cronrun

日本語版 README Specification

cronrun is a CLI tool to run commands in either:

• cron mode: cronrun "<CRONTAB_LINE>"
• loop mode: cronrun --loop <command> [args...]
• optional logging: add --log

It is a foreground process (not a daemon): schedules exist only while cronrun is running.

Install

pipx install cronrun

Quick Start

# cron mode: run every minute
cronrun "* * * * * echo hello"

# loop mode: run immediately after each completion
cronrun --loop /bin/echo hello

# loop mode with shell expression
cronrun --loop "date; sleep 2"

# with logs
cronrun --log "* * * * * echo hello"

Usage

cron mode

cronrun [--log] "<minute> <hour> <day-of-month> <month> <day-of-week> <command> [args...]"

• The first 5 fields are parsed as the cron expression
• The rest is treated as one command string and executed through shell (/bin/sh -c equivalent)
• No overlap protection: if the next schedule arrives while a previous run is still running, a new run starts

Examples:

cronrun "*/5 * * * * php worker.php"
cronrun "0 2 * * * ./backup.sh"
cronrun "* * * * * flock -n /tmp/worker.lock php worker.php"

loop mode

cronrun [--log] --loop <command> [args...]

• Repeats: run -> wait -> run again
• Restarts immediately after each completion
• Commands run through shell
• Single argument is treated as the shell command string directly
• Multiple arguments are composed into one command string, then executed

Examples:

cronrun --loop "date; sleep 2"
cronrun --loop echo hello
cronrun --loop flock -n /tmp/worker.lock php worker.php

Signal Handling

On SIGINT (Ctrl+C) or SIGTERM:

• Stop starting new runs
• Wait for currently running child processes
• Exit after they finish

If no child process is running, it exits immediately.

Logging (--log)

Enable runtime logs with --log.

• Logs are written to stderr
• Timestamps use local timezone (ISO 8601)
• cron mode logs:
  • cron.next (next scheduled run time)
  • run.start
  • run.done (duration and exit code)
• loop mode logs:
  • run.start
  • run.done (duration and exit code)
• On SIGINT / SIGTERM:
  • signal.received
  • shutdown.waiting (only when running jobs exist)
  • shutdown.complete

Timezone and DST

• Schedule evaluation uses OS local timezone
• No tool-specific timezone option is provided
• DST transitions follow local time behavior

Exit Codes

• 0: normal exit (--help, --version, or graceful stop by signal)
• 1: input or validation errors (invalid cron, missing command, invalid arguments)

Time Acceleration Test (faketime)

Use faketime without --exclude-monotonic.

# cron mode (x10 accelerated wall-clock)
faketime -f "+0 x10" uv run --no-sync cronrun --log "* * * * * date"

# loop mode
faketime -f "+0 x10" uv run --no-sync cronrun --log --loop "date; sleep 2"

Notes:

• uv run --no-sync avoids reinstall noise during repeated local tests.
• If you use --exclude-monotonic, waits may follow real-time and the behavior can differ.

Notes

• Error messages are emitted to stderr as error: <message>
• cronrun does not manage crontab files, persistent daemonization, job history, or logging