Azure WebApp Publish failed due to env not found error

Symptom

I tried to publish Flask app to Azure WebApp, but failed due to the error message below. Sadly, default Azure Flask template also failed to publish.

A virtual environment is required to deploy dependencies to Microsoft Azure Web Sites. Either add a virtual environment or add <SuppressWebSitesVirtualEnvError>true</SuppressWebSitesVirtualEnvError> to your project if you have no dependencies other than the Python standard library.

Reproduce Steps

1. git pull https://github.com/azureappserviceoss/FlaskAzure.git (azure default template)
2. In Visual Studio, New > Project > From Existing Python Code > select pulled folder.
3. In setup wizard, set as Flask app and Detect virtual environment.
4. It seems failed to detenct env directory. Project has Python27 (global default) as environment.
5. Right-click Python Environment and click Add Existing Virtual Environment.
6. Select env directory and it shows “We could not find a base interpreter at D:\Python27” error.
7. When right-click Python Environment and click Add/Remove Python Environments, the dialog shows env (unavailable) in environment list.

Questions

1. Why does VisualStudio point D:\Python27 in Step 6 and how can I fix it? I do not have D: drive and cannot find hard-coded line for that.
2. Where can I put <SuppressWebSitesVirtualEnvError>true</SuppressWebSitesVirtualEnvError> in web.config? I cannot find any documentation and example.

[huguesv]

Virtual environments have hard coded paths to the base python path, which can cause problems if you try to reuse them across machines like you are doing here.

I would recommend that you delete it and recreate it using PTVS. Since there’s a requirements.txt at the root, PTVS will check the “install packages” in the new virtual env dialog by default.

FYI SuppressWebSitesVirtualEnvError element is meant for the .pyproj file, not the web.config file.

[huguesv]

VS 2017 no longer requires a virtual env. Python is installed via site extension.