Python

Article
04/03/2023

Python is a scripting language that is popular for system automation and machine learning (ML). You can learn more about Python at python.org.

Using Python on x64 or x86

To install Python on Windows IoT Core:

Download the Python NuGet package, and then install the files using PowerShell.

$python_zip = "https://globalcdn.nuget.org/packages/python.3.7.4.nupkg"
if($env:PROCESSOR_ARCHITECTURE -ieq "x86") {
    $python_zip = "https://www.nuget.org/api/v2/package/pythonx86/3.7.4"
}
Invoke-WebRequest $python_zip -OutFile c:\data\python.zip
Expand-Archive C:\data\python.zip -DestinationPath c:\python_temp
move C:\python_temp\tools c:\python
rd C:\python_temp -Recurse -Force
del C:\data\python.zip

Add Python to the system path.

cmd /c 'setx PATH "%PATH%";c:\python;c:\python\scripts /M'
$env:Path += ";c:\python;c:\python\scripts"

Ensure that the current version of pip is installed
```
python -m pip install --upgrade pip
```

Using Python on Windows IoT Core ARM32

To get Python for Windows, you will need to build the binaries yourself.

Build Python for ARM32. The branch must be 3.8 or greater.

git clone https://github.com/python/cpython
cd cpython
git checkout 3.8
pcbuild\build.bat -p ARM --no-tkinter

Build Python .zip file for Windows IoT Core ARM32. The same version of Python must be used to run PC/layout. This step builds Python for x86 and uses it to build the .zip file(s). If you want the standard library tests in your .zip file add the --include-tests parameter.

REM Build Python for x86 to use for building the .zip file.
pcbuild\build.bat
pcbuild\win32\python.exe PC/layout -vv -s "." -b ".\PCBuild\arm32" -t ".\PCBuild\temp" --preset-iot --include-venv --zip ".\PCBuild\arm32\zip\python.zip"

net use P: \\[ip address]\c$ /user:administrator

copy .\PCBuild\arm32\zip\python.zip P:\data

Use PowerShell to extract the .zip file on the device and add Python to the system path.

Expand-Archive C:\data\python.zip -DestinationPath c:\python
cmd /c 'setx PATH "%PATH%";c:\python;c:\python\scripts /M'
$env:Path += ";c:\python;c:\python\scripts"

Verify that print('Hello World') works.

python -c "print('Hello World!');quit()"

Using Python on Windows IoT Core ARM64

To get Python for Windows, you will need to build the binaries yourself.

Clone Python for ARM32 and run get_externals. The branch must be 3.8 or greater.

git clone https://github.com/python/cpython
cd cpython
git checkout 3.8
pcbuild\get_externals.bat
cd ..

Clone and build libffi.

git clone https://github.com/libffi/libffi
set LIBFFI_SOURCE=%CD%\libffi

REM Visual Studio 2015 or greater with ARM64 tools installed is required to build Python
REM the location of VCVARSALL may differ on your machine
set VCVARSALL="C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvarsall.bat"

cd cpython
if exist c:\cygwin\bin\sh.exe (
    call pcbuild\prepare_libffi.bat -arm64
) else (
    call pcbuild\prepare_libffi.bat -arm64 --install-cygwin
)
if not exist externals\libffi\arm64\libffi-7.dll echo ERROR: libffi not built! & exit /b 1

Build Python for ARM64.

pcbuild\build.bat -p ARM64 --no-tkinter

Build Python .zip file for Windows IoT Core ARM64. The same version of Python must be used to run PC/layout. This step builds Python for x86 and uses it to build the .zip file(s). If you want the standard library tests in your .zip file add the --include-tests parameter.

REM Build Python for x86 to use for building the .zip file.
pcbuild\build.bat

REM Map drive to device and copy files using PC/layout
net use P: \\[ip address]\c$ /user:administrator
pcbuild\win32\python.exe PC/layout -vv -s "." -b ".\PCBuild\arm64" -t ".\PCBuild\temp" --preset-iot --include-venv --copy P:\python

Add Python to the system path.

setx PATH "%PATH%";c:\python;c:\python\scripts /M
set PATH=%PATH%;c:\python;c:\python\scripts

Verify that print('Hello World') works.

python -c "print('Hello World!');quit()"

Try out Azure IoT Hub Python SDKs v2 - PREVIEW

First install the SDK.
```
python -m pip install azure-iot-device
```
In the output for the pip install there may be errors: Download error on https://pypi.org/simple/pbr/. If you see this then, otherwise skip to Set up an IoT Hub and create a Device Identity:
Navigate to https://pypi.org/simple/pbr/ in your favorite browser. Inspect the web site's certificate and noticed that it issued by DigiCert.
Create a directory named c:\test.
Run certmgr.msc from a command prompt on a desktop Windows machine.
Navigate to Trusted Root Certification Authorities in the treeview. Expand the node and choose Certificates.
In the right pane find the DigiCert High Assurance EV Root, right-click and select All Tasks > Export. Note that there are multiple DigiCert certs and I identified this one by trying each one, one at a time.
In the dialog that pops up click Next.
Select DER encoded binary X.509 (.CER) (this should be the default) and click Next.
In the File name: edit box type c:\test\DigiCert High Assurance EV Root.cer
Click Next.
Click Finish.
Copy c:\test\DigiCert High Assurance EV Root.cer to the device by running the following command on your desktop machine:
```
net use X: \\host\c$ /user:host\administrator
md X:\test
copy "c:\test\GlobalSign Root CA.cer" X:\test
```

On the device, import the certificate into the root store using PowerShell.

certmgr -add "c:\test\DigiCert High Assurance EV Root.cer" -s root -r localMachine -c
certmgr -add "c:\test\GlobalSign Root CA.cer" -s root -r localMachine -c

Try to install the azure-iot-device again

python -m pip install azure-iot-device --no-color

In the output for the pip install there may be errors: Download error for https://files.pythonhosted.org/. If you don't see this, then skip to Set up an IoT Hub and create a Device Identity
Navigate to https://files.pythonhosted.org/ in your favorite browser. Inspect the web site's certificate and noticed that it issued by GlobalSign.
Repeat the steps to export the GlobalSign Root CA certificate from your desktop machine and import it on the device.
Try to install the azure-iot-device again.

Set up an IoT Hub and create a Device Identity

Install the Azure CLI (or use the Azure Cloud Shell) and use it to create an Azure IoT Hub.
```
az iot hub create --resource-group <your resource group> --name <your IoT Hub name>
```
- Note that this operation may take a few minutes.

Add the IoT Extension to the Azure CLI, and then register a device identity

az extension add --name azure-cli-iot-ext
az iot hub device-identity create --hub-name <your IoT Hub name> --device-id <your device id>

Retrieve your Device Connection String using the Azure CLI

az iot hub device-identity show-connection-string --device-id <your device id> --hub-name <your IoT Hub name>

It should be in the format:

HostName=<your IoT Hub name>.azure-devices.net;DeviceId=<your device id>;SharedAccessKey=<some value>

Send a simple telemetry message

Begin monitoring for telemetry on your IoT Hub using the Azure CLI

az iot hub monitor-events --hub-name <your IoT Hub name> --output table

On your device, set the Device Connection String as an environment variable called IOTHUB_DEVICE_CONNECTION_STRING.
```
REM NOTE: there are no quotes
set IOTHUB_DEVICE_CONNECTION_STRING=<your connection string here>
```

Copy simple_send_d2c_message.py and run it on the device.

cmd /c "if not exist c:\test md c:\test"
REM copy simple_send_d2c_message.py from https://github.com/Azure/azure-iot-sdk-python-preview/blob/master/azure-iot-device/samples/simple_send_d2c_message.py to c:\test on the device
python c:\test\simple_send_d2c_message.py

Using Python in an x64 docker container on Windows IoT Core

Download the newest docker, and install files.

Invoke-WebRequest https://master.dockerproject.org/windows/x86_64/docker.zip -OutFile c:\data\docker.zip
Expand-Archive c:\data\docker.zip -DestinationPath c:\data
move c:\data\docker\docker*exe c:\windows\system32
Remove-Item c:\data\docker -Recurse -Force
dockerd --register-service
net start docker

Create Dockerfile

# escape = `
FROM mcr.microsoft.com/windows/nanoserver:1809-amd64

# Get Python
ADD "https://globalcdn.nuget.org/packages/python.3.7.4.nupkg" .\temp\py.zip

COPY test test
COPY certmgr.exe c:\windows\system32

# need admin for setx and certmgr
USER ContainerAdministrator

# Extract Python
RUN tar -xf c:\temp\py.zip -C c:\temp && `
    move c:\temp\tools c:\ && `
    ren tools python && `
    RD c:\temp /s/q && `
    setx PATH "%PATH%";c:\python;c:\python\scripts /M

RUN dir c:\test\*.cer /s/b > c:\test\certs.txt && `
    for /f "delims==" %i in (c:\test\certs.txt) do certmgr -add "%i" -s root -r localMachine -c < c:\test\1.txt

USER ContainerUser

RUN python -m pip install --upgrade pip && `
    python -m pip install azure-iot-device

CMD cmd /k c:\test\start.cmd

Copy Dockerfile to c:\docker on device. Also copy any certificates to P:\docker\test. 1.txt is a file with the number 1 and a carriage return.

net use P: \\[device IP address]\c$ /user:administrator
md P:\docker\test
copy Dockerfile P:\docker
copy AppCertificates\*.cer P:\docker\test
copy 1.txt P:\docker\test

Connect to the device using SSH. Remote PowerShell will not work for an interactive docker session.
```
docker build --isolation==process . -t python
docker run --isolation==process python
```

Print hello world

python -c "print('Hello Python in Containers!')"

See Azure IoT SDK directions above to test cloud to device messages.