kubectl-socks5-proxy

#!/usr/bin/env bash
#
# A kubectl plugin that creates a local SOCKS5 proxy through which you can access to pods/services in a Kubernetes cluster
#

[[ -n $DEBUG ]] && set -x -e

MAX_POD_CREATION_TIME=10  # unit: second
DEFAULT_NAME=$(echo ${USER}-proxy|sed -e 's/[^[:alnum:]|-]//g'|tr '[:upper:]' '[:lower:]')
DEFAULT_PORT=1080
DEFAULT_PROXY_NAMESPACE=default
DEFAULT_PROXY_IMAGE=serjs/go-socks5-proxy

help(){
  echo "Usage: "
  echo "  kubectl socks5-proxy"
  echo ""
  options
}

options(){
  cat << EOF
Options:
  -n, --namespace <namespace>   Namespace to create SOCKS5 proxy server in
                                Default: ${DEFAULT_PROXY_NAMESPACE}

  -p, --port <local port>       Local port to be forwarded to the SOCKS5 proxy server (Pod)
                                A client connects to this port, then the connection is forwarded to the 
                                SOCKS5 proxy server, which is then forwareded to the destination server
                                Default: ${DEFAULT_PORT}

  -N, --name <pod name>         Name to give the pod in the cluster
                                Default: ${DEFAULT_NAME}

  -i, --image <socks5 image>    Set the image used as socks5 proxy server
                                Default: ${DEFAULT_PROXY_IMAGE}

  --skip-cleanup-proxy          Skip cearning up SOCKS5 proxy pod
                                Default: Cleaning up SOCKS5 proxy pod at the end

  -h, --help                    Show this message
EOF
}

cleanup_proxy(){
  local namespace="$1"
  echo "Clearning up SOCKS5 proxy server (Pod)..."
  kubectl delete pod ${podname} -n ${namespace}
}

run_proxy(){
  local namespace="$1"
  local port="$2"
  local image="$3"

  # Install an SOCKS5 proxy server if not yet installed
  r=$(kubectl get pod ${podname} -n ${namespace} 2>/dev/null | tail -1 | awk '{print $1}') # 
  if [ "${r}" != "${podname}" ];then
    echo "Creating SOCKS5 Proxy (Pod)..."
    cat <<EOF | kubectl apply -n ${namespace} -f -
apiVersion: v1
kind: Pod
metadata:
  name: ${podname}
  labels:
    env: test
spec:
  containers:
  - name: ${podname}
    image: ${image}
    ports:
    - containerPort: 1080
  nodeSelector:
    "kubernetes.io/os": linux
EOF

    # Wait until SOCKS5 proxy server gets ready
    c=1
    while [[ ${c} -le ${MAX_POD_CREATION_TIME} ]];
    do
      pod_status=$(kubectl get pod ${podname} -n ${namespace} 2>/dev/null | tail -1 | awk '{print $3}')
      if [ "${pod_status}" = "Running" ]; then
        break
      fi
      (( c++ ))
      sleep 1
    done
  fi

  echo "Starting a local SOCKS5 Proxy (localhost:${port})..."
  echo ""
  echo "The proxy Pod can be cleaned up with ^C (if not in background),"
  echo "or with a command \"kubectl delete pod ${podname} -n ${namespace}\""
  echo ""
  # Setup portforward
  kubectl port-forward -n ${namespace} ${podname} $port:1080 
}

plugin_main() {
  skip_cleanup_proxy=no
  while [ $# -gt 0 ] ; do
    nSkip=1
    case $1 in
      "-h" | "--help")
        help
        exit 0
      ;;
      "--skip-cleanup-proxy")
        skip_cleanup_proxy=yes
      ;;
      "-n" | "--namespace" )
        namespace=$2
        nSkip=2
      ;;
      "-p" | "--port" )
        port=$2
        nSkip=2
      ;;
      "-N" | "--name" )
        podname=$2
        nSkip=2
      ;;
      "-i" | "--image" )
        image=$2
        nSkip=2
      ;;
      *)
        help >&2
        exit 1
      ;;
    esac
    shift $nSkip
  done

  if [[ "$(type kubectl &>/dev/null; echo $?)" -eq 1 ]]; then
    echo "Error: missing kubectl command" >&2
    echo "Please install kubectl (https://kubernetes.io/docs/tasks/tools/install-kubectl/)" >&2
    exit 1
  fi

  if [ ! -n "${namespace}" ]; then
    namespace=${DEFAULT_PROXY_NAMESPACE}
  fi
  echo "using: namespace=${namespace}"

  if [ ! -n "${port}" ]; then
    port=${DEFAULT_PORT}
  fi
  echo "using: port=${port}"

  if [ ! -n "${podname}" ]; then
    podname=${DEFAULT_NAME}
  fi
  echo "using: name=${podname}"

  if [ ! -n "${image}" ]; then
    image=${DEFAULT_PROXY_IMAGE}
  fi
  echo "using: image=${image}"

  run_proxy "${namespace}" "${port}" "${image}"

  # Cleaning up SOCKS5 proxy server if needed
  if [ "${skip_cleanup_proxy}" = "no" ]; then
    cleanup_proxy "${namespace}"
  fi
}

plugin_main "$@"