#!/bin/bash
#
# Generated by Chef
#
# Back up directories/files into an S3 bucket

set -e

suffix=.backup_file_to_s3
if [ -f /tmp/*"$suffix" ] ; then
    ( >&2 echo "[ERROR] Another operation might still be in progress" )
    exit 200
fi
tmp_file=$( mktemp --suffix "$suffix" )

bucket=<%= @bucket %>
region=<%= @region %>
bak_dir=<%= @tmp_dir %>

aws_bin=<%= @aws_bin %>
tar_bin=<%= @tar_bin %>

pub_key_file=<%= @pub_key_file %>

# Create the tarball.
# Args:
#   $1 = full path to be backed up, e.g. '/var/src/mydir'
#   $2 = desired filename, sans '.tar.gz' extension, e.g. 'myfilename'
tar_dir() {
    bname=$( basename "$1" )
    dname=$( dirname "$1" )

    echo "$(date) : Creating tarball from ${1}"
    "$tar_bin" -C "${dname}" -czf "${bak_dir}/${2}.tar.gz" "$bname"
}

# Encrypt a tarball using OpenSSL and a given public key.
# The original file will be replaced by a new one with the same filename,
# suffixed with '.enc'.
#
# Given file should be located in $bak_dir.
# Args:
#   $1 = filename, sans '.tar.gz' extension, e.g. 'myfilename'
encrypt_tarball() {
    echo "$(date) : Encrypt file ${1}.tar.gz"
    openssl smime -encrypt -binary -text -aes256 -in "${bak_dir}/${1}.tar.gz" \
            -out "${bak_dir}/${1}.tar.gz.enc" -outform DER "${pub_key_file}"
    rm "${bak_dir}/${1}.tar.gz"
}

# Rotate the number suffixes of the current backups in S3
# Args:
#   $1 = filename, sans '.tar.gz' extension, e.g. 'myfilename'
#   $2 = max number of backup copies to store at a time
increment_backup_names() {
    bak_keyname=$1
    max_backups=$2

    # Backups will stored inside subdirectories (prefixes)
    # in S3, so only look at 'PRE' objects.
    baks=$( "$aws_bin" --output text --region "$region" \
            s3 ls "s3://${bucket}/" | grep '^\s*PRE' | \
            sed -e 's/^ *PRE //' -e 's/\/$//' | \
            grep "^${bak_keyname}" || echo "" )

    echo "$(date) : Backup rotation for ${bak_keyname}"
    start=$((max_backups - 1))

    for (( x=start ; x > 0 ; x-- )) ; do
        if echo "$baks" | grep "^${bak_keyname}\\.${x}\$" ; then
            newx=$((x + 1))
            if [[ $newx -lt $max_backups ]] ; then
                "$aws_bin" --region "$region" \
                    s3 mv --recursive "s3://${bucket}/${bak_keyname}.${x}" \
                          "s3://${bucket}/${bak_keyname}.${newx}"
            else
                "$aws_bin" --region "$region" \
                    s3 rm --recursive "s3://${bucket}/${bak_keyname}.${x}"
            fi
        fi
    done

    if echo "$baks" | grep "^${bak_keyname}\$" ; then
        "$aws_bin" --region "$region" \
            s3 mv --recursive "s3://${bucket}/${bak_keyname}" \
                  "s3://${bucket}/${bak_keyname}.1"
    fi
}

# Upload the tarball to the S3 bucket. It will be uploaded
# to this location: ${bucket}/basename/myfile.tar.gz.enc
#
# A timestamp file will also be uploaded to this location:
# ${bucket}/basename/YYYY-MM-DDThh:mm:ss.txt
# Args:
#   $1 = filename, sans '.tar.gz' extension, e.g. 'myfilename'
#   $2 = if file is encrypted or not (boolean)
upload_to_s3() {
    bak_keyname=$1
    if [ "$2" = true ] ; then
        fname="${1}.tar.gz.enc"
    else
        fname="${1}.tar.gz"
    fi

    echo "$(date) : Upload ${fname} to S3 bucket ${bucket}"

    stamp=$( date +"%FT%T" )
    echo "Uploaded: ${stamp}" > "${bak_dir}/${stamp}.txt"

    "$aws_bin" --region "$region" \
        s3 mv "${bak_dir}/${fname}" \
        "s3://${bucket}/${bak_keyname}/${fname}"
    "$aws_bin" --region "$region" \
        s3 mv "${bak_dir}/${stamp}.txt" \
        "s3://${bucket}/${bak_keyname}/${stamp}.txt"
}

if [[ ! -d "$bak_dir" ]] ; then
    mkdir -p "$bak_dir"
fi

<% @paths.each do |path| -%>
<%   bname  = path[:bak_filename] || ::File.basename(path[:path]) -%>
<%   is_enc = path.has_key?(:bak_encrypted) ? path[:bak_encrypted] : false -%>
if [[ -d <%= path[:path] %> || -f <%= path[:path] %> ]] ; then
    increment_backup_names <%= bname %> <%= path[:bak_maxcopies] || 30 %>
    tar_dir <%= path[:path] %> <%= bname %>
<%   if is_enc -%>
    encrypt_tarball <%= bname %>
<%   end -%>
    upload_to_s3 <%= bname %> <%= is_enc %>
else
    >&2 echo "$(date) [WARNING] Path <%= path[:path] %> does not exist"
fi

<% end -%>
rm "$tmp_file"
echo "$(date) : Done"