Flask raises TemplateNotFound error even though template file exists

Question

I am trying to render the file home.html. The file exists in my project, but I keep getting jinja2.exceptions.TemplateNotFound: home.html when I t

Answer 1

If you run your code from an installed package, make sure template files are present in directory /lib/site-packages/your-package/templates.

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Some details:

In my case I was trying to run examples of project flask_simple_ui and jinja would always say

jinja2.exceptions.TemplateNotFound: form.html

The trick was that sample program would import installed package flask_simple_ui. And ninja being used from inside that package is using as root directory for lookup the package path, in my case ...python/lib/site-packages/flask_simple_ui, instead of os.getcwd() as one would expect.

To my bad luck, setup.py has a bug and doesn't copy any html files, including the missing form.html. Once I fixed setup.py, the problem with TemplateNotFound vanished.

I hope it helps someone.