lineprefix

io.Writer wrapper with line prefix and color customizations.

Usage

Static Prefix

prefix := lineprefix.Prefix("app |")
writer := lineprefix.New(prefix)

fmt.Fprintln(writer, "hello world")

output

app | hello world

Dynamic Prefix

now := func() string { return time.Now().UTC().Format("2006-01-02 15:04:05") }
prefix := lineprefix.PrefixFunc(now)
writer := lineprefix.New(prefix)

for i := 0; i<3; i++ {
    fmt.Fprintln(writer, "hello world")
    time.Sleep(time.Second)
}

output

2021-06-01 18:53:15 hello world
2021-06-01 18:53:16 hello world
2021-06-01 18:53:17 hello world

Color

Colors can be added with fatih/color.

Colored Prefix

A prefix with blue text on white background.

blue := color.New(color.FgBlue, color.BgWhite).SprintFunc()
prefix := lineprefix.Prefix(blue("app"))
writer := lineprefix.New(prefix)

fmt.Fprintln(writer, "this outputs blue on white prefix text")

Colored Output

A blue colored output.

blue := color.New(color.FgBlue)
option := lineprefix.Color(blue)
writer := lineprefix.New(option)

fmt.Fprintln(writer, "this outputs blue color text")

Example

The example file has an overview of the capabilities.

go run example/main.go

Screenshot

colored prefix and colored text from the example.

License

MIT