Convert kopia snapshots to restic snapshots with help of bubblewrap

kopia-to-restic.sh

#! /usr/bin/env nix-shell
#! nix-shell -i bash -p bash restic kopia bubblewrap jq

set -euo pipefail

export KOPIA_CONF_DIR="$XDG_CONFIG_HOME/kopia"
export KOPIA_CONFIG_PATH="$KOPIA_CONF_DIR/kopia-main-repo-on-wdc3.config"
export KOPIA_PASSWORD="$(cat "$KOPIA_CONFIG_PATH.kopia-password" | base64 --decode)"

export RESTIC_PACK_SIZE=128
export RESTIC_PASSWORD_FILE=/run/secrets/restic-backupman-system-data-repo-password
export RESTIC_REPOSITORY=/run/media/sk/backups3/restic-system-data
export RESTIC_READ_CONCURRENCY=1
export GODEBUG=asyncpreemptoff=1

USERNAME=sk
HOST=alien
TMP_DIR=/tmp/kopia-backup

mkdir -p "$TMP_DIR"
umount "$TMP_DIR" || true

for TARGET in "/home/sk/.mozilla" "/home/sk/.thunderbird" "/home/sk/.zotero"; do
  SNAPSHOT_NAME="$USERNAME@$HOST:$TARGET"
  restic snapshots --path="$TARGET"

  IFS=$'\n'
  for line in $(kopia snapshot list "$SNAPSHOT_NAME" --json | jq '.[] | [.startTime, .rootEntry.obj, .source.path] | @sh'); do
    DT=$(echo $line | cut -d"'" -f 2 | xargs date +%Y-%m-%d' '%H:%M:%S -d)
    SNAP_ID=$(echo $line | cut -d"'" -f 4)
    SPATH=$(echo $line | cut -d "'" -f 6)
    echo "$DT, $SNAP_ID, $SPATH"
    if [ "$TARGET" != "$SPATH" ]; then
      echo "$TARGET != $SPATH; skipping"
      continue
    fi
    kopia mount "$SNAP_ID" "$TMP_DIR" &
    pid=$!
    sleep 1
    while [ -z "$(ls -A "$TMP_DIR")" ]; do
      echo "Still not mounted..."
      sleep 1
    done

    bwrap --bind / / --bind "$TMP_DIR" "$TARGET" --chdir "$TARGET" \
      restic backup \
      --no-scan --exclude-caches --ignore-ctime --ignore-inode \
      --exclude-file=$HOME/.resticignore \
      --time "$DT" --host "$HOST" --tag=imported .

    kill $pid
    sleep 1
  done

done

umount "$TMP_DIR" || true