#!/bin/bash
# Copyright 2016 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file or at
# https://developers.google.com/open-source/licenses/bsd

# The existing replicas all have this prefix:
REPLICA_PREFIX="replica"

# The new replicas made from the restored primary will have this prefix:
NEW_REPLICA_PREFIX="replica-1"

CLOUD_PROJECT="monorail-staging"

DRY_RUN=true

echo Restoring backups to primary for ${CLOUD_PROJECT}. Dry run: ${DRY_RUN}
echo This will delete all read replicas with the prefix "${REPLICA_PREFIX}"
echo and create a new set of replicas with the prefix "${NEW_REPLICA_PREFIX}"
echo
echo Checking for existing read replicas to delete:

EXISTING_REPLICAS=($(gcloud sql instances list --project=${CLOUD_PROJECT} | grep ${REPLICA_PREFIX}- | awk '{print $1}'))

if [ ${#EXISTING_REPLICAS[@]} -eq 0 ]; then
  echo No replicas found with prefix ${REPLICA_PREFIX}
  echo List instances to find the replica prefix by running:
  echo gcloud sql instances list --project=${CLOUD_PROJECT}
  exit 1
fi

echo Deleting ${#EXISTING_REPLICAS[@]} existing replicas found with the prefix ${REPLICA_PREFIX}

for r in "${EXISTING_REPLICAS[@]}"; do
  echo Deleting ${r}
  cmd="gcloud sql instances delete ${r} --project=${CLOUD_PROJECT}"
  echo ${cmd}
  if [ ${DRY_RUN} == false ]; then
    ${cmd}
  fi
done

echo Checking for available backups:

DUE_TIMES=($(gcloud sql backups list --instance primary --project=${CLOUD_PROJECT} | grep SUCCESSFUL | awk '{print $1}'))

for index in ${!DUE_TIMES[*]}; do
  echo "[${index}] ${DUE_TIMES[${index}]}"
done

echo "Choose one of the above due_time values."
echo "NOTE: selecting anything besides 0 will require you to manually"
echo "complete the rest of the restore process."
echo "Recover from date [0: ${DUE_TIMES[0]}]:"
read DUE_TIME_INDEX

DUE_TIME=${DUE_TIMES[${DUE_TIME_INDEX}]}

cmd="gcloud sql backups restore ${DUE_TIME} --project=${CLOUD_PROJECT} --restore-instance=primary"
echo ${cmd}
if [ ${DRY_RUN} == false ]; then
  ${cmd}
fi

if [ "${DUE_TIME_INDEX}" -ne "0" ]; then
  echo "You've restored an older-than-latest backup. Please contact speckle-oncall@"
  echo "to request an on-demand backup of the primary before attempting to restart replicas,"
  echo "which this script does not do automatically in this case."
  echo "run 'gcloud sql instances create' commands to create new replicas manually after"
  echo "you have confirmed with speckle-oncall@ the on-demand backup is complete."
  echo "Exiting"
  exit 0
fi

echo "Finding restore operation ID..."

RESTORE_OP_IDS=($(gcloud sql operations list --instance=primary --project=${CLOUD_PROJECT} | grep RESTORE_VOLUME | awk '{print $1}'))

# Assume the fist RESTORE_VOLUME is the operation we want; they're listed in reverse chronological order.
echo Waiting on restore operation ID: ${RESTORE_OP_IDS[0]}

if [ ${DRY_RUN} == false ]; then
  gcloud sql operations wait ${RESTORE_OP_IDS[0]} --project=${CLOUD_PROJECT}
fi

echo Restore is finished on primary. Now create the new set of read replicas with the new name prefix ${NEW_REPLICA_PREFIX}:

TIER=($(gcloud sql instances describe primary --project=${CLOUD_PROJECT} | grep tier | awk '{print $2}'))

for i in {00..09}; do
  cmd="gcloud sql instances create ${NEW_REPLICA_PREFIX}-${i} --master-instance-name=primary --project=${CLOUD_PROJECT} --tier=${TIER} --region=us-central1"
  echo ${cmd}
  if [ ${DRY_RUN} == false ]; then
    ${cmd}
  fi
done

echo If the replica creation steps above did not succeed due to authentication
echo errors, you may need to retry them manually.
echo
echo
echo Backup restore is nearly complete.  Check the instances page on developer console to see when
echo all of the replicas are "Runnable" status. Until then, you may encounter errors in issue search.
echo In the mean time:
echo - edit settings.py to change the db_replica_prefix variable to be "${NEW_REPLICA_PREFIX}-"
echo   Then either "make deploy_prod" or "make deploy_staging" for search to pick up the new prefix.
echo   Then set the newly deploy version for besearch and besearch2 on the dev console Versons page.
echo Follow-up:
echo - Submit the change.
echo - Delete old versions of besearch because they run up the GAE bill.