Retry a command with exponential backoff

#!/usr/bin/env bash
# Retry a command with exponential backoff until it succeeds.
set -euo pipefail

retry() {
  local max_attempts=$1
  local delay=$2
  shift 2
  local attempt=1

  until "$@"; do
    if ((attempt >= max_attempts)); then
      printf 'giving up after %d attempts: %s\n' "$attempt" "$*" >&2
      return 1
    fi
    printf 'attempt %d failed, retrying in %ss\n' "$attempt" "$delay" >&2
    sleep "$delay"
    # Double the delay, capped at 30 seconds.
    delay=$((delay * 2 > 30 ? 30 : delay * 2))
    attempt=$((attempt + 1))
  done
}

retry 5 1 curl --fail --silent --show-error -o /dev/null https://example.com/health