sam init errors with "No module named functools_lru_cache"

Description:

Steps to reproduce the issue:

$ sam init

Observed result:

[+] Initializing project structure...
Error: An error ocurred while generating this sam-app: Unable to load extension: No module named functools_lru_cache

Expected result: It just works!™ Additional environment details (Ex: Windows, Mac, Amazon Linux etc) macOS 10.13.5 Output of sam --version: SAM CLI, version 0.3.0 Optional Debug logs:

$ sam init --debug
2018-06-11 19:49:22 Init command
[+] Initializing project structure...
2018-06-11 19:49:22 Parameters dict created with input given
2018-06-11 19:49:22 {'no_input': False, 'output_dir': '.', 'template': '/Users/anon/Library/Python/2.7/lib/python/site-packages/samcli/local/init/templates/cookiecutter-aws-sam-hello-nodejs'}
2018-06-11 19:49:22 Parameters dict updated with project name as extra_context
2018-06-11 19:49:22 {'extra_context': {'project_name': u'sam-app', 'runtime': 'nodejs8.10'}, 'no_input': True, 'output_dir': '.', 'template': '/Users/anon/Library/Python/2.7/lib/python/site-packages/samcli/local/init/templates/cookiecutter-aws-sam-hello-nodejs'}
2018-06-11 19:49:22 Baking a new template with cookiecutter with all parameters
2018-06-11 19:49:22 context_file is /Users/anon/Library/Python/2.7/lib/python/site-packages/samcli/local/init/templates/cookiecutter-aws-sam-hello-nodejs/cookiecutter.json
2018-06-11 19:49:22 Context generated is {u'cookiecutter': OrderedDict([(u'project_name', u'sam-app'), (u'runtime', 'nodejs8.10')])}
Error: An error ocurred while generating this sam-app: Unable to load extension: No module named functools_lru_cache

[emilbryggare]

I had the same problem today. Resolved be uninstalling and installing backports.functools_lru_cache.

pip uninstall backports.functools_lru_cache pip install backports.functools_lru_cache

After this everything is working again.

[harprit]

The root cause seems that the functools_lru_cache related files were missing -

usr/lib/python2.7/dist-packages/backports$ ls
configparser  __init__.py  __init__.pyc

The above solution of uninstall/install didn’t work for me. matplotlib devs on Ubuntu were having same issue. Following their discussion, fixed the missing module issue with following command -

sudo apt-get install python-matplotlib

usr/lib/python2.7/dist-packages/backports$ ls
configparser functools_lru_cache.py  functools_lru_cache.pyc  __init__.py  __init__.pyc