Merge pull request #4 from echohead/key-types

Allow printing of metadata values with '--key KEY --type TYPE'

os_config_applier/config_exception.py

@@ -0,0 +1,2 @@
+class ConfigException(Exception):
+  pass

os_config_applier/os_config_applier.py

@@ -8,6 +8,8 @@ import tempfile
 from argparse import ArgumentParser
 from pystache.context import KeyNotFoundError
 from subprocess import Popen, PIPE
+from value_types import *
+from config_exception import *
 
 TEMPLATES_DIR = os.environ.get('OS_CONFIG_APPLIER_TEMPLATES',
                                '/opt/stack/os-config-applier/templates')
@@ -19,6 +21,18 @@ def install_config(config_path, template_root, output_path, validate, subhash=No
     for path, contents in tree.items():
       write_file( os.path.join(output_path, strip_prefix('/', path)), contents)
 
+def print_key(config_path, key, type_name):
+  config = read_config(config_path)
+  keys = key.split('.')
+  for key in keys:
+    try:
+      config = config[key]
+    except KeyError:
+      raise KeyError('key %s does not exist in %s' % (key, config_path))
+  ensure_type(config, type_name)
+  print config
+
+
 def write_file(path, contents):
   logger.info("writing %s", path)
   d = os.path.dirname(path)
@@ -101,6 +115,10 @@ def parse_opts(argv):
                         help='Print templates root and exit.')
     parser.add_argument('-s', '--subhash',
                         help='use the sub-hash named by this key, instead of the full metadata hash')
+    parser.add_argument('--key', metavar='KEY', default=None,
+                        help='print the specified key and exit. (may be used with --type)')
+    parser.add_argument('--type', default='default',
+                        help='exit with error if the specified --key does not match type. Valid types are <int|default|raw>')
     opts = parser.parse_args(argv[1:])
 
     return opts
@@ -114,18 +132,19 @@ def main(argv=sys.argv):
   try:
     if opts.templates is None:
         raise ConfigException('missing option --templates')
-    if not os.access(opts.output, os.W_OK):
-        raise ConfigException("you don't have permission to write to '%s'" % opts.output)
 
-    install_config(opts.metadata, opts.templates, opts.output,
-                   opts.validate, opts.subhash)
-    logger.info("success")
+    if opts.key:
+      print_key(opts.metadata, opts.key, opts.type)
+    else:
+      if not os.access(opts.output, os.W_OK):
+        raise ConfigException("you don't have permission to write to '%s'" % opts.output)
+      install_config(opts.metadata, opts.templates, opts.output,
+                     opts.validate)
+      logger.info("success")
   except ConfigException as e:
     logger.error(e)
     sys.exit(1)
-
-class ConfigException(Exception):
-  pass
+  sys.exit(0)
 
 # logginig
 LOG_FORMAT = '[%(asctime)s] [%(levelname)s] %(message)s'

os_config_applier/value_types.py

@@ -0,0 +1,15 @@
+import re
+from config_exception import ConfigException
+
+TYPES = {
+  "int": "^[0-9]+$",
+  "default": "^[A-Za-z0-9]+$",
+  "raw": "."
+}
+
+def ensure_type(string_value, type_name='default'):
+  if type_name not in TYPES:
+    raise ValueError("requested validation of unknown type: %s" % type_name)
+  if not re.match(TYPES[type_name], string_value):
+    raise ConfigException("cannot interpret value '%s' as type %s" % (string_value, type_name))
+  return string_value

tests/os_config_applier_tests.py

@@ -1,8 +1,10 @@
 import json
 import os
+import subprocess
 import tempfile
 from StringIO import StringIO
 from nose.tools import *
+from os_config_applier.config_exception import *
 from os_config_applier.os_config_applier import *
 
 # example template tree
@@ -32,10 +34,12 @@ def setup():
 def teardown():
   pass
 
+def main_path():
+  return os.path.dirname(os.path.realpath(__file__)) + '/../os_config_applier/os_config_applier.py'
+
 def template(relpath):
   return os.path.join(TEMPLATES, relpath[1:])
 
-
 def test_install_config():
   t = tempfile.NamedTemporaryFile()
   t.write(json.dumps(CONFIG))
@@ -47,6 +51,28 @@ def test_install_config():
     assert os.path.exists(full_path)
     assert_equal( open(full_path).read(), contents )
 
+def test_print_key():
+  t = tempfile.NamedTemporaryFile()
+  t.write(json.dumps(CONFIG))
+  t.flush()
+  out = subprocess.check_output([main_path(), '--metadata', t.name, '--key', 'database.url', '--type', 'raw'])
+  assert_equals(CONFIG['database']['url'], out.rstrip())
+
+@raises(subprocess.CalledProcessError)
+def test_print_key_missing():
+  t = tempfile.NamedTemporaryFile()
+  t.write(json.dumps(CONFIG))
+  t.flush()
+  out = subprocess.check_output([main_path(), '--metadata', t.name, '--key', 'does.not.exist'])
+
+@raises(subprocess.CalledProcessError)
+def test_print_key_wrong_type():
+  t = tempfile.NamedTemporaryFile()
+  t.write(json.dumps(CONFIG))
+  t.flush()
+  out = subprocess.check_output([main_path(), '--metadata', t.name, '--key', 'x', '--type', 'int'])
+
+
 def test_build_tree():
   assert_equals( build_tree(template_paths(TEMPLATES), CONFIG), OUTPUT )
 

tests/value_type_tests.py

@@ -0,0 +1,18 @@
+from nose.tools import *
+from os_config_applier.os_config_applier import *
+from os_config_applier.config_exception import *
+from os_config_applier.value_types import *
+
+@raises(ValueError)
+def test_unknown_type():
+  ensure_type("foo", "badtype")
+
+def test_int():
+  assert_equals("123", ensure_type("123", "int"))
+
+def test_defualt():
+  assert_equals("foobar", ensure_type("foobar", "default"))
+
+@raises(ConfigException)
+def test_default_bad():
+  ensure_type("foo\nbar", "default")