mostly there, no ui yet.

cornfig/cornfig.py

@@ -1,11 +1,56 @@
+import json
 import os
+import pystache
+import subprocess
+from pystache.context import KeyNotFoundError
 
-#def process_template(in_f, out_f):
+class CornfigException(Exception):
+  pass
 
+def install_cornfig(config_path, template_root):
+  config = read_config(config_path)
+  for in_file, out_file in template_paths(template_root):
+    print render_template(in_file, config)
+
+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):
+  try:
+    return subprocess.check_output([path], env=flatten(config))
+  except subprocess.CalledProcessError as e:
+    raise CornfigException("config script failed: %s\n\nwith output:\n\n%s" % (path, e.output))
 
 def read_config(path):
   return json.loads(open(path).read())
 
+def flatten(d, prefix='', res=None):
+  res = res or {}
+  for k, v in d.items():
+    key = (prefix + '.' + k) if len(prefix) > 0 else k
+    if isinstance(v, str):
+      res[key] = v
+    elif isinstance(v, dict):
+       res = dict(res.items() + flatten(v, key, res).items())
+    else:
+      raise CornfigException("expected only strings and hashes in config.")
+  return res
 
 # given a root directory, return a list of tuples
 # containing input and output paths

tests/cornfig_tests.py

@@ -1,9 +1,21 @@
+import json
+import os
+import tempfile
 from nose.tools import *
 from cornfig.cornfig import *
-import os
 
 TEMPLATES = os.path.join(os.path.dirname(__file__), 'templates')
-TEMPLATE_PATHS = ["/etc/keystone/keystone.conf"]
+TEMPLATE_PATHS = [
+    "/etc/glance/script.conf",
+    "/etc/keystone/keystone.conf"
+  ]
+
+CONFIG = {
+  "x": "foo",
+  "database": {
+    "url": "sqlite:///blah"
+  }
+}
 
 def setup():
   pass
@@ -11,15 +23,57 @@ def setup():
 def teardown():
   pass
 
-def test_template_paths():
-  expected = map(lambda p: (os.path.join(TEMPLATES, p[1:]), p), TEMPLATE_PATHS)
-  assert template_paths(TEMPLATES) == expected
+def template(relpath):
+  return os.path.join(TEMPLATES, relpath[1:])
 
-@raises(Exception)
+def test_build_tree():
+  print flatten(CONFIG)
+  assert_equals( build_tree(template_paths(TEMPLATES), CONFIG),
+    {
+      "/etc/keystone/keystone.conf": "[foo]\ndatabase = sqlite:///blah\n",
+      "/etc/glance/script.conf": "foo\n"
+    })
+
+def test_flatten():
+  assert_equals( flatten({"x": {"a": "b", "c": "d"}, "y": "z"}), {"x.a": "b", "x.c": "d", "y": "z"} )
+
+def test_render_template():
+  # execute executable files, moustache non-executables
+  assert render_template(template("/etc/glance/script.conf"), {"x": "abc"}) == "abc\n"
+  assert_raises(CornfigException, render_template, template("/etc/glance/script.conf"), {})
+
+def test_render_moustache():
+  assert_equals( render_moustache("ab{{x.a}}cd", {"x": {"a": "123"}}), "ab123cd" )
+
+@raises(KeyNotFoundError)
+def test_render_moustache_bad_key():
+  render_moustache("{{badkey}}", {})
+
+def test_render_executable():
+  params = {"x": "foo"}
+  assert render_executable(template("/etc/glance/script.conf"), params) == "foo\n"
+
+@raises(CornfigException)
+def test_render_executable_failure():
+  render_executable(template("/etc/glance/script.conf"), {})
+
+def test_template_paths():
+  expected = map(lambda p: (template(p), p), TEMPLATE_PATHS)
+  assert_equals( template_paths(TEMPLATES), expected)
+
+def test_read_config():
+  with tempfile.NamedTemporaryFile() as t:
+    d = {"a": {"b": ["c", "d"] } }
+    t.write(json.dumps(d))
+    t.flush()
+    assert_equals( read_config(t.name), d )
+
+@raises(ValueError)
 def test_read_config_bad_json():
-  with tempfile.TemporaryFile() as t:
+  with tempfile.NamedTemporaryFile() as t:
     t.write("{{{{")
-    read_config(t.path)
+    t.flush()
+    read_config(t.name)
 
 @raises(Exception)
 def test_read_config_no_file():

tests/templates/etc/glance/script.conf

@@ -0,0 +1,4 @@
+#!/bin/sh
+set -u
+echo $x
+

tests/templates/etc/keystone/keystone.conf

@@ -1,2 +1,2 @@
-adf
-asdf
+[foo]
+database = {{database.url}}