribute.ScheduleExpression);
if (CronSchedule.TryCreate(resolvedExpression, out CronSchedule cronSchedule))
{
schedule = cronSchedule;
if (attribute.UseMonitor && ShouldDisableScheduleMonitor(cronSchedule, DateTime.Now))
{
logger.LogDebug("UseMonitor changed to false based on schedule frequency.");
attribute.UseMonitor = false;
}
}
else if (TimeSpan.TryParse(resolvedExpression, out TimeSpan periodTimespan))
{
schedule = new ConstantSchedule(periodTimespan);
if (attribute.UseMonitor && periodTimespan.TotalMinutes < 1)
{
// for very frequent constant schedules, we want to disable persistence
logger.LogDebug("UseMonitor changed to false based on schedule frequency.");
attribute.UseMonitor = false;
}
}
else
{
throw new ArgumentException(string.Format("The schedule expression '{0}' was not recognized as a valid cron expression or timespan string.", resolvedExpression));
}
}
else
{
schedule = (TimerSchedule)Activator.CreateInstance(attribute.ScheduleType);
}
return(schedule);
}
public void ToString_ReturnsExpectedValue()
{
CronSchedule schedule = new CronSchedule("0 59 11 * * 1-5");
Assert.Equal("Cron: '0 59 11 * * 1-5'", schedule.ToString());
}
