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ptweezy edited this page Jun 23, 2026 · 2 revisions

Running on Windows

yacron2 runs natively on Windows, alongside Linux and macOS. This page is the canonical reference for the handful of behaviours that differ on Windows: how to install it, where it looks for configuration, how a string command is fed to a shell, how to stop the daemon, how a job is terminated, and the two POSIX-only features that are reported (never silently dropped) on Windows. Everything not listed here behaves exactly as it does on POSIX, so the rest of this wiki applies unchanged.

All of the OS-specific behaviour is isolated in a single module (yacron2/platform.py); the scheduler, job runner, config loader, and entry point read the same on every platform.

Supported platforms and architectures

yacron2 supports Windows on two CPU architectures: amd64 (x64) and arm64 (ARM64). You can install it either as a normal Python package or as a self-contained executable.

Architecture pip / pipx Standalone binary
amd64 (x64) pip install yacron2 yacron2-windows-amd64.exe
arm64 (ARM64) pip install yacron2 yacron2-windows-arm64.exe

The full test suite runs on Windows (both x64 and ARM64) in CI on every commit, and every release builds both Windows binaries. See Contributing and Releasing for the build and release workflow.

Installation

There are two ways to install yacron2 on Windows.

pip / pipx

pip install yacron2 works on Windows just as it does on POSIX, installing the yacron2 console script into your environment. A supported Python (3.10 or newer) must be present. See Installation for the Python and dependency requirements that apply on every platform.

pip install yacron2
yacron2 --version

Standalone binary (no Python required)

Every release attaches self-contained executables — yacron2-windows-amd64.exe (x64) and yacron2-windows-arm64.exe (ARM64) — on the releases page. Python is not required on the target system; the interpreter is embedded in the executable. Download the asset for your architecture, then run it:

yacron2-windows-amd64.exe --version

The binaries are built natively on Windows runners (the ARM64 binary on a windows-11-arm runner). As on every platform, the standalone binary is a self-extracting executable; for the writable-and-executable temp-directory detail (which matters only under unusual locked-down filesystems) see Installation.

There is no Windows container image — the published Docker image is Linux-only. See Installation for the Linux image and its supported architectures.

Default configuration location

When -c/--config is omitted, the directory yacron2 looks in is platform-specific:

Platform Default -c path
POSIX /etc/yacron2.d
Windows %APPDATA%\yacron2 (e.g. C:\Users\<you>\AppData\Roaming\yacron2)

On Windows the default is %APPDATA%\yacron2, the Windows analogue of /etc/yacron2.d. If APPDATA is somehow unset (rare — for example a bare service account with no roaming profile), yacron2 falls back to the user profile directory (~, i.e. os.path.expanduser("~")) and uses <profile>\yacron2.

You can point -c anywhere — a single YAML file or a directory of *.yaml / *.yml files — exactly as on POSIX:

yacron2 -c C:\path\to\yacron2tab.yaml

"Configuration file not found" applies to this path

yacron2 has a special-case exit for a missing default config path: when the -c argument is left at the platform default and that path does not exist, yacron2 prints the following to stderr, prints the usage help, and exits 1:

yacron2 error: configuration file not found, please provide one with the --config option

This check keys off the platform default value, not the literal string /etc/yacron2.d. On Windows it therefore fires when -c resolves to %APPDATA%\yacron2 (whether you omit -c or pass that path explicitly) and the directory does not exist. For any other non-existent path you pass with -c, you instead get the generic configuration-error path (a logged Configuration error: ... and exit 1). See the Command-Line Reference for the full argument and exit-code reference, and Troubleshooting and FAQ for the problem/cause/fix entry.

Default shell and running commands

How a string command is handed to a shell is platform-specific. The shell field itself works on every OS; only its default differs:

Platform Default shell A string command runs as
POSIX /bin/sh ["/bin/sh", "-c", command]
Windows empty command through the native command processor %ComSpec% (cmd.exe)

On Windows the default shell is empty. An empty shell routes a string command through the native command processor — %ComSpec%, i.e. cmd.exe — via asyncio.create_subprocess_shell, the closest equivalent to the POSIX /bin/sh -c path. A bare string command therefore runs under cmd.exe by default:

jobs:
  - name: hello
    command: echo Hello from cmd.exe
    schedule: "*/5 * * * *"
    captureStdout: true

Using PowerShell or another interpreter

To run a command under PowerShell, or any interpreter other than cmd.exe, you have two options. Set shell: explicitly:

jobs:
  - name: powershell-shell
    command: Get-Date
    shell: powershell
    schedule: "*/5 * * * *"
    captureStdout: true

…or pass command as a list, which bypasses the shell entirely on every platform (the argv is taken verbatim — no word splitting, globbing, quoting, or variable expansion is performed):

jobs:
  - name: powershell-list
    command:
      - powershell
      - -Command
      - Get-Date
    schedule: "*/5 * * * *"
    captureStdout: true

For the full shell-vs.-list semantics — including how defaults.shell is inherited and how launch failures are handled — see Commands and Environment.

Graceful shutdown

To stop yacron2 on Windows, press Ctrl-C (or Ctrl-Break). As on POSIX, this is a graceful shutdown: yacron2 stops scheduling new runs and finishes the currently running jobs first, exactly as SIGTERM does on POSIX. It does not force-kill its own running jobs on shutdown.

Internally, POSIX wires SIGINT/SIGTERM onto the asyncio event loop. The Windows Proactor loop has no add_signal_handler, so on Windows yacron2 instead installs signal.signal handlers for SIGINT (Ctrl-C) and SIGBREAK (Ctrl-Break / console close) and runs a lightweight heartbeat timer so the interpreter observes the pending handler promptly even while the loop is blocked in I/O. The user-visible behaviour is identical to POSIX. For the shutdown sequence in detail, see Signal handling and graceful shutdown in the Command-Line Reference.

Job termination semantics

When yacron2 stops a job — because its executionTimeout expired, because of concurrencyPolicy: Replace, or because of a cancel request through the HTTP Control API — it calls proc.terminate(), waits up to killTimeout seconds, then escalates to proc.kill(). The meaning of those two calls differs by platform:

Platform terminate() kill() Escalation
POSIX SIGTERM (graceful, trappable) SIGKILL (forceful) Real — a child can trap SIGTERM to clean up before SIGKILL.
Windows TerminateProcess TerminateProcess Moot — both calls are the same immediate, ungraceful stop.

On Windows there are no POSIX signals: both terminate() and kill() map to TerminateProcess, an immediate, ungraceful stop. The child is not notified to clean up, so the terminate() → kill() escalation is effectively moot — killTimeout still bounds how long yacron2 waits between the two calls, but the outcome is the same hard kill either way. A job cannot trap a "please shut down" signal on Windows the way it can trap SIGTERM on POSIX.

For the full cancellation sequence, the -100 timeout return code, and how concurrencyPolicy: Replace cancels the outgoing instance, see Concurrency and Timeouts.

Features not supported on Windows

Two POSIX-specific features cannot work on Windows. Neither is silently dropped: each is reported clearly.

Per-job user / group switching

Windows has no setuid/setgid model, so a job cannot drop to another user or group. A job with user or group set raises a configuration error at config load, verbatim:

Job <name>: changing user/group is not supported on Windows

Remove the user/group fields from the job to run it on Windows. For the POSIX semantics of these fields (resolution rules, the root requirement, and the demotion ordering), see Commands and Environment.

unix:// web listeners

aiohttp's UnixSite needs create_unix_server, which the Windows Proactor event loop does not provide, so unix:// web listeners cannot be bound. Such a web.listen URL is skipped — not fatal — with a warning, verbatim:

Ignoring web listen url <url>: unix-socket listeners are not supported on this platform

Use an http:// listener instead; it (and the entire HTTP control API and Web Dashboard) behaves identically on Windows:

web:
  listen:
    - http://127.0.0.1:8080

Because web.socketMode only ever applies to unix:// sockets, it is irrelevant on Windows. See the HTTP Control API for the listener configuration and Web Dashboard for the browser UI.

Everything else behaves identically

Apart from the differences above, yacron2 behaves the same on Windows as on POSIX. The YAML crontab, schedules and timezones, environment variables and env files, output capturing, concurrency, failure detection and retries, reporting (mail / Sentry / shell), statsd metrics, the HTTP control API, and the web dashboard all work exactly as documented elsewhere in this wiki:

See Installation and the Command-Line Reference to get started, and Troubleshooting and FAQ if something does not behave as expected.

This wiki documents yacron2. See the README and the changelog.

yacron2 is a fork of gjcarneiro/yacron.

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