Exec

A lightweight library for executing blocks at specified intervals. This library aims to solve the following:

• Reliably run blocks at specified intervals regardless of the runtime duration of the block.
• Keep it light (avoid timezones and dependencies)

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     exec:
       github: mgomes/exec
   

2. Run shards install

Usage

require "exec"

Specify the execution intervals for your code blocks:

Exec.every(1.second) do
  do_work
end

Exec.every(3.hours) do
  do_work
end

Caveats

• In the usage examples above, if the do_work method takes longer to execute than the specified interval, the next interval will be executed before the existing code block has completed. Therefore, multiple versions of do_work will be executing concurrently. If this is a concern for your code block, ensure you have enough margin built into the interval or that you've built in other safety measures to prevent corruption.

• You'll likely want to compile your applications with the -Dpreview_mt flag to take advantage of parallel execution. You can then run your binary with the CRYSTAL_WORKERS=N environment variable. Set N to the number of cores on your CPU.