Add non braces matching and a few more tests

cloudinit/templater.py

@@ -42,18 +42,25 @@ from cloudinit import util
 
 LOG = logging.getLogger(__name__)
 TYPE_MATCHER = re.compile(r"##\s*template:(.*)", re.I)
-BASIC_MATCHER = re.compile(r'\$\{([A-Za-z0-9_.]+)\}')
+BASIC_MATCHER = re.compile(r'\$\{([A-Za-z0-9_.]+)\}|\$([A-Za-z0-9_.]+)')
 
 
 def basic_render(content, params):
     """This does simple replacement of bash variable like templates.
 
-    It identifies patterns like ${a} and can also identify patterns like
-    ${a.b} which will look for a key 'b' in the dictionary rooted by key 'a'.
+    It identifies patterns like ${a} or $a and can also identify patterns like
+    ${a.b} or $a.b which will look for a key 'b' in the dictionary rooted
+    by key 'a'.
     """
 
     def replacer(match):
-        path = collections.deque(match.group(1).split("."))
+        # Only 1 of the 2 groups will actually have a valid entry.
+        name = match.group(1)
+        if name is None:
+            name = match.group(2)
+        if name is None:
+            raise RuntimeError("Match encountered but no valid group present")
+        path = collections.deque(name.split("."))
         selected_params = params
         while len(path) > 1:
             key = path.popleft()

tests/unittests/test_templating.py

@@ -68,3 +68,39 @@ $a,$b'''
         blob = '''$a,$b'''
         c = templater.render_string(blob, {"a": 1, "b": 2})
         self.assertEquals("1,2", c)
+
+    def test_render_basic_deeper(self):
+        hn = 'myfoohost.yahoo.com'
+        expected_data = "h=%s\nc=d\n" % hn
+        in_data = "h=$hostname.canonical_name\nc=d\n"
+        params = {
+            "hostname": {
+                "canonical_name": hn,
+            },
+        }
+        out_data = templater.render_string(in_data, params)
+        self.assertEqual(expected_data, out_data)
+
+    def test_render_basic_no_parens(self):
+        hn = "myfoohost"
+        in_data = "h=$hostname\nc=d\n"
+        expected_data = "h=%s\nc=d\n" % hn
+        out_data = templater.basic_render(in_data, {'hostname': hn})
+        self.assertEqual(expected_data, out_data)
+
+    def test_render_basic_parens(self):
+        hn = "myfoohost"
+        in_data = "h = ${hostname}\nc=d\n"
+        expected_data = "h = %s\nc=d\n" % hn
+        out_data = templater.basic_render(in_data, {'hostname': hn})
+        self.assertEqual(expected_data, out_data)
+
+    def test_render_basic2(self):
+        mirror = "mymirror"
+        codename = "zany"
+        in_data = "deb $mirror $codename-updates main contrib non-free"
+        ex_data = "deb %s %s-updates main contrib non-free" % (mirror, codename)
+
+        out_data = templater.basic_render(in_data,
+        {'mirror': mirror, 'codename': codename})
+        self.assertEqual(ex_data, out_data)