wskprop.py

#!/usr/bin/env python
"""Helper methods for whisk properties.

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
"""
import os


def propfile(base):
    if base != '':
        filename = '%s/whisk.properties' % base
        if os.path.isfile(filename) and os.path.exists(filename):
            return filename
        else:
            parent = os.path.dirname(base)
            return propfile(parent) if parent != base else ''
    else:
        return ''


def importPropsIfAvailable(filename):
    thefile = (open(filename, 'r') if os.path.isfile(filename) and
               os.path.exists(filename) else [])
    return importProps(thefile)


def importProps(stream):
    props = {}
    for line in stream:
        parts = line.split('=')
        if len(parts) >= 1:
            key = parts[0].strip()
        if len(parts) >= 2:
            val = parts[1].strip()
        if key != '' and val != '':
            props[key.upper().replace('.', '_')] = val
        elif key != '':
            props[key.upper().replace('.', '_')] = ''
    return props


# Returns a triple of (length(invalidProperties), requiredProperties,
# deferredInfo) prints a message if a required property is not found
def checkRequiredProperties(requiredPropertiesByName, properties):
    """Return a tuple describing the requested required properties."""
    requiredPropertiesByValue = [getPropertyValue(key, properties) for key
                                 in requiredPropertiesByName]
    requiredProperties = dict(zip(requiredPropertiesByName,
                                  requiredPropertiesByValue))
    invalidProperties = [key for key in requiredPropertiesByName if
                         requiredProperties[key] is None]
    deferredInfo = ''
    for key, value in requiredProperties.items():
        if value in (None, ''):
            print('property "%s" not found in environment or '
                  'property file' % key)
        else:
            deferredInfo += 'using %(key)s = %(value)s\n' % {'key': key,
                                                             'value': value}
    return (len(invalidProperties) == 0, requiredProperties, deferredInfo)


def getPropertyValue(key, properties):
    evalue = os.environ.get(key)
    value = (evalue if evalue is not None and evalue is not ''
             else properties[key] if key in properties else None)
    return value