keymon / cachesh

Wrapper to cache commands stderr/stdout

cachesh

This is a wrapper command to cache the output, stderr and exit code of any random command.

The purpose is speed up executions of scripts, bootstraps, common tasks, etc.

Usage

cachesh <command> [args]

Check cachesh.sh for environment variables

Features

This is still in progress. I want to implement all these features, but I'm not in a hurry.

Requirements:

• In bash: must be portable, not require dependencies
• Cross platform support: MacOSX, linux, cygwin?
• Fast and transparent

I want to implement the following features:

• Cache any command stdout/stderr/exit using arguments as key
• Customize TTL
• Allow execute more complex expressions.
  • e.g: command_x | sort | uniq -c
• Alternative keys and invalidations (customizable by options):
  • Use only the command path
  • environment variables
  • check if update is required with external command
• Implement as much as possible using built-in functions to increase performance
• List existing cached objects keys
• Option to force update
• Functions to invalidate cache
  • Using command, wildcards, etc.
  • Garbage collection: clean up old stuff
• Keep output order of the stdout/stderr
• Optionally report to the user when is cached or not cached version
• Integrate this with bash-it: Speed up bash-it commands.
• Find and include absolute command path when computing the key
• Support to run as a symbolic link. For example:

mv /usr/local/bin/slow_program /usr/local/bin/slow_program.cachesh ln -s /usr/local/bin/cachesh /usr/local/bin/slow_program

## Notes and Questions

 * Q: Is SHA256 enough?
 * A: [This stackoverflow answer](http://stackoverflow.com/questions/4014090/is-it-safe-to-ignore-the-possibility-of-sha-collisions-in-practice/4014407#4014407) by [Thomas Pornin](http://stackoverflow.com/users/254279/thomas-pornin) gives a great response to that :)


## References/Credits

 * I got the idea from here: http://stackoverflow.com/questions/11900239/can-i-cache-the-output-of-a-command-on-linux-from-cli