Python Flask app on Azure broken after upgrading project from VS 2015 to 2017

We have a Python flask application running as an App Service in Azure. We recently upgraded our solutions to VS 2017. This changed some of the configuration files in the python project and now when we publish, we get:

HTTP Error 500.0 - Internal Server Error
 scriptProcessor could not be found in  application configuration

Detailed Error Information:
Module     FastCgiModule
Notification       ExecuteRequestHandler
Handler    PythonHandler
Error Code     0x80070585
Requested URL      http://OcvCluster-int__b155:80/handler.fcgi/

Physical Path      D:\home\site\wwwroot\handler.fcgi\
Logon Method       Anonymous
Logon User     Anonymous
Request Tracing Directory      D:\home\LogFiles

If I go back to an old (pre-upgrade) version I can publish from 2015. I can’t, however, open the latest master in 2015, so I am unable to publish changes we need in our service.

I have spent a full day going through articles like:
https://docs.microsoft.com/en-us/visualstudio/python/managing-python-on-azure-app-service https://docs.microsoft.com/en-us/visualstudio/python/publishing-to-azure

Trying many things with reg to updating my web.config.

Is there any information on what the upgrade path should be here? We are broken. Things that confuse me:

• Tutorials on publishing Flask apps to VS state that you need to install Python as an extension on the App Service. Is that new? We have not been doing that previously.
• We have a bunch of custom libraries in our env folder. In VS2015, those are uploaded as part of the publish process. When I publish from VS 2017 I don’t see that happening (though they are still there from previous publishes)
• Some forum posts have talked about having to point to the interpreter in the application.config. Our app does not have an application.config.

Here is my web.config (with the comments indicating where I have been experimenting).

                <?xml version="1.0"?>
            <!-- Generated web.config for Microsoft Azure. Remove this comment to prevent
                 modifications being overwritten when publishing the project.
            -->
            <configuration>
              <system.diagnostics>
                <trace>
                  <listeners>
                    <add type="Microsoft.WindowsAzure.Diagnostics.DiagnosticMonitorTraceListener, Microsoft.WindowsAzure.Diagnostics, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" name="AzureDiagnostics">
                      <filter type="" />
                    </add>
                  </listeners>
                </trace>
              </system.diagnostics>
              <appSettings>
                <add key="WSGI_ALT_VIRTUALENV_HANDLER" value="redacted.app" />
                <add key="WSGI_ALT_VIRTUALENV_ACTIVATE_THIS" value="D:\home\site\wwwroot\env3\Scripts\python.exe" />
                <add key="WSGI_HANDLER" value="ptvs_virtualenv_proxy.get_venv_handler()" />
                <!--add key="WSGI_HANDLER" value="redacted.app" />-->
                <add key="WSGI_LOG" value="D:\home\LogFiles\wfastcgi.log"/>
                <!--<add key="PYTHONPATH" value="%ROOTDIR%;%ROOTDIR%\redacted;%ROOTDIR%\redacted\Clusterer\" />-->
                <add key="PYTHONPATH" value="D:\home; D:\home\site;D:\home\site\redacted;D:\home\site\redacted\Clusterer\" />
              </appSettings>
              <system.web>
                <compilation debug="true" targetFramework="4.0" />
              </system.web>
              <system.webServer>
                <httpErrors errorMode="Detailed"></httpErrors>
                <modules runAllManagedModulesForAllRequests="true" />
                <handlers>
                  <!--<add name="Python FastCGI" path="handler.fcgi" verb="*" modules="FastCgiModule" scriptProcessor="%INTERPRETERPATH%|%WFASTCGIPATH%" resourceType="Unspecified" requireAccess="Script" />-->
                  <add name="PythonHandler" path="handler.fcgi" verb="*" modules="FastCgiModule" scriptProcessor="D:\home\python354x64\python.exe|D:\home\python354x64\wfastcgi.py" resourceType="Unspecified" requireAccess="Script"/>
                </handlers>
                <httpPlatform processPath="D:\home\python354x64\python.exe"
                              arguments="D:\home\site\wwwroot\runserver.py"
                              stdoutLogEnabled="true"
                              stdoutLogFile="D:\home\LogFiles\python.log"
                              startupTimeLimit="60"
                              processesPerApplication="16">
                  <environmentVariables>
                    <environmentVariable name="SERVER_PORT" value="%HTTP_PLATFORM_PORT%" />
                  </environmentVariables>
                </httpPlatform>
                <rewrite>
                  <rules>
                    <rule name="Static Files" stopProcessing="true">
                      <match url="^/static/.*" ignoreCase="true" />
                      <action type="Rewrite" url="^/redacted/static/.*" appendQueryString="true" />
                    </rule>
                    <rule name="Configure Python" stopProcessing="true">
                      <match url="(.*)" ignoreCase="false" />
                      <conditions>
                      </conditions>
                      <action type="Rewrite" url="handler.fcgi/{R:1}" appendQueryString="true" />
                    </rule>
                  </rules>
                </rewrite>
              </system.webServer>
            </configuration>

Thanks, ~john

As you found in the Managing Python on Azure App Service :

Although App Service by default has Python 2.7 and Python 3.4 installed in root folders on the server, you cannot customize or install packages in these environments.

So, Azure App Service recommands you rely on a site extension now.

As far as I know, we could list the version of python packages which program relies on in the requirements.txt file. Those packages will be downloaded into the env folder when the project is deployed to Azure.

However , this does not apply to site extensions now. You could install packages on KUDU console. Please refer to the steps I worked before.

Step 1 : Create azure web app and add Extensions(here is Python 3.6.1 x64)

Step 2 : Publish your flask project and add the web.config.

web.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <appSettings>
    <add key="WSGI_HANDLER" value="<Your Project Name>.app"/>
    <add key="PYTHONPATH" value="D:\home\site\wwwroot"/>
    <add key="WSGI_LOG" value="D:\home\LogFiles\wfastcgi.log"/>
  </appSettings>
  <system.webServer>
    <handlers>
      <add name="PythonHandler" path="*" verb="*" modules="FastCgiModule" scriptProcessor="D:\home\Python361x64\python.exe|D:\home\Python361x64\wfastcgi.py" resourceType="Unspecified" requireAccess="Script"/>
    </handlers>
  </system.webServer>
</configuration>

Step 3: Switch to the Kudu CMD and commands cd Python361x64 and touch get-pip.py and copy the content of the url https://bootstrap.pypa.io/get-pip.py into the get-pip.py via Edit button, then run python get-pip.py to install the pip tool.

Step 4 : Install pyodbc package or any packages you need via python -m pip install pyodbc

In addition, I notice that your PYTHONPATH configuration in the web.config does not include the root path of your app which is D:\home\site\wwwroot. The value for PYTHONPATH may be freely extended but must include the root of your app.

And you need to check if the Python Interpreter in the path which mapped to scriptProcessor exists.

Hope it helps you. Any concern ,please let me know.