Workgroup

A small utility to manage the lifetime of a set of related goroutines.

Installation

$ go get -v github.com/ksdfg/workgroup/v2

Functions

Run

func Run(fns []func () interface{}, maxParallelGoroutines int) interface{}

Run will execute all functions in the slice passed to it in individual goroutines.
Goroutines are created in batches, never exceeding max parallel goroutines value passed as input.
Run blocks until all the goroutines spawned have ended execution.
The first function to return a non-nil value will trigger the end of execution of all other goroutines spawned.
The return value from the first function will be returned to the caller of Run.
If all none of the functions return a non-nil value, all the spawned goroutines will naturally end execution and Run will return nil.

RunTemplate

func RunTemplate(n int, template func (int) interface{}, maxParallelGoroutines int) interface{}

RunTemplate will execute a given template function n no. of times in individual goroutines.
Goroutines are created in batches, never exceeding max parallel goroutines value passed as input.
RunTemplate blocks until all the goroutines spawned have ended execution.
Each goroutine will pass an index to the template function which it can use to execute accordingly.
The first function to return a non-nil value will trigger the end of execution of all other goroutines spawned.
The return value from the first function will be returned to the caller of RunTemplate.
If all none of the functions return a non-nil value, all the spawned goroutines will naturally end execution and RunTemplate will return nil.

Examples

Run

package main

import (
	"fmt"
	"strings"

	"github.com/ksdfg/workgroup/v2"
)

// Search for substrings in parallel
func main() {
	// Declare phrase and keywords to search in phrase
	phrase := "A small utility to manage the lifetime of a set of related goroutines."
	keywords := []string{"function", "variable", "slice", "goroutine", "package"}

	// Create slice of functions
	// Each function checks if a keyword is a substring present in the phrase
	// Return the keyword if it is found
	// Return nil if it is not found
	var fns []func() interface{}
	for _, keyword := range keywords {
		kw := keyword
		fns = append(
			fns,
			func() interface{} {
				var k interface{}
				if strings.Contains(phrase, kw) {
					k = kw
				}
				return k
			},
		)
	}

	// Call Run to search for keywords in parallel, with a maximum of 3 goroutines running at a time
	output := workgroup.Run(fns, 3)
	fmt.Println(output, "found")
}

RunTemplate

package main

import (
	"fmt"
	"strings"
	
	"github.com/ksdfg/workgroup/v2"
)

// Search for substrings in parallel
func main() {
	// Declare phrase and keywords to search in phrase
	phrase := "A small utility to manage the lifetime of a set of related goroutines."
	keywords := []string{"function", "variable", "slice", "goroutine", "package"}

	// Call RunTemplate to search for keywords in parallel, with a maximum of 3 goroutines running at a time
	// Pass number of keywords as n
	// In the template function, check if the ith keyword is a substring in the phrase
	// Return the keyword if it is found
	// Return nil if it is not found
	output := workgroup.RunTemplate(
		len(keywords),
		func(index int) interface{} {
			var k interface{}
			if strings.Contains(phrase, keywords[index]) {
				k = keywords[index]
			}
			return k
		},
		3,
	)
	fmt.Println(output, "found")
}

Credits

Built as a replacement with revamped internal working and extended functionality for heptio/workgroup

because that became an internal library of contour, and most of the other libraries I found were nowhere as simple as this, leaving me to make an alternative myself (〒︿〒)