cachenv

README

cachenv

Versatile memoizing cache for program invocations, with a virtualenv-like interface.

Overview

cachenv is a lightweight tool that provides caching for your commands, scripts, and pipelines. In fact, any program that calls exec() can use cachenv.

It's like function memoization, but at the process boundary. This is useful in a variety of contexts, especially testing and rapid iteration.

The workflow mirrors that of virtualenv - you create an environment, activate it, and work within it.

Features

Comprehensive Caching	Captures stdout, stderr, and exit codes, providing a complete snapshot of a program's behavior given a particular input.
Selective Memoization	Supports precise configuration to selectively enable caching based on program name, arguments, and/or input patterns.
Streaming Mode	Supports caching at the line level, keyed by stdin.
File Awareness	Can optionally distinguish cache entries based on the contents of files provided as arguments (e.g., for grep foo bar.txt, refresh the cache when the content of bar.txt changes).
Pipeline Compatibility	Naturally integrates with command pipelines, allowing a mix of cached and live executions within complex command chains. Also includes optimizations which can effectively cache entire pipelines.
Diff Mode	Can show changes in a program's behavior against a cached snapshot.
Faithful Replication	Interleaves lines of stdout and stderr in the same order they were generated by the original program (when possible).
Cross-Environment Portability	Enables cache sharing and reuse across different machines and operating systems.

Use Cases

• Optimizing Development Workflows: Accelerates development and testing cycles for software that relies on external programs or data processing commands.
• Improving Script Performance: Boost the performance of scripts (or compiled programs) by caching the results of expensive program executions, making repeated invocations significantly faster.
• Efficient Resource Utilization: Reduces calls to metered APIs and conserves bandwidth by caching program interactions that would otherwise redundantly fetch the same data.
• Reliable Testing Environments: Ensures consistent and quick retrieval of program outputs for testing frameworks and automation, minimizaing external dependencies.