diff options
| -rw-r--r-- | cloudinit/templater.py | 107 | ||||
| -rw-r--r-- | tests/unittests/test_templating.py | 24 |
2 files changed, 100 insertions, 31 deletions
diff --git a/cloudinit/templater.py b/cloudinit/templater.py index 9922c633..459f241a 100644 --- a/cloudinit/templater.py +++ b/cloudinit/templater.py @@ -20,30 +20,72 @@ # You should have received a copy of the GNU General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. +import collections import re -from Cheetah.Template import Template as CTemplate +try: + from Cheetah.Template import Template as CTemplate + CHEETAH_AVAILABLE = True +except (ImportError, AttributeError): + CHEETAH_AVAILABLE = False -import jinja2 -from jinja2 import Template as JTemplate +try: + import jinja2 + from jinja2 import Template as JTemplate + JINJA_AVAILABLE = True +except (ImportError, AttributeError): + JINJA_AVAILABLE = False from cloudinit import log as logging +from cloudinit import type_utils as tu from cloudinit import util LOG = logging.getLogger(__name__) -DEF_RENDERER = 'cheetah' -RENDERERS = { - 'jinja': (lambda content, params: - JTemplate(content, - undefined=jinja2.StrictUndefined, - trim_blocks=True).render(**params)), - 'cheetah': (lambda content, params: - CTemplate(content, searchList=[params]).respond()), -} TYPE_MATCHER = re.compile(r"##\s*template:(.*)", re.I) +BASIC_MATCHER = re.compile(r'\$\{([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'. + """ + + def replacer(match): + path = collections.deque(match.group(1).split(".")) + selected_params = params + while len(path) > 1: + key = path.popleft() + if not isinstance(selected_params, dict): + raise TypeError("Can not traverse into" + " non-dictionary '%s' of type %s while" + " looking for subkey '%s'" + % (selected_params, + tu.obj_name(selected_params), + key)) + selected_params = selected_params[key] + key = path.popleft() + if not isinstance(selected_params, dict): + raise TypeError("Can not extract key '%s' from non-dictionary" + " '%s' of type %s" + % (key, selected_params, + tu.obj_name(selected_params))) + return str(selected_params[key]) + + return BASIC_MATCHER.sub(replacer, content) def detect_template(text): + + def cheetah_render(content, params): + return CTemplate(content, searchList=[params]).respond() + + def jinja_render(content, params): + return JTemplate(content, + undefined=jinja2.StrictUndefined, + trim_blocks=True).render(**params) + if text.find("\n") != -1: ident, rest = text.split("\n", 1) else: @@ -51,14 +93,32 @@ def detect_template(text): rest = '' type_match = TYPE_MATCHER.match(ident) if not type_match: - return (DEF_RENDERER, text) - template_type = type_match.group(1).lower().strip() - if template_type not in RENDERERS: - raise ValueError("Unknown template type '%s' requested" - % template_type) + if not CHEETAH_AVAILABLE: + LOG.warn("Cheetah not available as the default renderer for" + " unknown template, reverting to the basic renderer.") + return ('basic', basic_render, text) + else: + return ('cheetah', cheetah_render, text) else: - return (template_type, rest) - + template_type = type_match.group(1).lower().strip() + if template_type not in ('jinja', 'cheetah', 'basic'): + raise ValueError("Unknown template rendering type '%s' requested" + % template_type) + if template_type == 'jinja' and not JINJA_AVAILABLE: + LOG.warn("Jinja not available as the selected renderer for" + " desired template, reverting to the basic renderer.") + return ('basic', basic_render, rest) + elif template_type == 'jinja' and JINJA_AVAILABLE: + return ('jinja', jinja_render, rest) + if template_type == 'cheetah' and not CHEETAH_AVAILABLE: + LOG.warn("Cheetah not available as the selected renderer for" + " desired template, reverting to the basic renderer.") + return ('basic', basic_render, rest) + elif template_type == 'cheetah' and CHEETAH_AVAILABLE: + return ('cheetah', cheetah_render, rest) + # Only thing left over is the basic renderer (it is always available). + return ('basic', basic_render, rest) + def render_from_file(fn, params): return render_string(util.load_file(fn), params) @@ -72,10 +132,5 @@ def render_to_file(fn, outfn, params, mode=0644): def render_string(content, params): if not params: params = {} - try: - renderer, content = detect_template(content) - except ValueError as e: - renderer = DEF_RENDERER - LOG.warn("%s, using renderer %s", e, renderer) - LOG.debug("Rendering %s using renderer '%s'", content, renderer) - return RENDERERS[renderer](content, params) + template_type, renderer, content = detect_template(content) + return renderer(content, params) diff --git a/tests/unittests/test_templating.py b/tests/unittests/test_templating.py index b4f425a8..c3faac3d 100644 --- a/tests/unittests/test_templating.py +++ b/tests/unittests/test_templating.py @@ -18,21 +18,35 @@ from tests.unittests import helpers as test_helpers - from cloudinit import templater class TestTemplates(test_helpers.TestCase): + def test_render_basic(self): + in_data = """ +${b} + +c = d +""" + in_data = in_data.strip() + expected_data = """ +2 + +c = d +""" + out_data = templater.basic_render(in_data, {'b': 2}) + self.assertEqual(expected_data.strip(), out_data) + def test_detection(self): blob = "## template:cheetah" - (template_type, contents) = templater.detect_template(blob) - self.assertEqual("cheetah", template_type) + (template_type, renderer, contents) = templater.detect_template(blob) + self.assertIn("cheetah", template_type) self.assertEqual("", contents.strip()) blob = "blahblah $blah" - (template_type, contents) = templater.detect_template(blob) - self.assertEqual("cheetah", template_type) + (template_type, renderer, contents) = templater.detect_template(blob) + self.assertIn("cheetah", template_type) self.assertEquals(blob, contents) blob = '##template:something-new' |