net-forward

#!/usr/bin/env bash
# author: AntiTree

function description() {
    echo -e "\nDescription:\n   This plugin allows you to forward to adjacent network services exposed within the cluster.  \
It can also help find services for you and help you forward to them.\n\n
    kubectl net_forward [-i DESTIP] [-p DESTPORT] [-l LISTENPORT] [-n NAMESPACE] \n
    \n - To choose a specific namespace to connect from run:\n\tkubectl net_forward -n YOURNAMESPACE
    \n - To choose an IP to connect to run:\n\tkubectl net_forward -i 10.24.0.1
    \n - To choose a port to connect to run:\n\tkubectl net_forward -p 80
    \n - Set IP, port, and local listening port: \n\tkubect net_forward -i 10.24.0.1 -p 443 -l 8888
    "
    exit 0
}

function _kube_get_ips() {
  # Get a list of pods
  # Lookup their internal IPs
  # Return list of pods and IPs exposed
  echo "on the roadmap"
}

function _deploy_nmap() {
  # Create an nmap pod
  # Prompt to confirm which subnets (1.g. 10.23.0.0/16)
  # Ping sweep the subnets
  # create a status bar
  # Collect the results
  # return a table
  echo "on the roadmap"
}

function _kube_list_pods() {
  # get list of pods that are accessible
  NS_ARG="--all-namespaces"
  [[ -n "$1" ]] && NS_ARG="-n ${1}"
  IFS=';' read -ra pods <<< "$(kubectl get pods $NS_ARG -o go-template='{{range .items}}{{.metadata.name}}:{{.metadata.namespace}}:{{.status.phase}}{{"\n"}}{{end}}' | sort -k 2 -k 1 -t: | tr '\n' ';')"

  local count=1
  lines=$(for i in ${pods[@]}; do
    IFS=":" read -ra TOKS <<< "${i}"
    printf "  $count) ${TOKS[0]}\t${TOKS[1]}\t${TOKS[2]}\n"
    ((count=count+1))
  done | column -t)
  count=$(echo "$lines" | wc -l)
  echo "$lines" >&2
  local sel=0
  while [[ $sel -lt 1 || $sel -gt $count ]]; do
    read -p "Select a Pod: " sel >&2
  done
  echo "${pods[(sel-1)]}"
}

function _kube_list_pod_containers() {
  echo "I'm in list containers"
  POD=$1
  NAMESPACE=$2
  IFS=';' read -ra items <<< "$(kubectl get pod ${POD} -n ${NAMESPACE} -o go-template='{{range .spec.containers}}{{.name}}{{"\n"}}{{end}}' | tr '\n' ';')"
  local count=1
  lines=$(for i in ${items[@]}; do
    printf "  $count) ${i}\n"
    ((count=count+1))
  done | column -t)
  count=$(echo "$lines" | wc -l)
  if [[ $count -gt 1 ]]; then
    printf "\nPod has multiple containers:\n" >&2
    echo "$lines" >&2
    local sel=0
    while [[ $sel -lt 1 || $sel -gt $count ]]; do
      read -p "Select a Container: " sel >&2
    done
  fi
  echo "${items[(sel-1)]}"
}

#SEL=$(_kube_list_pods)
#IFS=":" read -ra POD <<< "${SEL}"


while getopts "hn:i:p:l:" arg; do
    case $arg in
        n) # Add Namespace
            export NAMESPACE="${OPTARG}"
            ;;

        i) # Add IP
            export IP="${OPTARG}"
            ;;

        p) # Add port
            export PORT="${OPTARG}"
            ;;

        h) # Show help
            description
            exit 1
            ;;

        l) # Adjust listener
            export LISTENER="${OPTARG}"
            ;;
      esac
done
shift $((OPTIND-1))

# Configure IP address
if [ -z $IP ]; then
  read -p "Enter a Destination IP address: " IP >&2
fi

# Configure port
if [ -z $PORT ]; then
  read -p "Enter Destination service port: [80] " PORT >&2
  PORT=${PORT:-80}
fi
echo "Setting up connection to $IP:$PORT"

# Defining local listening port
if [ -z $LISTENER ]; then 
  export LISTENER=9999
fi

# Kubectl command to run
KUBECTL='kubectl'

# Set namespace to use
if [ -z ${NAMESPACE} ]; then
  NAMESPACECMD=""
else
  NAMESPACECMD="-n $NAMESPACE"
fi

# Random pod name
PODNAME="net-forward-socat-$(env LC_ALL=C tr -dc a-z0-9 </dev/urandom | head -c 6)"

# Deploy socat pod
kubectl ${NAMESPACECMD} run --restart=Never --image=alpine/socat ${PODNAME} -- -d -d tcp-listen:${LISTENER},fork,reuseaddr tcp-connect:${IP}:${PORT}
kubectl ${NAMESPACECMD} wait --for=condition=Ready pod/${PODNAME}

echo "Forwarding connection to $NAMESPACE ${IP}:${PORT}. Access service on your local machine at 127.0.0.1:${LISTENER}"

# Forward from the local system on the LISTENER port to the IP:PORT specified
kubectl ${NAMESPACECMD} port-forward pod/${PODNAME} ${LISTENER}

# Cleanup
kubectl ${NAMESPACECMD} delete pod/${PODNAME}