README
¶
envflag
enflag is a lightweight Go library to allow environment variables overriding with command-line flags.
Install
go get github.com/bfontaine/envflag
Example
This example is available in example/main.go:
package main
import (
"flag"
"fmt"
"os"
"github.com/bfontaine/envflag"
)
func main() {
envflag.AutoSetup()
flag.Parse()
fmt.Printf("The key is '%s'\n", os.Getenv("KEY"))
}
Once compiled, here is how to use it:
$ ./example -e KEY=42
The key is '42'
$ export KEY=43
$ ./example
The key is '43'
$ export KEY=43
$ ./example -e KEY=41
The key is '41'
$ ./example -e KEY=41 -e KEY=abcd
The key is 'abcd'
Documentation
¶
Overview ¶
Package envflag provides a way to override environment variables with flags
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
View Source
var ErrMalformedValue = errors.New("Malformed environment key/value pair, expected <key>=<value>")
ErrMalformedValue is returned by Value.Set if the given key/value pair is not valid.
Functions ¶
func AutoSetup ¶
func AutoSetup()
AutoSetup is a shortcut for Setup("e", "Override environment variables"). It must be called before flag.Parse().
func Setup ¶
func Setup(flagName, usage string)
Setup creates a flag that will be used to override environment variables. It must be called before flag.Parse(). The flag can occur multiple times in the command-line.
Example ¶
package main
import (
"flag"
"fmt"
"os"
"github.com/bfontaine/envflag"
)
func main() {
envflag.Setup("e", "Override env variables")
flag.Parse()
fmt.Printf("The key is '%s'\n", os.Getenv("KEY"))
// This example will print:
// - "foobar" if it’s called as ./example -e KEY=foobar regardless of the
// environment variable "KEY"
// - "abc123" if it’s called as ./example AND the environment variable
// "KEY" is set to "abc123"
// - an empty key if no -e flag is passed and the environment variable
// "KEY" is empty or doesn’t exist
}
Output:
Types ¶
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