os-collect-config/cornfig/cornfig.py

102 lines
3.2 KiB
Python
Executable File

#!/usr/bin/env python
import json
import logging
import os
import pystache
import sys
import tempfile
from optparse import OptionParser
from pystache.context import KeyNotFoundError
from subprocess import Popen, PIPE
logging.basicConfig(format='[%(asctime)s] [%(levelname)s] %(message)s', datefmt='%Y/%m/%d %I:%M:%S %p', level=logging.INFO)
class CornfigException(Exception):
pass
def install_cornfig(config_path, template_root, output_path='/'):
config = read_config(config_path)
tree = build_tree( template_paths(template_root), config )
for path, contents in tree.items():
write_file( os.path.join(output_path, strip_prefix('/', path)), contents)
def write_file(path, contents):
logging.info("writing %s", path)
d = os.path.dirname(path)
if not os.path.exists(d):
os.makedirs(d)
out = open(path, 'w')
out.write(contents)
out.close()
# return a map of filenames->filecontents
def build_tree(templates, config):
res = {}
for in_file, out_file in templates:
res[out_file] = render_template(in_file, config)
return res
def render_template(template, config):
if is_executable(template):
return render_executable(template, config)
else:
return render_moustache(open(template).read(), config)
def is_executable(path):
return os.path.isfile(path) and os.access(path, os.X_OK)
def render_moustache(text, config):
r = pystache.Renderer(missing_tags = 'strict')
return r.render(text, config)
def render_executable(path, config):
p = Popen([path], stdin=PIPE, stdout=PIPE, stderr=PIPE)
stdout, stderr = p.communicate(json.dumps(config))
p.wait()
if p.returncode != 0: raise CornfigException("config script failed: %s\n\nwith output:\n\n%s" % (path, stdout + stderr))
return stdout
def read_config(path):
try:
return json.loads(open(path).read())
except:
raise CornfigException("invalid metadata file: %s" % path)
# given a root directory, return a list of tuples
# containing input and output paths
def template_paths(root):
res = []
for cur_root, subdirs, files in os.walk(root):
for f in files:
inout = ( os.path.join(cur_root, f), os.path.join(strip_prefix(root, cur_root), f) )
res.append(inout)
return res
def strip_prefix(prefix, s):
return s[len(prefix):] if s.startswith(prefix) else s
def usage():
print "Usage:\n cornfig TEMPLATE_ROOT JSON_PATH OUTPUT_ROOT"
sys.exit(1)
def main():
try:
parser = OptionParser(usage="cornfig -t TEMPLATE_ROOT [-m METADATA_FILE] [-o OUT_DIR]")
parser.add_option('-m', '--metadata', dest='metadata_path',
help='path to metadata file (default: /var/lib/cloud/cfn-init-data)',
default='/var/lib/cloud/cfn-init-data')
parser.add_option('-t', '--templates', dest='template_root', help='path to template root directory')
parser.add_option('-o', '--output', dest='out_root', help='root directory for output (default: /)', default='/')
(options, args) = parser.parse_args()
if options.template_root is None: raise CornfigException('missing option --templates')
install_cornfig(options.metadata_path, options.template_root, options.out_root)
except CornfigException as e:
logging.error(e)
sys.exit(1)
if __name__ == '__main__':
main()