Cause of jinja2.exceptions.TemplateNotFound even when using just jinja2

Question

The cause of the problem is obvious after the fact, but I'd like to share the not-too-obvious cause here.

When running code such as

import jinja2

templateLoader = jinja2.FileSystemLoader(searchpath=".")
templateEnv = jinja2.Environment(loader=templateLoader,
                                 trim_blocks=True,
                                 lstrip_blocks=True)

htmlTemplateFile = 'file.jinja.html'
htmlTemplate = templateEnv.get_template(htmlTemplateFile)

if you get this problem:

Traceback (most recent call last):
    ...
  File "file.py", line xyz, in some_func
    htmlTemplate = templateEnv.get_template(htmlTemplateFile)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/jinja2/environment.py", line 812, in get_template
    return self._load_template(name, self.make_globals(globals))
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/jinja2/environment.py", line 774, in _load_template
    cache_key = self.loader.get_source(self, name)[1]
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/jinja2/loaders.py", line 187, in get_source
    raise TemplateNotFound(template)
jinja2.exceptions.TemplateNotFound: file.jinja.html

you may find the discussions online point that this issue must have something to do with the interaction of jinja2 with flask, with GAE, with Pyramid, or with SQL, and it may indeed be that your templates are not in a "template" folder, but this problem can arise from the interaction of jinja2 and the os module.

score 0 · Accepted Answer · answered Apr 01 '16 at 01:12

The culprit is changing the current directory by, for instance,

import os
os.chdir(someDir)

If templateEnv.get_template(...) is called past this point, jinja2 will look for the templates in the "current" dir, even if that has changed.

Since module os provides os.chdir but not os.pushdir/os.popdir, one has to either simulate the latter pair or avoid chdir altogether.

Cause of jinja2.exceptions.TemplateNotFound even when using just jinja2

1 Answers1