TemplateNotFound(template) with Google App Engine & Jinja2 - google-app-engine

Question

I'm getting a TemplateNotFound error on Google App Engine with Jinja2 (complete stack trace below.)
What I expect to see is the index.html with the "greet" variable passed to the index.html template file. What I don't understand is why I get the template not found error when the path to index.html in the TraceBack is correct.
What I've tried...
tried a relative path by taking out "os.path.dirname(file)" in template path.
using "template" instead of themes as a directory name.
Here is my code.
app.yaml
application: codemywayout
version: 1
runtime: python27
api_version: 1
threadsafe: true
handlers:
- url: /admin/.*
script: admin.app
login: admin
- url: /static/([^/]+)/(.*)
static_files: template/\1/static/\2
upload: static/.*
- url: /favicon\.ico
static_files: favicon.ico
upload: favicon\.ico
- url: .*
script: static.app
builtins:
- remote_api: on
libraries:
- name: webapp2
version: "2.5.1"
- name: jinja2
version: latest
admin.py
from google.appengine.ext import db
import webapp2
import jinja2
import os
import fix_path
import config
def render_template(template_name, template_vals=None, theme=None):
template_path = os.path.join(os.path.dirname(__file__) , \
"themes", theme or config.theme, template_name)
env = jinja2.Environment(
loader=jinja2.FileSystemLoader(template_path))
return env.get_template(template_path, template_vals or {})
class BlogPost(db.Model):
title = db.StringProperty()
body = db.StringProperty()
def render(self):
template_vals = {
'config': config,
'post': self,
}
return render_template("post.html", template_vals)
class BaseHandler(webapp2.RequestHandler):
def render_to_response(self, template_name, \
template_vals=None, theme=None):
template_name = os.path.join("admin", template_name)
self.response.out.write(render_template(template_name,\
template_vals, theme))
class AdminHandler(BaseHandler):
def get(self):
greet = "hello"
template_vals = {
'greet': greet
}
self.render_to_response("index.html", template_vals)
config.py
# Name of the blog
blog_name = 'My Blog'
# Selects the theme to use. Theme names correspond to directories under
# the 'themes' directory, containing templates and static content.
theme = 'default'
# Defines the URL organization to use for blog postings. Valid substitutions:
# slug - the identifier for the post, derived from the title
# year - the year the post was published in
# month - the month the post was published in
# day - the day the post was published in
# URL Options
# post_path_format = '/%(year)d/%(month)02d/%(slug)s'
post_path_format = '/%(slug)s'
TraceBack
Traceback (most recent call last):
File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1536, in __call__
rv = self.handle_exception(request, response, e)
File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1530, in __call__
rv = self.router.dispatch(request, response)
File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1278, in default_dispatcher
return route.handler_adapter(request, response)
File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1102, in __call__
return handler.dispatch()
File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 572, in dispatch
return self.handle_exception(e, self.app.debug)
File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 570, in dispatch
return method(*args, **kwargs)
File "C:\Users\john\webdev\workspace\codemywayout\admin.py", line 49, in get
self.render_to_response("index.html", template_vals)
File "C:\Users\john\webdev\workspace\codemywayout\admin.py", line 34, in render_to_response
template_vals, theme))
File "C:\Users\john\webdev\workspace\codemywayout\admin.py", line 14, in render_template
return env.get_template(template_path, template_vals or {})
File "C:\Users\john\webdev\google\lib\jinja2\jinja2\environment.py", line 719, in get_template
return self._load_template(name, self.make_globals(globals))
File "C:\Users\john\webdev\google\lib\jinja2\jinja2\environment.py", line 693, in _load_template
template = self.loader.load(self, name, globals)
File "C:\Users\john\webdev\google\lib\jinja2\jinja2\loaders.py", line 115, in load
source, filename, uptodate = self.get_source(environment, name)
File "C:\Users\john\webdev\google\lib\jinja2\jinja2\loaders.py", line 162, in get_source
pieces = split_template_path(template)
File "C:\Users\john\webdev\google\lib\jinja2\jinja2\loaders.py", line 33, in split_template_path
raise TemplateNotFound(template)
TemplateNotFound: C:\Users\john\webdev\workspace\codemywayout\themes\default\admin\index.html

Answer 1

I hope your not trying to load the Jinja template from the same path as your static files
static_files: template/\1/static/\2
As that path is not accessible to your application.
I would try and log the path that Jinja is trying to load the template from to help you understand where it is trying to load the template.

Answer 2

If you look at C:\Users\john\webdev\google\lib\jinja2\jinja2\loaders.py line 33 you can probably set a pdb breakpoint import pdb; pdb.set_trace( ) and see what's going on.
I'm using the SDK source distribution on a Mac, but if your code is the same as what I see, it's:
def split_template_path(template):
"""Split a path into segments and perform a sanity check. If it detects
'..' in the path it will raise a `TemplateNotFound` error.
"""
pieces = []
for piece in template.split('/'):
if path.sep in piece \
or (path.altsep and path.altsep in piece) or \
piece == path.pardir:
raise TemplateNotFound(template)
elif piece and piece != '.':
pieces.append(piece)
return pieces
Note the for piece in template.split('/') where it splits on '/' instead of path.sep. I suspect that your input is a C:\Path\to\file.html in which case piece is the entire path, adn path.sep (\ on windows) is indeed in piece, which gives a TemplateNotFound error.
Instead of template_name = os.path.join("admin", template_name) you could try template_name = 'admin/%s' % template_name, don't include template_name in the template_path and pass template_name instead of template_path into env.get_template(template_name, template_vals or {}) as loaders.py line 162 indicates that it looks for template_name in template_path
Your code, modified but untested would look something like
from google.appengine.ext import db
import webapp2
import jinja2
import os
import fix_path
import config
def render_template(template_name, template_vals=None, theme=None):
template_path = os.path.join(os.path.dirname(__file__) , \
"themes", theme or config.theme)
env = jinja2.Environment(
loader=jinja2.FileSystemLoader(template_path))
return env.get_template(template_name, template_vals or {})
class BlogPost(db.Model):
title = db.StringProperty()
body = db.StringProperty()
def render(self):
template_vals = {
'config': config,
'post': self,
}
return render_template("post.html", template_vals)
class BaseHandler(webapp2.RequestHandler):
def render_to_response(self, template_name, \
template_vals=None, theme=None):
template_name = "admin/%s" % template_name
self.response.out.write(render_template(template_name,\
template_vals, theme))
class AdminHandler(BaseHandler):
def get(self):
greet = "hello"
template_vals = {
'greet': greet
}
self.render_to_response("index.html", template_vals)