#!/bin/bash

set -ex

# Snippet from: https://coreos.com/etcd/docs/latest/admin_guide.html
# Snapshot a running etcd cluster data.
# This command will rewrite some of the metadata contained in the backup
# (specifically, the node ID and cluster ID), which means that the node will
# lose its former identity. In order to recreate a cluster from the backup, you
# will need to start a new, single-node cluster. The metadata is rewritten to
# prevent the new node from inadvertently being joined onto an existing cluster.

ETCD_BACKUP_TARGET_DIR=$(action-get target)
ETCD_KEYS_VERSION=$(action-get keys-version)
#ETCD_DATA_DIR=/var/lib/etcd/default
UNIT_NAME=${JUJU_UNIT_NAME%%/*}
UNIT_NUM=${JUJU_UNIT_NAME#*/}
ETCD_DATA_DIR=/var/snap/etcd/current/$UNIT_NAME$UNIT_NUM.etcd/
if [ ! -d "$ETCD_DATA_DIR" ]; then
  ETCD_DATA_DIR=/var/snap/etcd/current/
fi

DATE_STAMP=$(date +%Y-%m-%d-%H.%M.%S)
ARCHIVE=etcd-snapshot-$DATE_STAMP.tar.gz

# Ensure the backupd target exists
mkdir -p $ETCD_BACKUP_TARGET_DIR/$JUJU_ACTION_UUID

if [ "${ETCD_KEYS_VERSION}" == "v2" ]; then
  # Dump the data currently in the cluster
  /snap/bin/etcd.etcdctl backup --data-dir $ETCD_DATA_DIR --backup-dir $ETCD_BACKUP_TARGET_DIR/$JUJU_ACTION_UUID
elif [ "${ETCD_KEYS_VERSION}" == "v3" ]; then
  mkdir -p $ETCD_BACKUP_TARGET_DIR/$JUJU_ACTION_UUID
  cp $ETCD_DATA_DIR/member/snap/db $ETCD_BACKUP_TARGET_DIR/$JUJU_ACTION_UUID
else
  action-fail "keys-version must be either v2 or v3"
  exit
fi

# Create the backup archive
cd $ETCD_BACKUP_TARGET_DIR/$JUJU_ACTION_UUID
tar cvfz ../$ARCHIVE .

# keep things tidy
cd ..
rm -rf $JUJU_ACTION_UUID

action-set snapshot.path="$ETCD_BACKUP_TARGET_DIR/$ARCHIVE"
action-set snapshot.size="$(du -h $ETCD_BACKUP_TARGET_DIR/$ARCHIVE | cut -d$'\t' -f1)"
action-set snapshot.sha256="$(sha256sum $ETCD_BACKUP_TARGET_DIR/$ARCHIVE | cut -d' ' -f1)"
action-set copy.cmd="juju scp $JUJU_UNIT_NAME:$ETCD_BACKUP_TARGET_DIR/$ARCHIVE ."
action-set snapshot.version="$(/snap/bin/etcd.etcdctl version)"