add WAIT_SECONDS

README.md

@@ -9,10 +9,16 @@ This function is supposed to be called by ASG lifecycle hook.
 ## Install
 
 ```console
-docker pull ghcr.io/kayac/asg-lifecycle-hook-ec2:v0.0.1
+docker pull ghcr.io/kayac/asg-lifecycle-hook-ec2:v0.0.3
 ```
 
-[Release packages]()
+[Release packages](https://github.com/kayac/asg-lifecycle-hook-ec2/releases)
+
+## Configuration
+
+All configuration parameters are defined in environment variables.
+
+- `WAIT_SECONDS`: Seconds until complete the lifecycle action after the instance deregistered from load balancers.
 
 ## LICENSE
 

main.go

@@ -6,7 +6,9 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"strconv"
 	"strings"
+	"time"
 	_ "time/tzdata"
 
 	"github.com/aws/aws-lambda-go/events"
@@ -82,6 +84,14 @@ func handler(ctx context.Context, event *events.AutoScalingEvent) error {
 	if err := drainInstance(sess, asgSvc, asgName, instanceID); err != nil {
 		return err
 	}
+	if s := os.Getenv("WAIT_SECONDS"); s != "" {
+		if n, err := strconv.ParseInt(s, 10, 64); err == nil {
+			log.Printf("[info] waiting %d seconds", n)
+			time.Sleep(time.Duration(n) * time.Second)
+		} else {
+			log.Printf("[error] invalid WAIT_SECONDS: %s, %s", s, err)
+		}
+	}
 	if err := complate(asgSvc, event); err != nil {
 		return err
 	}