Copy of the staging script to allow gprd access

This is just a copy with find and replace. We'll need something like
this for the During Blackout QA.

bin/production-tunnel.sh

+#!/usr/bin/env bash
+
+set -euo pipefail
+IFS=$'\n\t'
+
+GITLAB_USER=${GITLAB_USER:-$USER}
+ETC_HOSTS=/etc/hosts
+IP="127.0.0.1"
+GITLAB_HOSTNAME=${GITLAB_HOSTNAME:-gitlab.com}
+BASTION_HOST=${BASTION_HOST:-lb-bastion.gprd.gitlab.com}
+TUNNEL_TARGET_HOST=${TUNNEL_TARGET_HOST:-fe-01-lb-gprd.c.gitlab-production.internal}
+
+function remove_host() {
+    if [[ -n "$(grep $GITLAB_HOSTNAME /etc/hosts)" ]]
+    then
+        echo "$GITLAB_HOSTNAME Found in your $ETC_HOSTS, Removing now...";
+        sudo sed -i".bak" "/$GITLAB_HOSTNAME/d" $ETC_HOSTS
+    else
+        echo "$GITLAB_HOSTNAME was not found in your $ETC_HOSTS";
+    fi
+}
+
+function add_host() {
+    HOSTS_LINE="$IP\t$GITLAB_HOSTNAME"
+    if [[ -n "$(grep $GITLAB_HOSTNAME /etc/hosts)" ]]
+    then
+      echo "$GITLAB_HOSTNAME already exists : $(grep $GITLAB_HOSTNAME $ETC_HOSTS)"
+    else
+      echo "Adding $GITLAB_HOSTNAME to your $ETC_HOSTS";
+      sudo -- sh -c -e "echo '$HOSTS_LINE' >> /etc/hosts";
+
+      if [[ -n "$(grep $GITLAB_HOSTNAME /etc/hosts)" ]]
+      then
+        echo "$GITLAB_HOSTNAME was added successfully";
+        grep $GITLAB_HOSTNAME /etc/hosts;
+      else
+        echo "Failed to Add $GITLAB_HOSTNAME, Try again!";
+      fi
+    fi
+}
+
+
+# Make sure ssh works before
+ssh ${GITLAB_USER}@${BASTION_HOST} date
+
+sudo echo sudo obtained
+
+echo "Logging into staging bastion as $GITLAB_USER"
+
+ssh -N -L 8443:${TUNNEL_TARGET_HOST}:443 -L 8822:${TUNNEL_TARGET_HOST}:22 ${GITLAB_USER}@${BASTION_HOST} &
+
+echo Running socat listeners
+
+sudo socat -d TCP4-LISTEN:443,fork TCP4-CONNECT:localhost:8443 &
+SOCAT_PID_HTTPS=$!
+echo "socat HTTPS PID $SOCAT_PID_HTTPS"
+
+sudo socat -d TCP4-LISTEN:22,fork TCP4-CONNECT:localhost:8822 &
+SOCAT_PID_SSH=$!
+echo "socat SSH PID $SOCAT_PID_SSH"
+
+function finish {
+  remove_host
+  echo killing ssh tunnels
+  kill %1
+  echo killing socat HTTPS
+  sudo kill $SOCAT_PID_HTTPS
+  echo killing socat SSH
+  sudo kill $SOCAT_PID_SSH
+}
+trap finish EXIT
+
+
+add_host
+
+echo "Now visit https://${GITLAB_HOSTNAME}"
+echo "Press any key to close the tunnel"
+read