#!/bin/bash

# alfplayer
# 2014-06-12

# Bash script to mirror only some repositories of Parabola.

script_filename="$(basename "$0")"

# Default configuration values.
# They can be overridden by setting the variables in the calling environment.
# 1 to set, 0 to unset
: ${project:=parabola}
: ${server:=rsync://repo.parabola.nu:875/repos}      # remote rsync directory
#: ${server:=rsync://alfplayer.com/repos/parabola}
#: ${server:=rsync://parabolagnulinux.mirrors.linux.ro/parabolagnulinux}
: ${base_dir:=/srv/http}
: ${local_dir:=${base_dir}/${project}}         # symlink to the last snapshot
: ${repos:=core extra community multilib libre kernels libre-multilib libre-multilib-testing libre-testing nonprism nonprism-testing java cross pcr}
  # mips64el is also excluded in some rsync invocations in this script
: ${max_delete:=10000}    # maximum amount of files to delete in the local directory
[[ ! ${bw_limit} ]] && \
    : ${bw_limit:=1300}   # KB/s
: ${options:=-rltvH --no-p --no-g --max-delete=$max_delete --exclude=.* --bwlimit=${bw_limit} --no-motd --chmod=Dug=srwx,Fug=rw}
: ${oldest_version:=100}        # delete versions older than this version
: ${link_dest[0]:=${base_dir}/archlinux}
#: ${link_dest[1]:=${base_dir}/parabola.secondary_mirror.tmp}
  # link-dest does not support any network URI like rsync://...
: ${date_exclude:=2014.06.19}    # disable running this script this date (see next line)
: ${force_run:=0}            # set to 1 to force running on excluded date
#: ${terminal:=1}             # outputs to stdout using rsync --progress
: ${alternative_mirror:=0}     # use alternative mirror; forces no_snapshot_delete and disables snapshot_symlink_update; synchronized files end up in ${local_dir}.tmp
: ${no_snapshot_delete:=0}     # disable deletion of oldest snapshots; alternative_mirror enables it forcefully
: ${leave_tmp:=0}              # leave updated tree in {project}.tmp instead of creating a dated snapshot directory
: ${snapshot_symlink_update:=1}         # update symlink to last snapshot
			       # does nothing if leave_tmp is enabled
: ${TZ:=UTC}              # set timezone to UTC
: ${db_and_symlinks_update:=1}         # update DB files and package symlinks
			  # disabling this uses existing file /tmp/parabola-mirror which can be left over the last invocation of parabola-mirror-repos with this option set
: ${pools_update:=1}      # update files in package pools
: ${no_file_delete:=1}     # do not delete files
: ${link_dest_snapshot_count=3}  # number of snapshots that are passed as --link-dest to rsync
[[ ! {path_list} ]] && \
    : ${path_list:=docs sources mirrorlist.txt lastupdate}    # list of extra paths to synchronize

export TZ

if [[ ${alternative_mirror} == 1 ]] ; then
    no_snapshot_delete=1
    leave_tmp=1
    #server="rsync://repo.parabola.nu:875/repos"
    server="rsync://parabolagnulinux.mirrors.linux.ro/parabolagnulinux"
    local_dir="${base_dir}/${project}.secondary_mirror"
    #link_dest=("${base_dir}/archlinux" "${base_dir}/parabola.tmp")
    link_dest+=("${base_dir}/${project}.tmp")
    for dir in "$local_dir" "$local_dir".tmp ${local_dir}.tmp/pool ; do
        if [[ ! -d "$dir" ]] ; then
            mkdir -pv "$dir"
            chmod -v 2770 "$dir"
        fi
    done
else
    #link_dest+=("${base_dir}/${project}.tmp")
    link_dest+=("${base_dir}/${project}.secondary_mirror")
fi


remote_pool_files="/tmp/${project}-remote-files"
local_pool_files="/tmp/${project}-local-files"
pool_files_to_delete="/tmp/${project}-to-delete-files"

# Lock with flock (provided by util-linux)
lockfile="/var/lock/${script_filename}"
lockfd=99

_lock()             { flock -$1 $lockfd; }

_no_more_locking()  {
    set +e

    # Save exit status
    es=$?

    if [[ -e ${local_dir}.tmp ]] ; then
	echo "=> WARNING: Temporary directory ${local_dir}.tmp remains in file system"
    fi

    if [[ $es != 0 ]] ; then
        echo "=> ERROR: Unsuccessful script termination. Exit status: $es"
    fi

    _lock u
    _lock xn && \
	rm -f $lockfile
}

_prepare_locking()  { eval "exec $lockfd>\"$lockfile\""; trap _no_more_locking EXIT; }

_prepare_locking

# Lock now. The lock is disabled automatically when the script exits (with any error code)
if ! _lock xn ; then
    echo "=> ERROR: Could not obtain lock. Exiting." >&2
    exit 1
fi

# Set non-configurable variables
date="$(date +%Y.%m.%d)"
current="${local_dir}-${date}"
current_component="${current##*/}"
for (( link_dest_count=1 ; link_dest_count <= ${link_dest_snapshot_count} ; link_dest_count++ )) ; do
	date_count="$(date -d @$(( $(date +"%s") - ${link_dest_count} * 86400)) +"%Y.%m.%d")"
	link_dest+=("${base_dir}/${project}-${date_count}")
done
current_exists=0
tmp_exists=0
local_useful=0
date_exact=""
first_run=0
if [[ ${bw_limit} ]] ; then
    options+=" --bwlimit=${bw_limit}"
fi
path_list_array=(${path_list})
repos_array=(${repos})

error() {
	echo "$@" >&2
	exit 1
}

if [[ ${date_exclude} && ${force_run} != 1 ]] ; then
    if [[ $date == ${date_exclude} ]] ; then
	echo "Manually disabled: ${date}. Exiting."
	exit 0
    fi
fi

# Parse options.
# -t or --terminal enables rsync option --progress
if [[ $# == 1 ]] ; then
  if [[ $1 == -t || $1 == --terminal ]] ; then
    terminal=1
  elif [[ $1 == -h ]] ; then
    echo "Available options: -h, -t (rsync --progress)"
  else
    echo "=> Wrong argument: $1"
  fi
elif [[ $# -gt 1 ]] ; then
  echo "=> ${script_filename} has a wrong number of arguments"
fi

if [[ $terminal == 1 ]] ; then
    options+=" --progress"
fi

# Create --link-dest option strings
for i in ${!link_dest[@]}; do
    if [[ -d ${link_dest[$i]} ]] ; then
        link_dest_option[i]="${link_dest[@]/#/--link-dest=}"
    else
        echo "=> WARNING: Argument to rsync option --link-dest is not an existing directory: ${link_dest[$i]}"
    fi
done

# Test if ${current} exists
if [[ -e ${current} ]] ; then
  current_exists=1
fi

# Test if ${local_dir}.tmp exists
if [[ -e ${local_dir}.tmp ]] ; then
  tmp_exists=1
fi

# Test if ${local_dir} is an existing symlink pointing to an existing directory
if [[ -h ${local_dir} ]] ; then
  last_path="$(readlink -f "${local_dir}")"
  if [[ -d ${last_path} ]] ; then
    last="${last_path##*/}"
    local_useful=1
  else
    error "=> ERROR: ${local_dir} is a symlink which does not point to an existing directory."
  fi
else
  if [[ -e ${local_dir} ]] || stat -t ${local_dir}-* >/dev/null 2>&1 ; then
    error "=> ERROR: ${local_dir} exists but is not a symlink, or a file (or directory) ${local_dir}-* was found. Fix this before running ${script_filename} again."
  else
    echo "=> WARNING: ${local_dir} does not exist or is not a symlink, and no snapshot directories were found, so it is assumed this is the first time ${script_filename} is run using \"${base_dir}\" as the base directory."
    first_run=1
  fi
fi

# Check the current tree and issue warnings and errors based on the current tree state
# Also, it sets up the temporary directory
if [[ ${current_exists} == 1 ]] ; then
  echo "=> WARNING: ${current} already exists. It will be preserved."
  no_snapshot_delete=1
  if [[ ${local_useful} == 1 ]] ; then
    if [[ ${tmp_exists} == 0 ]] ; then
      echo "=> WARNING: ${local_dir}.tmp does not exist."
      cp -al "${current}" "${local_dir}".tmp
    fi
    date_exact="$(date +%Y.%m.%d-%T)"
    echo "=> WARNING: Snapshot ${local_dir}-${date_exact} will be created because ${current} already exists"
  else
    echo "=> WARNING: ${local_dir} does not exist. It will be created."
    if [[ ${tmp_exists} == 0 ]] ; then
      echo "=> WARNING: As ${local_dir}.tmp does not exist, data transfer will start from ${current}"
      cp -al "${current}" "${local_dir}".tmp
    else
      echo "=> WARNING: Data transfer will start from ${local_dir}.tmp"
    fi
  fi
elif [[ ${local_useful} == 0 ]] ; then
  if [[ ${tmp_exists} == 1 ]] ; then
    echo "=> ${local_dir} is not useful but ${local_dir}.tmp exists. Resuming from ${local_dir}.tmp"
    echo "=> WARNING: Symlink ${local_dir} does not exist. It will be created."
  else
    if [[  ${first_run} == 0 ]] ; then
      error "=> ERROR: ${local_dir}.tmp does not exist and ${local_dir} is not useful. Exiting."
    else
      mkdir "${local_dir}".tmp
    fi
  fi
else
  if [[ ${tmp_exists} == 1 ]] ; then
    echo "=> ${local_dir}.tmp already exists. Symlink \"${project}\" currently points to ${last_path}."
  else
    cp -al "${last_path}" "${local_dir}".tmp
  fi
fi

echo
echo "=> Creating snapshot for date ${date}"

# Change to the temporary directory
cd "${local_dir}".tmp

if [[ ${db_and_symlinks_update} == 1 ]] ; then

  # Delete temporary files that may be left over by a previous invocation of parabola-mirror-repos
  rm -f "$remote_pool_files" "$local_pool_files" "$pool_files_to_delete" || true
 
  remote_repo_dirs="${repos_array[@]/#/${server}/}"
  remote_repo_dirs="${remote_repo_dirs[@]/%//os}"

  echo "=> Getting pool path list"
  # Fetch symlinks from the server, extract symlink destinations and save them to the file $remote_pool_files
  rsync -lrv --out-format="%L" --dry-run --exclude 'mips64el' --exclude '*mips64el.pkg.tar.*' ${remote_repo_dirs[@]} "/tmp/${script_filename}.unexistent_filename" \
    | grep -- "->" \
    | grep "pool.*[^/]$" \
    | sed -e "s#.*\(pool/.*/.*\)#\1#" \
  >> "$remote_pool_files" || error "  => ERROR: Failed with error code: $?"
  
  if [[ ${first_run} == 0 ]] ; then
    echo "=> Getting local pool package file list"
    # Build a list of local packages
    find pool -mindepth 2 >> "$local_pool_files"

    echo "=> Building list of local pool package files to delete"

    # Avoid duplicates (comes from -any packages present in both i686/ and x86_64/)
    sort -u -o "$remote_pool_files" "$remote_pool_files"

    # Sort local pool files to pass the file to comm in the next step
    sort -o "$local_pool_files" "$local_pool_files"

    # Keep lines that only appear in local_pool_files
    comm -13 "$remote_pool_files" "$local_pool_files" > "$pool_files_to_delete"

    # Calculate number of pool files to delete
    number_to_delete="$(wc -l $pool_files_to_delete | cut -d ' ' -f 1)"

    # Fail if there are too many files to delete
    if [[ "$number_to_delete" -gt "$max_delete" ]] ; then
      error "  => ERROR: The number of pool package files to be deleted is ${number_to_delete}, greater than the specified maximum which is ${max_delete}"
    fi

    # Delete pool files
    if [[ $number_to_delete -gt 0 ]] ; then
      if [[ ${no_file_delete} == 1 ]] ; then
        echo "=> Deleting ${number_to_delete} old pool package files"
        find $(cat "$pool_files_to_delete") -print -exec rm -f {} \;
      else
        echo "=> Deletion of pool package files (${number_to_delete}) is disabled. List of files:"
        printf '%s\n' $(cat "$pool_files_to_delete")
      fi
    fi
  fi
fi

echo "=> List of local repositories. Existing files will be hard linked from these instead of being fetched from the remote server."
printf -- '%s\n' "${link_dest[@]}"

if [[ ${db_and_symlinks_update} == 1 ]] ; then

echo "=> Starting to synchronize repository directories (symlinks and db.* files)"

rsync $options --stats --exclude 'mips64el' --delete-after --safe-links "${link_dest_option[@]}" --link-dest="$local_dir" "${repos_array[@]/#/${server}/}" "$local_dir".tmp || error "  => ERROR: rsync terminated with an error code: $?" 

fi

if [[ ${pools_update} == 1 ]] ; then

echo "=> Starting to synchronize package pools from remote server $server"

fi      # end "if [[ ${pools_update} == 1 ]]"


if [[ ${pools_update} == 1 ]] ; then

  rsync $options --stats --exclude '*-mips64el.pkg.tar.*' --safe-links --files-from="$remote_pool_files" "${link_dest_option[@]}" --link-dest="$local_dir" $server "${local_dir}".tmp

fi      # end "if [[ ${pools_update} == 1 ]]"

if [[ ${path_list} ]] ; then
  echo "=> Synchronizing extra paths"
  rsync $options --stats --safe-links "${link_dest_option[@]/%//$path}" --link-dest="$local_dir"/"$path" ${path_list_array[@]/#/${server}/} "${local_dir}".tmp/ || error "  => ERROR: rsync terminated with an error code: $?"
fi

if [[ ${no_snapshot_delete} != 1 ]] ; then

echo "=> DRY-RUN: Delete versions older than the version number: ${oldest_version}."
delete_list=$(find ${base_dir} -regextype sed -maxdepth 1 -regex "${local_dir}-[0-9]\{4\}\.[0-9]\{2\}.[0-9]\{2\}" | head -n -"${oldest_version}") && \
    if [[ ${delete_list} ]] ; then
	echo "DRY_RUN: rm -rf ${delete_list}"
    else
        echo "=> Nothing to delete"
    fi

fi    # closes [[ ${no_snapshot_delete} == 0 ]]

if [[ ${leave_tmp} == 0 ]] ; then
    echo "=> Starting to serve the new repository version"

    if [[ ${date_exact} ]] ; then
        echo "  => Renaming ${local_dir}.tmp to ${local_dir}"-"${date_exact}"
        mv "${local_dir}".tmp "${local_dir}"-"${date_exact}"
    else
        echo "  => Renaming ${local_dir}.tmp to ${current}"
        mv "${local_dir}".tmp "${current}"
    fi
    
    if [[ ${snapshot_symlink_update} == 1 ]] ; then
        cd ${base_dir}

        if [[ ${local_useful} == 1 ]] ; then
            echo "  => Deleting symlink $local_dir"
            rm -rf "${local_dir}"
        fi

        # Create symlink
        if [[ ${date_exact} ]] ; then
            echo "  => Creating symlink ${local_dir} to ${project}-${date_exact}"
            ln -s ${project}-"${date_exact}" ${local_dir}
        else
            echo "  => Creating symlink \"${project}\" to ${current_component}"
            ln -s ${current_component} ${project}
        fi
    fi
fi

rm -f "$remote_pool_files" "$local_pool_files" "$pool_files_to_delete" "$local_dir".old || true

echo "=> Disk space report"
df -h "${base_dir}"

echo "=> ${script_filename} finished successfully. Finish time: $(date --rfc-3339=seconds)"