gistfile1.txt

#!/usr/bin/env bash
# runscript.sh
# Usage: ./runscript.sh <ip-address>

set -euo pipefail

IP_ADDRESS=${1:-}
if [[ -z $IP_ADDRESS ]]; then
  echo "Usage: $0 <ip-address>"
  exit 1
fi

# --- 1. fetch the ENI for this IP (first match only) ------------------------
eni=$(aws ec2 describe-network-interfaces \
  --filters "Name=private-ip-address,Values=$IP_ADDRESS" \
  --query 'NetworkInterfaces[0]' \
  --output json 2>/dev/null) || eni="null"

if [[ -z $eni || $eni == "null" ]]; then
  echo "IP $IP_ADDRESS → not found"
  exit 0
fi

# extract fields
interface_type=$(jq -r '.InterfaceType // ""' <<<"$eni")
description=$(jq -r '.Description // ""'    <<<"$eni")
attachment_instance_id=$(jq -r '.Attachment.InstanceId // ""' <<<"$eni")
# we’ll refer directly to .TagSet via jq where needed

# --- 2. classify by InterfaceType & Description ----------------------------

# 2.1 Lambda
if [[ $interface_type == "lambda" ]]; then
  # desc: "AWS Lambda VPC ENI-<FunctionName>-<UUID>"
  name_part=${description#AWS Lambda VPC ENI-}
  lambda_name=${name_part%%-*}
  echo "Lambda $lambda_name"
  exit 0
fi

# 2.2 NLB
if [[ $interface_type == "network_load_balancer" ]]; then
  # desc: "ELB net/<NLB-name>/<id>"
  name_part=${description#ELB net/}
  nlb_name=${name_part%%/*}
  echo "NLB $nlb_name"
  exit 0
fi

# 2.3 ALB
if [[ $description == ELB\ app/* ]]; then
  # desc: "ELB app/<ALB-name>/<id>"
  name_part=${description#ELB app/}
  alb_name=${name_part%%/*}
  echo "ALB $alb_name"
  exit 0
fi

# 2.4 ECS
ecs_arn=$(jq -r '.TagSet[]? | select(.Key=="aws:ecs:taskArn") | .Value' <<<"$eni")
if [[ -n $ecs_arn ]]; then
  echo "ECS $ecs_arn"
  exit 0
fi

# 2.5 EKS branch (trunk vs branch is distinguished by InterfaceType)
if [[ $interface_type == "branch" ]]; then
  echo "EKS branch"
  exit 0
fi

# 2.6 EKS trunk
eks_node_id=$(jq -r '.TagSet[]? | select(.Key=="node.k8s.amazonaws.com/instance_id") | .Value' <<<"$eni")
if [[ -n $eks_node_id ]]; then
  node_name=$(aws ec2 describe-instances \
    --instance-ids "$eks_node_id" \
    --query 'Reservations[0].Instances[0].Tags[?Key==`Name`].Value|[0]' \
    --output text 2>/dev/null || echo "")
  echo "EKS ${node_name:-$eks_node_id}"
  exit 0
fi

# 2.7 plain EC2
if [[ -n $attachment_instance_id ]]; then
  inst_name=$(aws ec2 describe-instances \
    --instance-ids "$attachment_instance_id" \
    --query 'Reservations[0].Instances[0].Tags[?Key==`Name`].Value|[0]' \
    --output text 2>/dev/null || echo "")
  echo "EC2 ${inst_name:-$attachment_instance_id}"
  exit 0
fi

# 2.8 anything else
echo "Other"
exit 0