build-socks-proxy

#!/usr/bin/env bash -e

instance_name="throw-away-$(date +%s)"
region=us-west1-b
ssh_key_dir="$(mktemp -d)"

cleanup() {
  echo "removing temp dir: $ssh_key_dir"
  rm -rf "$ssh_key_dir"

  echo "killing instance"
  gcloud compute instances delete --zone us-west1-b --quiet $instance_name
}
trap cleanup EXIT

echo "generating ssh key pair in: $ssh_key_dir"
ssh-keygen -t rsa -b 4096 -C '' -N '' -f "$ssh_key_dir/id_rsa" &>/dev/null
pub_key="$(< "$ssh_key_dir/id_rsa.pub")"

echo "creating instance: $instance_name"
gcloud compute instances create $instance_name \
  --zone $region \
  --machine-type f1-micro \
  --metadata "ssh-keys=foobar:$pub_key" \
  --maintenance-policy TERMINATE \
  --image debian-8-jessie-v20170124 \
  --image-project debian-cloud \
  --boot-disk-size 10

echo "discovering instance IP address"
ip_address="$(\
  gcloud compute instances describe $instance_name \
    --zone $region \
    --format json \
      | jq -r .networkInterfaces[].accessConfigs[].natIP \
)"

echo "creating SOCKS5 tunnel from localhost:5555 => $ip_address"
ssh -D 5555 -C -q -N \
  -i "$ssh_key_dir/id_rsa" \
  -o StrictHostKeyChecking=no \
    foobar@$ip_address