Validation of runtimes

[sriram-mv]

Description:

Runtime Validation for python works by invoking the python executable in the path to check if the local python runtime version matches the required runtime.

This relies on how the path is setup to find the appropriate version of python.

ISSUE

• When trying to build python2.7 lambda applications from within a sam installation housed in a python3.6 environment, one sees the following error message.

(venv) srirammv@localrainbow:~/sam-app$sam build
2018-11-26 13:40:16 Building resource 'HelloWorldFunction'
Build Failed
Error: python executable found in your path does not match runtime.
 Expected version: python2.7, Found version: python3.6.
 Possibly related: https://github.com/awslabs/aws-lambda-builders/issues/30

WORKAROUND:

Fixing this involves following steps:

• Moving up python executable of version python2.7 on the path

export PATH=/usr/bin:$PATH
python --version
2.7.10

(venv) srirammv@localrainbow::~/sam-app$sam build
2018-11-26 13:58:56 Building resource 'HelloWorldFunction'
2018-11-26 13:58:56 Running PythonPipBuilder:ResolveDependencies
2018-11-26 13:58:57 Running PythonPipBuilder:CopySource

Build Succeeded

Built Artifacts  : .aws-sam/build
Built Template   : .aws-sam/build/template.yaml

Commands you can use next
=========================
[*] Invoke Function: sam local invoke
[*] Package: sam package --s3-bucket <yourbucket>

PERMANENT FIX

A more permanent fix is in the works: #35

line in question: https://github.com/awslabs/aws-lambda-builders/blob/develop/aws_lambda_builders/validate.py#L17

RELATED GITHUB ISSUE

• "sam build" validation of runtimes aws-sam-cli#797

[visini]

@thesriram I have the reverse issue –  what do you suggest? Thanks!

2018-12-03 17:29:16 Found credentials in environment variables.
2018-12-03 17:29:16 Building resource 'HelloWorldFunction'
Error: python executable found in your path does not match runtime. 
 Expected version: python3.6, Found version: python2.7. 
 Possibly related: https://github.com/awslabs/aws-lambda-builders/issues/30
Build Failed

[AdamShechter9]

I also have the reverse issue

2018-12-03 21:28:06 Found credentials in environment variables.
2018-12-03 21:28:06 Building resource 'HelloWorldFunction'
Build Failed
Error: python executable found in your path does not match runtime.
Expected version: python3.6, Found version: python2.7.
Possibly related: #30

[visini]

Hi @AdamShechter9, I finally got this to work. I'm suspecting that like me, you're trying to run this on macOS. Make sure you’re running python 3.6. If you’ve installed python via brew like me, you may run into issues when deploying from PyCharm (see my tutorial here:
https://camillovisini.com/deploy-serverless-python-functions-aws-lambda-pycharm/).

Check your python version in Terminal:

python -V
# Python 2.7.1

If you’re output above is 3.6.x, you're fine. If not, you need to make sure the command python points to your python 3.6.x installation.

Add the following line to the top of /etc/paths by running sudo nano /etc/paths and saving it:

/usr/local/opt/python/libexec/bin

Then, confirm your Python version again in Terminal with:

python -V
# Python 3.6.5

You should be all set!

[sriram-mv]

What @visini says is correct. You need to have python3.6 installed, and also make sure its the first python in your path. Doing the following will let tell you, where the current python is coming from, and its rank in the path. You need to move the path where python3.6 is installed above the path from were your current python is.

which python
echo $PATH

[AdamShechter9]

thank you guys for the instruction.
I did have to redo my $PATH and put /usr/local/bin at the top.
I also had to redo the symbolic links in that folder, so python points to ../../../Library/Frameworks/Python.framework/Versions/3.6/bin/python3

[Marakai]

This will not work on systems that still require python to point to P2 for compatibility purposed, e.g. EL7 based Linuxes (RHEL, CentOS, Oracle, Scientific Linux).

Changing the link for python to python3 will break things.

The only work-around I can currently think of is something extremely ugly like:

ln -s /usr/bin/python3 /usr/local/bin/python
export PATH=/usr/local/bin:$PATH

[oxbits]

I had to force my link:
ln -fs /usr/local/bin/python3 /usr/local/bin/python

I had this error:
Expected version: python3.7, Found version: python2.7.

[marakere]

@visini - Thanks for the info. Unfortunately I have latest Python version, but still, sam complains about the version.

bash-3.2$ python -V
Python 3.7.0

bash-3.2$ sam build
2018-12-18 17:31:35 Found credentials in shared credentials file: ~/.aws/credentials
2018-12-18 17:31:36 Building resource 'HelloWorldFunction'
Build Failed
Error: python executable found in your path does not match runtime.
Expected version: python3.6, Found version: python2.7.
Possibly related: #30

Do you think below might be the problem? when I issue which python, it takes me to system provided python2.7

bash-3.2$ which python
/usr/bin/python

bash-3.2$ /usr/bin/python
Python 2.7.10 (default, Aug 17 2018, 19:45:58)
[GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.0.42)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

[rustyautopsy]

I have also run into this issue. I have been able to get a little further down the rabbit hole.

I am running a MAC and followed these commands from @visini post.

brew upgrade
brew update
brew tap aws/tap
brew install aws-sam-cli

NOTE: I was trying to use the pip installed version of aws-sam-cli and it didn't work.

I then created a new AWS Serverless Application in Pycharm, with a new Virtaulenv set to use python3.6.

When finished I tried to 'Deploy' the app via PyCharm and it failed with the Expected version: python3.6, Found version: python2.7. error.

So I then...

• dropped down to the cli in Pycharm with the virtualenv active sam build WORKS when run manually.
• jumping out of PyCharm and issued the same commands in iTerm, and those failed with the same Expected version: python3.6, Found version: python2.7. . When running this command the virtaulenv WAS NOT active.
• source venv/bin/activate and then sam build and SUCCESS.

My question now is when PyCharm issues the same sam build command is it respecting the virtaulenv the project is setup in?

[marakere]

Here is what I did, but I am not sure if this is an ideal way for every case.
instead of just going with sam build I added sam build --use-container
Notes for --use-container

[rustyautopsy]

At this time I can develop locally without the need to create custom PyCharm Run Configs so that's a win.

The deployment issues will need to get worked out, however, in our deployment pipelines, we would be running the native sam build/deploy commands anyway.

I suppose allowing devs to deploy alpha stacks from PyCharm would be cool for some smoke tests and some form of integration testing. So let's hope the deploy items get sorted soonish.

Cheers.