Difference between revisions of "DESK-MX6UL-AN-0004: Using Python for Embedded applications"
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In case of some troubles (which can happens using <code>easy_install</code> or <code>pip</code>), other packages can be directly installed using <code>dnf</code> from the already built ''rpm'' packages built with Yocto: | In case of some troubles (which can happens using <code>easy_install</code> or <code>pip</code>), other packages can be directly installed using <code>dnf</code> from the already built ''rpm'' packages built with Yocto: | ||
| − | For example, for installing | + | For example, for installing ''ujson''' it is possible to use <code>dnf install <rpm-package></code>: |
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root@desk-mx6ul-axelulite:~# dnf install python3-ujson | root@desk-mx6ul-axelulite:~# dnf install python3-ujson | ||
Last metadata expiration check: 1:31:56 ago on Wed Oct 6 08:39:56 2021. | Last metadata expiration check: 1:31:56 ago on Wed Oct 6 08:39:56 2021. | ||
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root@desk-mx6ul-axelulite:~# | root@desk-mx6ul-axelulite:~# | ||
</pre> | </pre> | ||
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== import packages== | == import packages== | ||
Revision as of 10:59, 7 October 2021
| HOME | SOMs | SBCs | ToloMEO Embedded Assistant |  GET A QUOTE
|
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| Roadmap | IoT Services | ML/AI services | Embedded Design Services |
 This application note has been validated using the kit version in the History table. |
Contents
History[edit | edit source]
| Version | Date | Development Kit version |
|---|---|---|
| 1.0.0 | Oct 2021 | DESK-MX6UL-L 1.0.1 |
Introduction[edit | edit source]
As found on Python official website, Python is a programming language that lets you work more quickly and integrate your systems more effectively and also Python can be easy to pick up whether you're a first-time programmer or you're experienced with other languages.
These sentences got a real confirmation if you have a look at the IEEE Top Programming Languages 2021 ranking. As you can see in the following picture Python reached the Top of the ranking even more than the native C language used since the beginning in Embedded systems programming:
As reported in this article The C/C++ programming languages dominate embedded systems programming, though they have a number of disadvantages. Python, on the other hand, has many strengths that make it a great language for embedded systems.
This application note provides some examples of software packages installation that can be used for adding python3 libraries to the SBC Lynx platform.
Python on DESK[edit | edit source]
python and python3 applications are already present on DESK-MX6UL-L dave-image-devel root file system.
Moreover, a huge list of python packages can be installed in the target using the DNF package manager: the DESK-MX6UL-AN-0003 shows how to install rpm packages in the target from the DAVE's Yocto repository server.
Installing python packages[edit | edit source]
First of all check for the default installed python/pip version in the DESK-MX6UL root file system:
root@desk-mx6ul-axelulite:~# python3 --version Python 3.5.5 root@desk-mx6ul-axelulite:~# pip --version pip 9.0.3 from /usr/lib/python2.7/site-packages (python 2.7) root@desk-mx6ul-axelulite:~#
This shows that pip3 is not present in the root file system and should be installed: the simpler way is using python3 itself and the provided python script get-pip.py for version 3.5:
root@desk-mx6ul-axelulite:~# python3 get-pip.py
DEPRECATION: Python 3.5 reached the end of its life on September 13th, 2020. Please upgrade your Python as Python 3.5 is no longer maintained. pip 21.0 will drop support for Python 3.5 in January 2021. pip 21.0 will remove support for this functionality.
Collecting pip<21.0
Downloading pip-20.3.4-py2.py3-none-any.whl (1.5 MB)
|################################| 1.5 MB 176 kB/s
Collecting wheel
Downloading wheel-0.37.0-py2.py3-none-any.whl (35 kB)
Installing collected packages: wheel, pip
Successfully installed pip-20.3.4 wheel-0.37.0
root@desk-mx6ul-axelulite:~# pip
pip pip2 pip2.7 pip3 pip3.5
root@desk-mx6ul-axelulite:~#
After the installation, pip3 is the latest version available for Python3 3.5.5:
root@desk-mx6ul-axelulite:~# pip3 --version pip 20.3.4 from /usr/lib/python3.5/site-packages/pip (python 3.5) root@desk-mx6ul-axelulite:~# easy3_install --version setuptools 39.0.0 from /usr/lib/python3.5/site-packages (Python 3.5) root@desk-mx6ul-axelulite:~#
easy install[edit | edit source]
Even if easy_install tool has been deprecated, it is a useful tool still present in the typical python distributions.
For the purposes of this Application Note, the tool has been used to install some python packages typically used in an Industrial Gateway equipment
In this example, the following packages are installed using easy3_install (easy_install version for python3): pyserial and pymodbus (for bus communications), requests (HTTP library), schema, ssdp:
root@desk-mx6ul-axelulite:~# easy3_install pyserial Searching for pyserial Reading https://pypi.python.org/simple/pyserial/ Downloading https://files.pythonhosted.org/packages/07/bc/587a445451b253b285629263eb51c2d8e9bcea4fc97826266d186f96f558/pyserial-3.5-py2.py3-none-any.whl#sha256=c4451db6ba391ca6ca299fb3ec7bae67a5c55dde170964c7a14ceefec02f2cf0 Best match: pyserial 3.5 Processing pyserial-3.5-py2.py3-none-any.whl Installing pyserial-3.5-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages writing requirements to /usr/lib/python3.5/site-packages/pyserial-3.5-py3.5.egg/EGG-INFO/requires.txt Adding pyserial 3.5 to easy-install.pth file Installing pyserial-miniterm script to /usr/bin Installing pyserial-ports script to /usr/bin Installed /usr/lib/python3.5/site-packages/pyserial-3.5-py3.5.egg Processing dependencies for pyserial Finished processing dependencies for pyserial root@desk-mx6ul-axelulite:~# easy3_install pymodbus Searching for pymodbus Reading https://pypi.python.org/simple/pymodbus/ Downloading https://files.pythonhosted.org/packages/57/21/6c9b1cade55161444450bdde6e953edb819d984beafee8d4baefa4f0310c/pymodbus-2.5.3rc1-py2.py3-none-any.whl#sha256=e8cbf3594a8dd0f71c287e24d8365e69836c8d22cac5ab288110638fd2b9fda6 Best match: pymodbus 2.5.3rc1 Processing pymodbus-2.5.3rc1-py2.py3-none-any.whl Installing pymodbus-2.5.3rc1-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages writing requirements to /usr/lib/python3.5/site-packages/pymodbus-2.5.3rc1-py3.5.egg/EGG-INFO/requires.txt Adding pymodbus 2.5.3rc1 to easy-install.pth file Installing pymodbus.console script to /usr/bin Installing pymodbus.server script to /usr/bin Installed /usr/lib/python3.5/site-packages/pymodbus-2.5.3rc1-py3.5.egg Processing dependencies for pymodbus Searching for six>=1.15.0 Reading https://pypi.python.org/simple/six/ Downloading https://files.pythonhosted.org/packages/d9/5a/e7c31adbe875f2abbb91bd84cf2dc52d792b5a01506781dbcf25c91daf11/six-1.16.0-py2.py3-none-any.whl#sha256=8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254 Best match: six 1.16.0 Processing six-1.16.0-py2.py3-none-any.whl Installing six-1.16.0-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages Adding six 1.16.0 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/six-1.16.0-py3.5.egg Finished processing dependencies for pymodbus root@desk-mx6ul-axelulite:~# easy3_install requests Searching for requests Reading https://pypi.python.org/simple/requests/ Downloading https://files.pythonhosted.org/packages/92/96/144f70b972a9c0eabbd4391ef93ccd49d0f2747f4f6a2a2738e99e5adc65/requests-2.26.0-py2.py3-none-any.whl#sha256=6c1246513ecd5ecd4528a0906f910e8f0f9c6b8ec72030dc9fd154dc1a6efd24 Best match: requests 2.26.0 Processing requests-2.26.0-py2.py3-none-any.whl Installing requests-2.26.0-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages writing requirements to /usr/lib/python3.5/site-packages/requests-2.26.0-py3.5.egg/EGG-INFO/requires.txt Adding requests 2.26.0 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/requests-2.26.0-py3.5.egg Processing dependencies for requests Searching for urllib3<1.27,>=1.21.1 Reading https://pypi.python.org/simple/urllib3/ Downloading https://files.pythonhosted.org/packages/af/f4/524415c0744552cce7d8bf3669af78e8a069514405ea4fcbd0cc44733744/urllib3-1.26.7-py2.py3-none-any.whl#sha256=c4fdf4019605b6e5423637e01bc9fe4daef873709a7973e195ceba0a62bbc844 Best match: urllib3 1.26.7 Processing urllib3-1.26.7-py2.py3-none-any.whl Installing urllib3-1.26.7-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages writing requirements to /usr/lib/python3.5/site-packages/urllib3-1.26.7-py3.5.egg/EGG-INFO/requires.txt Adding urllib3 1.26.7 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/urllib3-1.26.7-py3.5.egg Searching for idna<4,>=2.5 Reading https://pypi.python.org/simple/idna/ Downloading https://files.pythonhosted.org/packages/d7/77/ff688d1504cdc4db2a938e2b7b9adee5dd52e34efbd2431051efc9984de9/idna-3.2-py3-none-any.whl#sha256=14475042e284991034cb48e06f6851428fb14c4dc953acd9be9a5e95c7b6dd7a Best match: idna 3.2 Processing idna-3.2-py3-none-any.whl Installing idna-3.2-py3-none-any.whl to /usr/lib/python3.5/site-packages Adding idna 3.2 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/idna-3.2-py3.5.egg Searching for charset-normalizer~=2.0.0 Reading https://pypi.python.org/simple/charset-normalizer/ Downloading https://files.pythonhosted.org/packages/3f/65/69e6754102dcd018a0f29e4db673372eb323ee504431125ab6c9109cb21c/charset_normalizer-2.0.6-py3-none-any.whl#sha256=5d209c0a931f215cee683b6445e2d77677e7e75e159f78def0db09d68fafcaa6 Best match: charset-normalizer 2.0.6 Processing charset_normalizer-2.0.6-py3-none-any.whl Installing charset_normalizer-2.0.6-py3-none-any.whl to /usr/lib/python3.5/site-packages writing requirements to /usr/lib/python3.5/site-packages/charset_normalizer-2.0.6-py3.5.egg/EGG-INFO/requires.txt Adding charset-normalizer 2.0.6 to easy-install.pth file Installing normalizer script to /usr/bin Installed /usr/lib/python3.5/site-packages/charset_normalizer-2.0.6-py3.5.egg Searching for certifi>=2017.4.17 Reading https://pypi.python.org/simple/certifi/ Downloading https://files.pythonhosted.org/packages/05/1b/0a0dece0e8aa492a6ec9e4ad2fe366b511558cdc73fd3abc82ba7348e875/certifi-2021.5.30-py2.py3-none-any.whl#sha256=50b1e4f8446b06f41be7dd6338db18e0990601dce795c2b1686458aa7e8fa7d8 Best match: certifi 2021.5.30 Processing certifi-2021.5.30-py2.py3-none-any.whl Installing certifi-2021.5.30-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages Adding certifi 2021.5.30 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/certifi-2021.5.30-py3.5.egg Finished processing dependencies for requests root@desk-mx6ul-axelulite:~# easy3_install schema Searching for schema Reading https://pypi.python.org/simple/schema/ Downloading https://files.pythonhosted.org/packages/c7/64/497632c9dc3c1bc94a92d9cafdc5cbd21d011bb651952765195739129a49/schema-0.7.4-py2.py3-none-any.whl#sha256=cf97e4cd27e203ab6bb35968532de1ed8991bce542a646f0ff1d643629a4945d Best match: schema 0.7.4 Processing schema-0.7.4-py2.py3-none-any.whl Installing schema-0.7.4-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages writing requirements to /usr/lib/python3.5/site-packages/schema-0.7.4-py3.5.egg/EGG-INFO/requires.txt Adding schema 0.7.4 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/schema-0.7.4-py3.5.egg Processing dependencies for schema Searching for contextlib2>=0.5.5 Reading https://pypi.python.org/simple/contextlib2/ Downloading https://files.pythonhosted.org/packages/76/56/6d6872f79d14c0cb02f1646cbb4592eef935857c0951a105874b7b62a0c3/contextlib2-21.6.0-py2.py3-none-any.whl#sha256=3fbdb64466afd23abaf6c977627b75b6139a5a3e8ce38405c5b413aed7a0471f Best match: contextlib2 21.6.0 Processing contextlib2-21.6.0-py2.py3-none-any.whl Installing contextlib2-21.6.0-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages Adding contextlib2 21.6.0 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/contextlib2-21.6.0-py3.5.egg Finished processing dependencies for schema root@desk-mx6ul-axelulite:~# easy3_install ssdp Searching for ssdp Reading https://pypi.python.org/simple/ssdp/ Downloading https://files.pythonhosted.org/packages/1d/04/d761ea63c8cb9e0e8a37cc63df9ec39c8c6a0f77363d131035b694758a5d/ssdp-1.1.0-py2.py3-none-any.whl#sha256=dc91a844e54ba6b1a2f3be4d9a52302027f71719c5eb2c0e6fbd77e67e7343ad Best match: ssdp 1.1.0 Processing ssdp-1.1.0-py2.py3-none-any.whl Installing ssdp-1.1.0-py2.py3-none-any.whl to /usr/lib/python3.5/site-packages Adding ssdp 1.1.0 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/ssdp-1.1.0-py3.5.egg Processing dependencies for ssdp Finished processing dependencies for ssdp root@desk-mx6ul-axelulite:~#
Then, add some useful IP packages like nmap or scapy (network packet manipulation):
root@desk-mx6ul-axelulite:~# easy3_install nmap Searching for nmap Reading https://pypi.python.org/simple/nmap/ Downloading https://files.pythonhosted.org/packages/f8/6f/6813025bd575ebc771189afaab7c405fdf3f1febaa197525d5aa6fd88ac5/nmap-0.0.1-py3-none-any.whl#sha256=158de16af02043e1a2015662ad1710dfb46dadd2bea8e9d90ba16b78b6650098 Best match: nmap 0.0.1 Processing nmap-0.0.1-py3-none-any.whl Installing nmap-0.0.1-py3-none-any.whl to /usr/lib/python3.5/site-packages Adding nmap 0.0.1 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/nmap-0.0.1-py3.5.egg Processing dependencies for nmap Finished processing dependencies for nmap root@desk-mx6ul-axelulite:~# easy3_install scapy Searching for scapy Reading https://pypi.python.org/simple/scapy/ Downloading https://files.pythonhosted.org/packages/85/47/c919432ca258f354bb2c1e645623f891603f185bfc7563d4a21f6432e7ed/scapy-2.4.5.tar.gz#sha256=bc707e3604784496b6665a9e5b2a69c36cc9fb032af4864b29051531b24c8593 Best match: scapy 2.4.5 Processing scapy-2.4.5.tar.gz Writing /tmp/easy_install-vsqq0ans/scapy-2.4.5/setup.cfg Running scapy-2.4.5/setup.py -q bdist_egg --dist-dir /tmp/easy_install-vsqq0ans/scapy-2.4.5/egg-dist-tmp-nauxdhas /usr/lib/python3.5/distutils/dist.py:261: UserWarning: Unknown distribution option: 'long_description_content_type' warnings.warn(msg) creating /usr/lib/python3.5/site-packages/scapy-2.4.5-py3.5.egg Extracting scapy-2.4.5-py3.5.egg to /usr/lib/python3.5/site-packages Adding scapy 2.4.5 to easy-install.pth file Installing scapy script to /usr/bin Installing UTscapy script to /usr/bin Installed /usr/lib/python3.5/site-packages/scapy-2.4.5-py3.5.egg Processing dependencies for scapy Finished processing dependencies for scapy root@desk-mx6ul-axelulite:~#
On top of that, some web packages are very useful for creating web application and remotely control/get information from the gateway: bottle (lightweight WSGI micro web-framework), fastapi (high-performance web framework). For this task we used pip3:
root@desk-mx6ul-axelulite:~# pip3 install bottle
DEPRECATION: Python 3.5 reached the end of its life on September 13th, 2020. Please upgrade your Python as Python 3.5 is no longer maintained. pip 21.0 will drop support for Python 3.5 in January 2021. pip 21.0 will remove support for this functionality.
Collecting bottle
Downloading bottle-0.12.19-py3-none-any.whl (89 kB)
|################################| 89 kB 486 kB/s
Installing collected packages: bottle
Successfully installed bottle-0.12.19
root@desk-mx6ul-axelulite:~# pip3 install flask
DEPRECATION: Python 3.5 reached the end of its life on September 13th, 2020. Please upgrade your Python as Python 3.5 is no longer maintained. pip 21.0 will drop support for Python 3.5 in January 2021. pip 21.0 will remove support for this functionality.
Collecting flask
Downloading Flask-1.1.4-py2.py3-none-any.whl (94 kB)
|################################| 94 kB 299 kB/s
Collecting click<8.0,>=5.1
Downloading click-7.1.2-py2.py3-none-any.whl (82 kB)
|################################| 82 kB 75 kB/s
Collecting Jinja2<3.0,>=2.10.1
Downloading Jinja2-2.11.3-py2.py3-none-any.whl (125 kB)
|################################| 125 kB 228 kB/s
Collecting itsdangerous<2.0,>=0.24
Downloading itsdangerous-1.1.0-py2.py3-none-any.whl (16 kB)
Collecting Werkzeug<2.0,>=0.15
Downloading Werkzeug-1.0.1-py2.py3-none-any.whl (298 kB)
|################################| 298 kB 141 kB/s
Collecting MarkupSafe>=0.23
Downloading MarkupSafe-1.1.1.tar.gz (19 kB)
Building wheels for collected packages: MarkupSafe
Building wheel for MarkupSafe (setup.py) ... done
Created wheel for MarkupSafe: filename=MarkupSafe-1.1.1-cp35-cp35m-linux_armv7l.whl size=30216 sha256=8625a9a35d280496da7b267207b70a9484b699e18f17bb869ca8bfa8ea4dfb25
Stored in directory: /home/root/.cache/pip/wheels/18/c6/76/e7b4c7aeea1fc00134bfddf7ebadb0d91afda4c958b5bd4032
Successfully built MarkupSafe
Installing collected packages: MarkupSafe, Werkzeug, Jinja2, itsdangerous, click, flask
Successfully installed Jinja2-2.11.3 MarkupSafe-1.1.1 Werkzeug-1.0.1 click-7.1.2 flask-1.1.4 itsdangerous-1.1.0
root@desk-mx6ul-axelulite:~#
and finally an MQTT client like Eclipse paho MQTT is installed too:
root@desk-mx6ul-axelulite:~# easy3_install paho-mqtt Searching for paho-mqtt Reading https://pypi.python.org/simple/paho-mqtt/ Downloading https://files.pythonhosted.org/packages/32/d3/6dcb8fd14746fcde6a556f932b5de8bea8fedcb85b3a092e0e986372c0e7/paho-mqtt-1.5.1.tar.gz#sha256=9feb068e822be7b3a116324e01fb6028eb1d66412bf98595ae72698965cb1cae Best match: paho-mqtt 1.5.1 Processing paho-mqtt-1.5.1.tar.gz Writing /tmp/easy_install-vkarrpqi/paho-mqtt-1.5.1/setup.cfg Running paho-mqtt-1.5.1/setup.py -q bdist_egg --dist-dir /tmp/easy_install-vkarrpqi/paho-mqtt-1.5.1/egg-dist-tmp-tt8lku70 creating /usr/lib/python3.5/site-packages/paho_mqtt-1.5.1-py3.5.egg Extracting paho_mqtt-1.5.1-py3.5.egg to /usr/lib/python3.5/site-packages Adding paho-mqtt 1.5.1 to easy-install.pth file Installed /usr/lib/python3.5/site-packages/paho_mqtt-1.5.1-py3.5.egg Processing dependencies for paho-mqtt Finished processing dependencies for paho-mqtt root@desk-mx6ul-axelulite:~#
DNF[edit | edit source]
In case of some troubles (which can happens using easy_install or pip), other packages can be directly installed using dnf from the already built rpm packages built with Yocto:
For example, for installing ujson' it is possible to use dnf install <rpm-package>:
root@desk-mx6ul-axelulite:~# dnf install python3-ujson Last metadata expiration check: 1:31:56 ago on Wed Oct 6 08:39:56 2021. Dependencies resolved. ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: python3-ujson cortexa7hf_neon 1.35-r0 cortexa7hf 24 k Transaction Summary ================================================================================ Install 1 Package Total download size: 24 k Installed size: 59 k Is this ok [y/N]: y Downloading Packages: python3-ujson-1.35-r0.cortexa7hf_neon.rpm 22 kB/s | 24 kB 00:01 -------------------------------------------------------------------------------- Total 21 kB/s | 24 kB 00:01 Running transaction check Transaction check succeeded. Running transaction test Transaction test succeeded. Running transaction Preparing : 1/1 Installing : python3-ujson-1.35-r0.cortexa7hf_neon 1/1 Verifying : python3-ujson-1.35-r0.cortexa7hf_neon 1/1 Installed: python3-ujson.cortexa7hf_neon 1.35-r0 Complete! root@desk-mx6ul-axelulite:~#
import packages[edit | edit source]
Finally, after the installation steps, it is possible to import the packages:
root@desk-mx6ul-axelulite:~# python3 Python 3.5.5 (default, Jul 16 2020, 16:11:13) [GCC 7.3.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import sys >>> import os >>> import time >>> import supervisor >>> import ssl >>> import nmap >>> import scapy >>> import serial >>> import pymodbus >>> import schema >>> import ssdp >>> import requests >>> import flask >>> import bottle >>> import ujson >>> import paho >>>
