Setting variables are sometimes used as a method to retailer the app configuration values. As an alternative of holding delicate knowledge like passwords in a code repository, we are able to simply set them as setting variables that this system then reads whereas operating. In Golang’s os bundle, there are some capabilities that make it simple to set or unset setting variables, get or record setting variables, and clear setting variables.
Have a look at the instance to match how these capabilities work:
bundle predominant
import (
"fmt"
"log"
"os"
"strings"
)
const userKey = "GOSAMPLES_USER"
func predominant() {
// set setting variable
err := os.Setenv(userKey, "admin")
if err != nil {
log.Deadly(err)
}
// get setting variable
fmt.Printf("os.Getenv(): %s=%sn", userKey, os.Getenv(userKey))
// iterate over all setting variables and examine if our variable is ready
for _, envStr := vary os.Environ() {
if strings.HasPrefix(envStr, userKey) {
fmt.Printf("os.Environ(): %s setting variable is ready: %sn", userKey, envStr)
}
}
// lookup setting variable
val, isSet := os.LookupEnv(userKey)
fmt.Printf("os.LookupEnv(): %s variable is ready: %t, worth: %sn", userKey, isSet, val)
// unset setting variable
if err := os.Unsetenv(userKey); err != nil {
log.Deadly(err)
}
// lookup setting variable once more - now it shouldn't be set
val, isSet = os.LookupEnv(userKey)
fmt.Printf("os.Unsetenv(); %s variable is ready: %t, worth: %sn", userKey, isSet, val)
// clear setting variables
os.Clearenv()
fmt.Printf("os.Clearenv(): variety of setting variables: %dn", len(os.Environ()))
}Output:
os.Getenv(): GOSAMPLES_USER=admin
os.Environ(): GOSAMPLES_USER setting variable is ready: GOSAMPLES_USER=admin
os.LookupEnv(): GOSAMPLES_USER variable is ready: true, worth: admin
os.Unsetenv(); GOSAMPLES_USER variable is ready: false, worth:
os.Clearenv(): variety of setting variables: 0
