LaquaiLib.Threading.CronTimer 0.1.0

LaquaiLib.Threading.CronTimer

A PeriodicTimer-like timer driven by one or more cron expressions instead of a fixed interval. Backed by Cronos for ultra-fast, lightweight cron parsing.

Overview

CronTimer fires at the next occurrence dictated by any of the provided cron expressions. When multiple expressions are supplied the timer fires at whichever is earliest. Both standard 5-field (min hour dom mon dow) and 6-field (sec min hour dom mon dow) expressions are accepted when constructing from strings.

Like PeriodicTimer, only a single WaitForNextTickAsync call may be in flight at any time. Disposing the timer wakes any pending waiter with false.

Building

dotnet build

Testing

dotnet test

Packaging

The library automatically generates a NuGet package on Release builds:

dotnet build -c Release

The generated .nupkg and .snupkg (symbols) files can be found in bin/Release/.

Installation

dotnet add package LaquaiLib.Threading.CronTimer

Or from a local build:

dotnet nuget add source ./bin/Release --name local
dotnet add package LaquaiLib.Threading.CronTimer

Usage

Basic loop — fires every minute

using LaquaiLib.Threading.CronTimer;

using var timer = new CronTimer("* * * * *");

while (await timer.WaitForNextTickAsync())
{
    // executed once per minute
}

6-field expression — fires every second

using var timer = new CronTimer("* * * * * *");

Multiple expressions — fires at the earliest occurrence

// fires at :00 and :30 of every hour
using var timer = new CronTimer("0 * * * *", "30 * * * *");

Pre-parsed CronExpression objects

When constructing from CronExpression instances the expressions may use different formats (5-field and 6-field can be mixed freely):

using Cronos;

var everySecond = CronExpression.Parse("* * * * * *", CronFormat.IncludeSeconds);
var everyMinute = CronExpression.Parse("* * * * *",   CronFormat.Standard);

using var timer = new CronTimer(everySecond, everyMinute);

Custom time zone

var tz = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
using var timer = new CronTimer(tz, "0 9 * * 1-5"); // 09:00 Mon–Fri Eastern

Cancellation and disposal

WaitForNextTickAsync accepts a CancellationToken. The method returns false (without throwing) when the timer is disposed; it throws OperationCanceledException when the token is cancelled.

using var cts = new CancellationTokenSource();

using var timer = new CronTimer("* * * * *");

while (await timer.WaitForNextTickAsync(cts.Token))
{
    // ...
}

License

Unlicense