text: """Let's Encrypt constants."""
  import os
  import logging
  
  from acme import challenges
  
  
  SETUPTOOLS_PLUGINS_ENTRY_POINT = "letsencrypt.plugins"
  """Setuptools entry point group name for plugins."""
  
  CLI_DEFAULTS = dict(
      config_files=[
          "/etc/letsencrypt/cli.ini",
          # http://freedesktop.org/wiki/Software/xdg-user-dirs/
          os.path.join(os.environ.get("XDG_CONFIG_HOME", "~/.config"),
                       "letsencrypt", "cli.ini"),
      ],
      verbose_count=-(logging.WARNING / 10),
      server="https://acme-v01.api.letsencrypt.org/directory",
      rsa_key_size=2048,
      rollback_checkpoints=1,
      config_dir="/etc/letsencrypt",
      work_dir="/var/lib/letsencrypt",
      logs_dir="/var/log/letsencrypt",
      no_verify_ssl=False,
      http01_port=challenges.HTTP01Response.PORT,
      tls_sni_01_port=challenges.TLSSNI01Response.PORT,
  
      auth_cert_path="./cert.pem",
      auth_chain_path="./chain.pem",
      strict_permissions=False,
  )
  """Defaults for CLI flags and `.IConfig` attributes."""
  
  
  RENEWER_DEFAULTS = dict(
      renewer_enabled="yes",
      renew_before_expiry="30 days",
      deploy_before_expiry="20 days",
  )
  """Defaults for renewer script."""
  
  
  EXCLUSIVE_CHALLENGES = frozenset([frozenset([
      challenges.TLSSNI01, challenges.HTTP01])])
  """Mutually exclusive challenges."""
  
  
  ENHANCEMENTS = ["redirect", "http-header", "ocsp-stapling", "spdy"]
  """List of possible :class:`letsencrypt.interfaces.IInstaller`
  enhancements.
  
  List of expected options parameters:
  - redirect: None
  - http-header: TODO
  - ocsp-stapling: TODO
  - spdy: TODO
  
  """
  
  ARCHIVE_DIR = "archive"
  """Archive directory, relative to `IConfig.config_dir`."""
  
  CONFIG_DIRS_MODE = 0o755
  """Directory mode for ``.IConfig.config_dir`` et al."""
  
  ACCOUNTS_DIR = "accounts"
  """Directory where all accounts are saved."""
  
  BACKUP_DIR = "backups"
  """Directory (relative to `IConfig.work_dir`) where backups are kept."""
  
  CSR_DIR = "csr"
  """See `.IConfig.csr_dir`."""
  
  IN_PROGRESS_DIR = "IN_PROGRESS"
  """Directory used before a permanent checkpoint is finalized (relative to
  `IConfig.work_dir`)."""
  
  KEY_DIR = "keys"
  """Directory (relative to `IConfig.config_dir`) where keys are saved."""
  
  LIVE_DIR = "live"
  """Live directory, relative to `IConfig.config_dir`."""
  
  TEMP_CHECKPOINT_DIR = "temp_checkpoint"
  """Temporary checkpoint directory (relative to `IConfig.work_dir`)."""
  
  RENEWAL_CONFIGS_DIR = "renewal"
  """Renewal configs directory, relative to `IConfig.config_dir`."""
  
  RENEWER_CONFIG_FILENAME = "renewer.conf"
  """Renewer config file name (relative to `IConfig.config_dir`)."""
  