sync-forks

#!/usr/bin/env bash

set -o errexit
set -o errtrace
set -o functrace
set -o pipefail

declare -r SYNCMIRROR_PREFIX="$(
  readlink -f "$(
    readlink -f "$(
      dirname "$(
        readlink -f "$0"
      )"
    )"
  )"
)"
declare -r SYNCMIRROR_WORK_DIR="$(pwd)"

source "$SYNCMIRROR_PREFIX"/concurrent/concurrent.lib.sh

export CONCURRENT_LIMIT=3
export CONCURRENT_COMPACT=0

if [ "$SYNCMIRROR_PREFIX" == "$SYNCMIRROR_WORK_DIR" ]; then
  echo "cannot create tmp directories in sync mirror's prefix" >&2
  #exit 1
fi

#trap 'Log::Func' DEBUG
#trap -- 'Log::Trace ; exit 1' ERR

SyncMirror::TmpCreate() {
  local -r WorkingDirectory="$1"
  local -i RandomNumber="$RANDOM"

  while [ -d "$WorkingDirectory/.sync-mirror.$RandomNumber" ]; do
    RandomNumber="$RANDOM"
  done

  echo "creating tmp directory: $WorkingDirectory/.sync-mirror.$RandomNumber" >&2
  mkdir "$WorkingDirectory/.sync-mirror.$RandomNumber"

  echo "$WorkingDirectory/.sync-mirror.$RandomNumber"
}

SyncMirror::TmpCleanup() {
  local -r TmpDir="$1"

  if [ -d "$TmpDir" ] && \
     [[ "$TmpDir" =~ ^$SYNCMIRROR_WORK_DIR/\.sync-mirror\..*$ ]]; then
    rm -frv "$TmpDir"
  fi
}

SyncMirror::Log() {
  echo "$@" >&2
  echo "$(date '+%F %R') $@" >> "$SYNCMIRROR_WORK_DIR"/sync-mirrors.errors
}

SyncMirror::CheckRepoSize() {
  local -i Size
  local -r Repo="$1"

  # Find size of repository in bytes
  Size="$(du -s "$Repo" | grep -oP '^[0-9]+')"

  if [ $Size -gt 1074000 ]; then
    SyncMirror::Log "$RepoName is over GitHub's 1GiB limit: $(
      du -hs "$Repo" | grep -oP '^[0-9]+[BKMG]'
    )"
    return 1
  fi
}

SyncMirror::Mirror() {
  local -r RepoName="$1"
  local -r RepoUpstreamUrl="$2"
  local TmpDir

  TmpDir="$(SyncMirror::TmpCreate "$SYNCMIRROR_WORK_DIR")"

  trap "SyncMirror::TmpCleanup $TmpDir" SIGINT SIGTERM
  trap -- "SyncMirror::TmpCleanup $TmpDir" ERR

  echo "cloning: $RepoUpstreamUrl" >&2
  GIT_TERMINAL_PROMPT=0 git clone --bare "$RepoUpstreamUrl" "$TmpDir" || {
    SyncMirror::Log "cloning failed for: $RepoUpstreamUrl"
    return 1
  }

  SyncMirror::CheckRepoSize "$TmpDir" || return 3

  pushd "$TmpDir" > /dev/null
    echo "setting remote origin" >&2
    git remote set-url --push origin \
      "git@github.com:chlorm-forks/${RepoName}.git" || {
      SyncMirror::Log "failed to add upstream remote to: $RepoName"
    }
    echo "fetching origin" >&2
    git fetch -p origin || {
      SyncMirror::Log "git failed to fetch upstream for $RepoName"
    }
  echo "pushing changes" >&2
    # Don't push with --mirror or --prune as both options may overwrite
    # data.  This prevents someone from cleaning the commit history on
    # a repo we are mirroring and then overwriting our mirror with an
    # empty repo.
    git push --all || {
      SyncMirror::Log "git push failed for $RepoName"
    }
  popd > /dev/null

  SyncMirror::TmpCleanup "$TmpDir"
}

if [ -f "$1" ]; then
  MirrorListFile="$1"
else
  MirrorListFile="$SYNCMIRROR_PREFIX/mirror.list"
fi

if [ -n "$1" ]; then
  declare -r Mirror="$1"
fi

echo "Mirror list: $MirrorListFile" >&2

declare -A MirrorList
while read Line; do
  # Don't attempt to eval comments or empty lines
  if [[ "$Line" =~ ^\#.* ]] || [ -z "$Line" ]; then
    continue
  fi
  echo "mirror file line: $Line" >&2
  eval MirrorList+=($Line)
done < "$MirrorListFile"

if [ -n "$Mirror" ]; then
  SyncMirror::Mirror "$Mirror" "${MirrorList["$Mirror"]}"
else
  declare -a ConcurrentArgs
  for i in "${!MirrorList[@]}"; do
    ConcurrentArgs+=(
      '-' "$i" 'SyncMirror::Mirror' "$i" "${MirrorList["$i"]}"
    )
  done

  eval concurrent "${ConcurrentArgs[@]}"
fi

exit 0