#!/usr/bin/env bash
#
# This script is designed to be run inside the container
#

# fail hard and fast even on pipelines
set -eo pipefail

# set debug based on envvar
[[ $DEBUG ]] && set -x

# configure etcd
export ETCD_PORT="${ETCD_PORT:-4001}"
export ETCD="$HOST:$ETCD_PORT"
export ETCD_PATH="${ETCD_PATH:-/deis/database}"
export ETCD_TTL="${ETCD_TTL:-20}"

export BUCKET_NAME=${BUCKET_NAME:-db_wal}

# wait for etcd to be available
until etcdctl --no-sync -C "$ETCD" ls >/dev/null 2>&1; do
  echo "database: waiting for etcd at $ETCD..."
  sleep $((ETCD_TTL/2))  # sleep for half the TTL
done

# wait until etcd has discarded potentially stale values
sleep $((ETCD_TTL+1))

function etcd_set_default {
  set +e
  ERROR="$(etcdctl --no-sync -C "$ETCD" mk "$ETCD_PATH/$1" "$2" 2>&1 >/dev/null)"

  if [[ $? -ne 0 ]] && echo "$ERROR" | grep -iqve "key already exists"; then
    echo "etcd_set_default: an etcd error occurred ($ERROR)"
    echo "aborting..."
    exit 1
  fi
  set -e
}

etcd_set_default engine postgresql_psycopg2
etcd_set_default adminUser "${PG_ADMIN_USER:-postgres}"
etcd_set_default adminPass "${PG_ADMIN_PASS:-changeme123}"
etcd_set_default user "${PG_USER_NAME:-deis}"
etcd_set_default password "${PG_USER_PASS:-changeme123}"
etcd_set_default name "${PG_USER_DB:-deis}"
etcd_set_default bucketName "${BUCKET_NAME}"

# stub out the confd reload script before it gets templated
echo '#!/bin/sh' > /usr/local/bin/reload
chmod 0755 /usr/local/bin/reload

# wait for confd to run once and install initial templates
until confd -onetime -node "$ETCD" -confdir /app --log-level error; do
  echo "database: waiting for confd to write initial templates..."
  sleep $((ETCD_TTL/2))  # sleep for half the TTL
done

PG_DATA_DIR=/var/lib/postgresql/9.3/main

# initialize database if one doesn't already exist
# for example, in the case of a data container
if [[ ! -d $PG_DATA_DIR ]]; then
  chown -R postgres:postgres /var/lib/postgresql
  sudo -u postgres /usr/bin/initdb -D $PG_DATA_DIR
fi

# ensure WAL log bucket exists
envdir /etc/wal-e.d/env /app/bin/create_bucket "${BUCKET_NAME}"
INIT_ID=$(etcdctl -C "$ETCD" get "$ETCD_PATH/initId" 2> /dev/null || echo none)
echo "database: expecting initialization id: $INIT_ID"

initial_backup=0
if [[ "$(cat $PG_DATA_DIR/initialized 2> /dev/null)" != "$INIT_ID" ]]; then
  echo "database: no existing database found or it is outdated."
  # check if there are any backups -- if so, let's restore
  # we could probably do better than just testing number of lines -- one line is just a heading, meaning no backups
  if [[ $(envdir /etc/wal-e.d/env wal-e --terse backup-list | wc -l) -gt "1" ]]; then
    echo "database: restoring from backup..."
    rm -rf $PG_DATA_DIR
    sudo -u postgres envdir /etc/wal-e.d/env wal-e backup-fetch $PG_DATA_DIR LATEST
    chown -R postgres:postgres $PG_DATA_DIR
    chmod 0700 $PG_DATA_DIR
    echo "restore_command = 'envdir /etc/wal-e.d/env wal-e wal-fetch \"%f\" \"%p\"'" | sudo -u postgres tee $PG_DATA_DIR/recovery.conf >/dev/null
  else
    echo "database: no backups found. Initializing a new database..."
    initial_backup=1
  fi
  # either way, we mark the database as initialized
  INIT_ID=$(cat /proc/sys/kernel/random/uuid)
  echo "$INIT_ID" > $PG_DATA_DIR/initialized
  etcdctl --no-sync -C "$ETCD" set "$ETCD_PATH/initId" "$INIT_ID" >/dev/null
else
  echo "database: existing data directory found. Starting postgres..."
fi

# Explicitly correct permissions on this file.  This compensates for the fact
# it may have been initially written by root above, but more importantly, if
# it's already owned by root, this will correct the permissions during upgrade.
chown postgres:postgres /var/lib/postgresql/9.3/main/initialized

# run the service in the background
sudo -i -u postgres /usr/bin/postgres \
                    -c config-file="${PG_CONFIG:-/etc/postgresql/main/postgresql.conf}" \
                    -c listen-addresses="${PG_LISTEN:-*}" &

SERVICE_PID=$!

# smart shutdown on SIGINT and SIGTERM
function on_exit() {
    kill -TERM $SERVICE_PID
    wait $SERVICE_PID 2>/dev/null
    exit 0
}
trap on_exit INT TERM

# spawn confd in the background to update services based on etcd changes
confd -node "$ETCD" -confdir /app --log-level error --interval 5 &

# wait for the service to become available
until sudo -u postgres psql -l -t >/dev/null 2>&1; do sleep 1; done

# perform a one-time reload to populate database entries
/usr/local/bin/reload

if [[ "${initial_backup}" == "1" ]] ; then
  echo "database: performing an initial backup..."
  # perform an initial backup
  sudo -u postgres envdir /etc/wal-e.d/env wal-e backup-push $PG_DATA_DIR
fi

sudo -Eu postgres /app/bin/backup &

echo "database: postgres is running..."

# publish the service to etcd using the injected HOST and EXTERNAL_PORT
if [[ ! -z $EXTERNAL_PORT ]]; then
  # configure service discovery
  PORT=${PORT:-5432}
  PROTO=${PROTO:-tcp}

  set +e

  # wait for the service to become available on PORT
  until sudo -u postgres psql -l -t >/dev/null 2>&1; do sleep 1; done

  # while the port is listening, publish to etcd
  while [[ ! -z $(netstat -lnt | awk "\$6 == \"LISTEN\" && \$4 ~ \".$PORT\" && \$1 ~ \"$PROTO.?\"") ]] ; do
    etcdctl --no-sync -C "$ETCD" set "$ETCD_PATH/host" "$HOST" --ttl "$ETCD_TTL" >/dev/null
    etcdctl --no-sync -C "$ETCD" set "$ETCD_PATH/port" "$EXTERNAL_PORT" --ttl "$ETCD_TTL" >/dev/null
    sleep $((ETCD_TTL/2)) # sleep for half the TTL
  done

  # if the loop quits, something went wrong
  exit 1

fi

wait