Source code for bokeh.util.dependencies

''' Utilities for checking dependencies

'''
from importlib import import_module
import logging
import shutil
from subprocess import Popen, PIPE

from packaging.version import Version as V

from ..settings import settings

logger = logging.getLogger(__name__)


[docs]def import_optional(mod_name): ''' Attempt to import an optional dependency. Silently returns None if the requested module is not available. Args: mod_name (str) : name of the optional module to try to import Returns: imported module or None, if import fails ''' try: return import_module(mod_name) except ImportError: pass except Exception: msg = "Failed to import optional module `{}`".format(mod_name) logger.exception(msg)
[docs]def import_required(mod_name, error_msg): ''' Attempt to import a required dependency. Raises a RuntimeError if the requested module is not available. Args: mod_name (str) : name of the required module to try to import error_msg (str) : error message to raise when the module is missing Returns: imported module Raises: RuntimeError ''' try: return import_module(mod_name) except ImportError: raise RuntimeError(error_msg)
[docs]def detect_phantomjs(version='2.1'): ''' Detect if PhantomJS is avaiable in PATH, at a minimum version. Args: version (str, optional) : Required minimum version for PhantomJS (mostly for testing) Returns: str, path to PhantomJS ''' if settings.phantomjs_path() is not None: phantomjs_path = settings.phantomjs_path() else: try: phantomjs_path = shutil.which('phantomjs') # Python 2 relies on Environment variable in PATH - attempt to use as follows except AttributeError: phantomjs_path = "phantomjs" try: proc = Popen([phantomjs_path, "--version"], stdout=PIPE, stderr=PIPE) proc.wait() out = proc.communicate() if len(out[1]) > 0: raise RuntimeError('Error encountered in PhantomJS detection: %r' % out[1].decode('utf8')) required = V(version) installed = V(out[0].decode('utf8')) if installed < required: raise RuntimeError('PhantomJS version to old. Version>=%s required, installed: %s' % (required, installed)) except OSError: raise RuntimeError('PhantomJS is not present in PATH. Try "conda install phantomjs" or \ "npm install -g phantomjs-prebuilt"') return phantomjs_path