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#!/usr/bin/env python
###############################################################################
# Copyright (c) 2016 Ericsson AB and others.
# peter.barabas@ericsson.com
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Apache License, Version 2.0
# which accompanies this distribution, and is available at
# http://www.apache.org/licenses/LICENSE-2.0
###############################################################################
import io
import re
import yaml
import urllib2
from common import(
err,
ArgParser,
)
TAG_START = '%{'
TAG_END = '}'
DELIMITER = '/'
class Templater(object):
def __init__(self, base_file, template_file, output_file):
self.template_file = template_file
self.output_file = output_file
self.base = self.load_yaml(base_file)
def is_url(self, filespec):
regex = re.compile('^([^/:]+)://')
return re.search(regex, filespec)
def load_template(self, filespec):
try:
if(self.is_url(filespec)):
response = urllib2.urlopen(filespec)
return response.read()
else:
with io.open(filespec) as f:
return f.readlines()
except Exception as error:
err('Error opening template file: %s' % error)
def load_yaml(self, filespec):
try:
if(self.is_url(filespec)):
response = urllib2.urlopen(filespec)
return yaml.load(response)
else:
with io.open(filespec) as f:
return yaml.load(f)
except Exception as error:
err('Error opening YAML file: %s' % error)
def save_yaml(self, filename, content):
try:
with io.open(filename, 'w') as yaml_file:
yaml_file.write(content)
except Exception as error:
err('Error writing YAML file: %s' % error)
def get_indent(self, line):
return len(line) - len(line.lstrip(' '))
def format_fragment(self, fragment, indent):
result = ''
is_first_line = True
for line in fragment.splitlines():
# Skip indenting the first line as it is already indented
if is_first_line:
line += '\n'
is_first_line = False
else:
line = ' ' * indent + line + '\n'
result += line
return result.rstrip('\n')
def format_substitution(self, string):
if isinstance(string, basestring):
return string
else:
return yaml.dump(string, default_flow_style=False)
def parse_interface_tag(self, tag):
# Remove 'interface(' prefix, trailing ')' and split arguments
args = tag[len('interface('):].rstrip(')').split(',')
if len(args) == 1 and not args[0]:
err('No arguments for interface().')
elif len(args) == 2 and (not args[0] or not args[1]):
err('Empty argument for interface().')
elif len(args) > 2:
err('Too many arguments for interface().')
else:
return args
def get_interface_from_network(self, interfaces, network):
nics = self.base[interfaces]
for nic in nics:
if network in nics[nic]:
return nic
err('Network not found: %s' % network)
def get_role_interfaces(self, role):
nodes = self.base['nodes']
for node in nodes:
if role in node['role']:
return node['interfaces']
err('Role not found: %s' % role)
def lookup_interface(self, args):
nodes = self.base['nodes']
if len(args) == 1:
interfaces = nodes[0]['interfaces']
if len(args) == 2:
interfaces = self.get_role_interfaces(args[1])
return self.get_interface_from_network(interfaces, args[0])
def parse_include_tag(self, tag):
# Remove 'include(' prefix and trailing ')'
filename = tag[len('include('):].rstrip(')')
if not filename:
err('No argument for include().')
return filename
def include_file(self, filename):
fragment = self.load_yaml(filename)
return yaml.dump(fragment, default_flow_style=False)
def parse_tag(self, tag, indent):
fragment = ''
if 'interface(' in tag:
args = self.parse_interface_tag(tag)
fragment = self.lookup_interface(args)
elif 'include(' in tag:
filename = self.parse_include_tag(tag)
fragment = self.include_file(filename)
else:
path = tag.split(DELIMITER)
fragment = self.base
for i in path:
if i in fragment:
fragment = fragment.get(i)
else:
err('Error: key "%s" does not exist in base YAML file' % i)
fragment = self.format_substitution(fragment)
return self.format_fragment(fragment, indent)
def run(self):
result = ''
regex = re.compile(re.escape(TAG_START) + r'([a-z].+)' + re.escape(TAG_END),
flags=re.IGNORECASE)
for line in self.load_template(self.template_file):
indent = self.get_indent(line)
result += re.sub(regex,
lambda match: self.parse_tag(match.group(1), indent),
line)
self.save_yaml(self.output_file, result)
def parse_arguments():
description = '''Process 'template_file' using 'base_file' as source for
template variable substitution and write the results to 'output_file'.'''
parser = ArgParser(prog='python %s' % __file__,
description=description)
parser.add_argument('base_file',
help='Base YAML file or URL')
parser.add_argument('template_file',
help='Template file or URL')
parser.add_argument('output_file',
help='Output filename')
args = parser.parse_args()
return(args.base_file, args.template_file, args.output_file)
def main():
base_file, template_file, output_file = parse_arguments()
templater = Templater(base_file, template_file, output_file)
templater.run()
if __name__ == '__main__':
main()
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