Database backup failure alerts on your iPhone

#!/usr/bin/env bash
# Back up a database, copy it off-site, and report every run to ActivitySmith.
set -Eeuo pipefail
DB_NAME="app"
BACKUP_DIR="/var/backups/db"
BACKUP_BUCKET="acme-db-backups"
STORAGE_URL="https://console.example.com/buckets/acme-db-backups"
STREAM_KEY="database-backup"
MIN_FREE_GB=5
STEPS=("Checking disk space" "Dumping database" "Compressing" "Uploading off-site" "Cleaning up")
DUMP_FILE="$BACKUP_DIR/$DB_NAME-$(date -u +%Y-%m-%dT%H%MZ).sql"
BACKUP_FILE="$DUMP_FILE.gz"
LOG_FILE="$BACKUP_DIR/last-run.log"
STARTED_AT=$(date +%s)
CURRENT_STEP=0
mkdir -p "$BACKUP_DIR"
exec > >(tee "$LOG_FILE") 2>&1
activitysmith() {
  curl -fsS --max-time 15 -X "$1" "https://activitysmith.com/api$2" \
    -H "Authorization: Bearer $YOUR_API_KEY" \
    -H "Content-Type: application/json" \
    --data "$3" >/dev/null || echo "ActivitySmith request failed, continuing" >&2
}
live_activity() {
  local status=$1 step=$2 subtitle=$3 color=blue icon=cylinder.split.1x2.fill badge=PROD
  case $status in
    success) color=green; icon=checkmark.circle.fill; badge=$(du -h "$BACKUP_FILE" | cut -f1) ;;
    failure) color=red; icon=exclamationmark.triangle.fill; badge=FAILED ;;
  esac
  jq -n --arg subtitle "$subtitle" --arg color "$color" --arg icon "$icon" --arg badge "$badge" \
    --arg url "$STORAGE_URL" --argjson step "$step" --argjson steps "${#STEPS[@]}" '{
      content_state: {
        title: "Database Backup",
        subtitle: $subtitle,
        type: "segmented_progress",
        number_of_steps: $steps,
        current_step: $step,
        step_colors: (([range(1; $step)] | map("green")) + [$color]),
        color: $color,
        icon: { symbol: $icon, color: $color },
        badge: { title: $badge, color: $color }
      },
      action: { title: "Open Storage", type: "open_url", url: $url }
    }'
}
push_notification() {
  activitysmith POST /push-notification "$(jq -n --arg title "$1" --arg message "$2" --arg url "$STORAGE_URL" \
    '{ title: $title, message: $message, interruption_level: "time-sensitive", redirection: $url }')"
}
step() {
  CURRENT_STEP=$1
  echo "Step $1/${#STEPS[@]}: ${STEPS[$1 - 1]}"
  activitysmith PUT "/live-activity/stream/$STREAM_KEY" "$(live_activity running "$1" "${STEPS[$1 - 1]}")"
}
finish() {
  local status=$? took=$(( $(date +%s) - STARTED_AT ))
  if (( status == 0 )); then
    activitysmith DELETE "/live-activity/stream/$STREAM_KEY" \
      "$(live_activity success "${#STEPS[@]}" "Uploaded in ${took}s")"
  else
    local failed_step="${STEPS[$(( CURRENT_STEP > 0 ? CURRENT_STEP - 1 : 0 ))]}"
    activitysmith DELETE "/live-activity/stream/$STREAM_KEY" \
      "$(live_activity failure "$(( CURRENT_STEP > 0 ? CURRENT_STEP : 1 ))" "Failed: $failed_step")"
    push_notification "Database backup failed" \
      "$failed_step failed: $( { grep -iE 'error|fatal|failed' "$LOG_FILE" || tail -n 1 "$LOG_FILE"; } | tail -n 1 | cut -c1-200)"
  fi
}
trap finish EXIT
# 1. Stop early if the dump will not fit
step 1
free_kb=$(df -Pk "$BACKUP_DIR" | awk 'NR == 2 { print $4 }')
if (( free_kb < MIN_FREE_GB * 1024 * 1024 )); then
  echo "Error: only $(( free_kb / 1024 / 1024 )) GB free in $BACKUP_DIR, need $MIN_FREE_GB GB"
  exit 1
fi
# 2. Dump the database
step 2
pg_dump --format=plain --file "$DUMP_FILE" "$DB_NAME"
# 3. Compress the dump
step 3
gzip --force "$DUMP_FILE"
# 4. Copy it off the server
step 4
aws s3 cp "$BACKUP_FILE" "s3://$BACKUP_BUCKET/$DB_NAME/"
# 5. Keep a week of local copies
step 5
find "$BACKUP_DIR" -name "$DB_NAME-*.sql.gz" -mtime +7 -delete