Project goutils

Simple and useful functions for go.

Package: goutils

go get github.com/m-szalik/goutils 

Converters

• BoolToStr(b bool, trueVal, falseVal string) string
  BoolToStr - return string for true or false bool value
• BoolTo[T interface{}](b bool, trueVal, falseVal T) T
  BoolTo - return T object for true or false bool value
• HexToInt(hex string) (int, error)
  HexToInt convert hex representation to int
• ParseBool(str string) (bool, error)
  ParseBool - return bool. True is one of "true", "1", "on", false is one of "false", "0", "off"
• ParseValue(str string) interface{}
  ParseValue - converts string to one of int64, flot64, string, bool, nil.
  If impossible to covert the same string is returned.
• AsFloat64(i interface{}) (float64, error)
  AsFloat64 - convert multiple types (float32,int,int32,int64,string,[]byte) to float64.
• RoundFloat(val float64, precision uint) float64
  RoundFloat round float64 number

Slices

• SliceIndexOf(slice []interface{}, e interface{}) int SliceIndexOf find an element in a slice.
  Returns index of the element in a slice or -1 if not found.
• SliceContains(slice []interface{}, e interface{}) bool SliceContains check if slice contains the element
• SliceRemove[T comparable](slice []T, e any) ([]T, int) SliceRemove remove the element from a slice. Returns []T = new slice, int number of removed elements.
• SliceMap[I interface{}, O interface{}](inputData []I, mapper func(I) O) []O Map slice to slice of different object.
  Example:

    sliceOfStrings := goutils.SliceMap[int, string]([]int{2, 7, -11}, func(i int) string { return fmt.Sprint(i) })

Other utils

• ExitOnError(err error, code int, message string, messageArgs ...interface{})
• Env(name string, def string) string
• EnvInt(name string, def int) int
• CloseQuietly(closer io.Closer)
• Root(x, n float64) float64 Root - this function calculate approximation of n-th root of a number.

TimeProvider

An abstraction for time.Now() that allows independent testing.

type TimeProvider interface {
	Now() time.Time
}

Create TimeProvider:

tpMock := goutils.NewMockTimeProvider()
tpSystem := goutils.SystemTimeProvider()

StopWatch

sw := goutils.NewStopWatch()
sw.Start()
// some task here
sw.Stop()
fmt.Printf("execution of a task took %s", sw)

Package: collector

go get github.com/m-szalik/goutils/collector 

Few implementation of collections including:

• NewRollingCollection - Collection that keeps last N added elements.
• NewSimpleCollection - Collection that keeps all elements, slice that grows when needed.
• NewTimedCollection - Collection that keeps elements for defined duration only.
• NewDataPointsCollector - Collection that can calculate Avg, Max or Min over a time window.
• NewStack - implementation of stack data structure.

Package: throttle

go get github.com/m-szalik/goutils/throttle 

Few implementation throttling.

Package: pubsub

go get github.com/m-szalik/goutils/pubsub 

Simple Publish-Subscribe implementation based on channels.
Implementation allows to have multiple subscribers as well as multiple publishers.

Example