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utils.go
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/
utils.go
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package testing
import (
"crypto/rand"
"fmt"
"io"
"log"
"net"
"strconv"
"time"
eventingv1alpha1 "github.com/kyma-project/kyma/components/eventing-controller/api/v1alpha1"
)
// binary cloudevent headers.
const (
CeIDHeader = "ce-id"
CeTypeHeader = "ce-type"
CeSourceHeader = "ce-source"
CeSpecVersionHeader = "ce-specversion"
)
type SubscriptionOpt func(*eventingv1alpha1.Subscription)
// GeneratePortOrDie generates a random 5 digit port or fail.
func GeneratePortOrDie() int {
tick := time.NewTicker(500 * time.Millisecond) //nolint:gomnd //the tickerinterval is only required here
defer tick.Stop()
timeout := time.NewTimer(time.Minute)
defer timeout.Stop()
for {
select {
case <-tick.C:
{
port, err := generatePort()
if err != nil {
break
}
if !isPortAvailable(port) {
break
}
return port
}
case <-timeout.C:
{
log.Fatal("Failed to generate port")
}
}
}
}
func generatePort() (int, error) {
table := [...]byte{'1', '2', '3', '4', '5', '6', '7', '8', '9'}
max := 4
// Add 4 as prefix to make it 5 digits but less than 65535
add4AsPrefix := "4"
b := make([]byte, max)
n, err := io.ReadAtLeast(rand.Reader, b, max)
if n != max {
return 0, err
}
if err != nil {
return 0, err
}
for i := 0; i < len(b); i++ {
b[i] = table[int(b[i])%len(table)]
}
num, err := strconv.Atoi(fmt.Sprintf("%s%s", add4AsPrefix, string(b)))
if err != nil {
return 0, err
}
return num, nil
}
// isPortAvailable returns true if the port is available for use, otherwise returns false.
func isPortAvailable(port int) bool {
address := fmt.Sprintf("localhost:%d", port)
listener, err := net.Listen("tcp", address)
if err != nil {
return false
}
if err := listener.Close(); err != nil {
return false
}
return true
}