go

Go packages and commands

This repository contains a collection of useful go packages and cmds that I've built over the past few years.

Commands

• deptrace: a simple command line tool to find how a particular package is imported by another. For example, the following will find the series of imports that lead grail-tidy to depend on testing. I've found it be much more useful than the various graphical tools for visualizing dependencies that don't seem to work that well. It's written to be parallized but I haven't needed to do so yet.

  deptrace --path grail.com/cmd/grail-tidy --src = $HOME/go/src/grail.com testing

pulsemon - pulse counting for a water meter

• pulsemon implements a simple water meter monitor using the piface board and a water meter with a reed switch built in. It supports alerting, logging of timestamps and is easily dockerized. It's also a decent example of how simple it is to use go concurrency for monitoring applications and avoids the complexity of interrupts and callbacks (which is handy since interrupts are not currently implemented for the piface board!).

Packages

• cmap: a simple concurrent mapper.

	sleeper := func(v interface{}) interface{} {
		n := v.(int)
		time.Sleep(time.Millisecond * 200)
		return -n
	}
	input := make(cmap.Vector, 1000)
	for i := range input {
		input[i] = i
	}
	then := time.Now()
	output := cmap.Map(input, sleeper, 100)
	taken := time.Now().Sub(then)
	if taken < 10*time.Second {
		fmt.Printf("nice and fast!\n")
	}
	fmt.Printf("len: %v\n", len(output))
	// Output: nice and fast!
	// len: 1000