So you are trying to program the Raspberry expansion PINS in Python, for example for this 3D LED Christmas Tree, and you’re getting the error:
GPIO.setup(self.number, GPIO.IN, self.GPIO_PULL_UPS[self._pull]) RuntimeError: Not running on a RPi!
I’m running this on Ubuntu 20.04LTS with a Raspberry 4.
The first thing:
Make sure you have an official Raspberry Pi charger.
Or at least, make sure your USB charger provides enough intensity to power the Raspberry and the LEDs.
The LED power comes from the motherboard and if Raspberry Pi has not enough energy this is not going to work.
My colleague Michela had her tree not working because of the charger was not able to provide enough energy. When she ordered a new charger, it worked like a charm.
Install the base Software
In order to communicate with General Purpose Input Output ports (GPIO) you need to install this Software:
I saw many people stuck, in the forums, because of that.
To work with the LEDs you need to run the samples as root.
Some code examples
To provide a bit of “the whole package” here are some simple examples.
Turn to red the LED’s one by one
from tree import RGBXmasTree
from time import sleep
o_tree = RGBXmasTree()
for o_pixel in o_tree:
o_pixel.color = (1, 0, 0)
sleep(0.1)
Turn to a different color, sleep, and again
from tree import RGBXmasTree
from time import sleep
o_tree = RGBXmasTree()
a_t_colors = [(1, 0, 0), (0, 1, 0), (0, 0, 1)]
for t_color in a_t_colors:
o_tree.color = t_color
sleep(1)
Turn off the lights
from tree import RGBXmasTree
o_tree = RGBXmasTree()
o_tree.color = (0, 0, 0)
I have updated CTOP.py so now it detects if is running in a Google GCP instance.
So the list of instances/type of virtualization detected is:
Amazon AWS
Google GCP
OpenStack
VirtualBox
Docker containers
LXC
I’m working in detecting Raspberry Pi, models running CTOP, and in enabling the plugins system so anybody can easily expand the functionality of ctop.py.
v.0.7.8 Commented annotations and type hinting, to make CTOP compatible with Python 3.5.0. Added Available RAM. Added Google GCP detection. Inform if it doesn't have permissions to decode DMI. Print the userId (numeric) and the User (string), like: 1000 carles or 0 root. Logic for swappiness <= 10 Ok, >10 and <= 30 warning, >30 red (alert). Reduced digits for swap to 2, to avoid confusions.
I have updated my book Python 3 Combat Guide, with another full cycle, step by step, to convert an ugly script that escapes to shell to a nice OOP code with Unit Testing, step by step.
I have updated my book ZFS for Ubuntu 20.04 LTS, adding how to create a pool and Datasets for home, sharing NFS for the Media Player.
If you like Star Wars and the Mandalorian, you may laugh has much as I did with this video:
As you see I’m writing more articles about Windows, Mac Os X, and proprietary Software. Some of my colleagues work in companies and use proprietary Software, so I’ll be writing more articles about those ecosystems. I spend more time now with colleagues working on all kind of projects, and with students that have other problems too, so I help them. However my main focus is Open Source, Architecture, Scaling, programming in Python and Java.
Time ago there was a web page that was rendered in blank for certain group of users.
The errors were coming from an Oracle instance. One SysAdmin restarted the instance, but the errors continued.
Often there are problems due to having two different worlds: Development and Production/Operations.
What works in Development, or even in Docker, may not work at Scale in Production.
That query that works with 100,000 products, may not work with 10,000,000.
I have programmed a lot for web, so when I saw a blank page I knew it was an internal error as the headers sent by the Web Server indicated 500. DBAs were seeing elevated number of errors in one of the Servers.
So I went straight to the Oracle’s logs for that Servers.
Just before this error, there was an error with a Query, and the PID matched, so it seemed cleared to me that the query was causing the crash at Oracle level.
Basically in our case, the query that was launched by the BackEnd was using more memory than allowed, which caused Oracle to kill it.
That is a tunnable that you can modify introduced in Oracle 10g.
You can see the current values first:
SQL> select
2 nam.ksppinm NAME,
3 nam.ksppdesc DESCRIPTION,
4 val.KSPPSTVL
5 from
6 x$ksppi nam,
7 x$ksppsv val
8 where nam.indx = val.indx and nam.ksppinm like '%kgl_large_heap_%_threshold%';
NAME | DESCRIPTION | KSPPSTVL
=============================================================================================
_kgl_large_heap_warning_threshold | maximum heap size before KGL | 4194304
writes warnings to the alert log
---------------------------------------------------------------------------------------------
_kgl_large_heap_assert_threshold | maximum heap size before KGL | 4194304
raises an internal error
So, _kgl_large_heap_warning_threshold is the maximum heap before getting a warning, and _kgl_large_heap_assert_threshold is the maximum heap before getting the error.
Depending in your case the solution can be either:
Breaking your query in several to reduce the memory used
Use paginating or LIMIT
Set a bigger value for those tunnables.
It will work setting 0 for these to variables, although I don’t recommend it to you, as you want your Server to kill queries that are taking more memory than you want.
To increase the value of , you have to update it. Please note it is in bytes, so for 32MB is 32 * 1024 * 1024, so 33,554,432, and using spfile:
SQL> alter system set "_kgl_large_heap_warning_threshold"=33554432scope=spfile ;
SQL> shutdown immediate
SQL> startup
SQL> show parameter _kgl_large_heap_warning_threshold
NAME TYPE VALUE
==================================|=========|===============
_kgl_large_heap_warning_threshold | integer | 33554432
This is a trick I share, as I see many students having problems with this.
Assuming that your Kali distribution is recent (Linux Kernel bigger than Kernel 5.3), the most typical problem student have is that laptops xps from Dell and other brands have a combination of keys to enable or disable the Wifi.
On the Dell xps is on the key PrtScr, so if your Wifi is disabled, you can enable it in Kali Linux press:
CTRL + ALT + Fn + PrtScr
As you can see in the PrtScr the is an icon of Wifi Signal.
The Fn key is on the bottom left, next to Ctrl.
This is a very simple to fix problem, but many people suffer this problem and go crazy trying to update drivers or even having to use an external USB dongle.
I reproduced your case in a VM and paste here step by step. :)
Note: First of all, please do a backup of your data. I added an empty new disk, so ZFS had no doubt what was the master drive. Although you should have no problem as the first drive already forms part of the pool, a backup is recommended.
Quick answer: You need the zpool attach command.
Basically:
sudo zpool attach hdd0 existinghdd blankhdd
After, do:
zpool status
And you will see that a mirror has been created. Your data on the already existing drive will be keep, and will be replicated to the new one (Resilvered).
As ZFS only copys the actual information this process will take more or less depending on the amount of Data.
In my VM 300 GB were replicated in 3 seconds, while my experience with SAS and SATA drives, I was Resilvering 10 TB in less than 24 hours (for that I was using drives from 10TB to 14TB SAS) .
Now the long answer with everything I did in my Virtual Box VM:
lsblk --scsi
identify the two empty drives by:
ls /dev/disk/by-id/
Select one of them and create a pool like your: sudo zpool create hdd0 id_of_mydrive
See that pool /hdd0 has been created and mounted on root.
sudo zpool statussudo zpool listsudo ls -al /hdd0
Fill with some random data (or better copy files there) to generate a drive like data like you. I generated from random:
pool: hdd0
state: ONLINE
scan: resilvered 301M in 0 days 00:00:03 with 0 errors…
NAME STATE READ WRITE CKSUM hdd0 mirror-0 ata-VBOX_HARDDISK_VBa8... ONLINE 0 0 0 ata-VBOX_HARDDISK_VB8c... ONLINE 0 0 0
errors: No known data errors
I verified the checksums.
zpool list will return as well 99GB of space available, as two drives of 100GB are being used in mirror.
So as kaulex mentioned the format is: zpool attach
Where device is your previous vdev with data (the single hard drive with Data in the ZFS pool named ‘hdd0’).
As I did you want to use the Id of the device and not the name, so you will use the identifier in /dev/disk/by-id/ and not sdb, sdc… (Please note, adding /dev/ is not necessary). The reason to do not use device names like sdb, sdc, sdea, etc… is that those names may change why live is running or between reboots. The id never changes. In real systems, not Virtual Box, they may start by wwn or ata.
I’ve been helping to troubleshoot the reason one Commodity Server (with no iDrac/Ilo ipmi) is powering off randomly. One of the hypothesis is the temperature.
This is a very simple script that will print the temperature of the HDDs and the CPU and keep to a log file.
First you need to install hddtemp and lm-sensors:
sudo apt install hddtemp lm-sensors
Then this is the one line script, that you should execute as root:
while [ true ]; do date | tee -a /var/log/hddtemp.log; hddtemp /dev/sda /dev/sdb /dev/sdc /dev/sdd | tee -a /var/log/hddtemp.log; date | tee -a /var/log/cputemp.log; sensors | tee -a /var/log/cputemp.log; sleep 2; done
Feel free to change sleep 2 for the number of seconds you want to wait, like sleep 10.
Press CTRL + C to interrupt the script at any time.
You can execute this inside a screen session and leave it running in Background.
Note that I use tee command, so the output is print to the screen and to the log file.
This explains how to solve a problem if you logged in to the domain, via your computer, as a regular user, and then you need to run Active Directory with Administrator privileges as another user.
You know I love Linux. I was compiling my own Kernels back in 1995, when it took more than 24 hours in a 386, and working on the first ISPs in Barcelona managing the Linux Systems.
For my computers I prefer Linux, no doubt about it, but many multinationals I worked for have Windows option only for the Laptops and Desktops.
During years I had to deal with sending files to Linux or Unix (HP UX, Sun Solaris…) to process them and getting back the result. Some sort of ETL and Map Reduce in the prehistory of personal computers, taking in count aspects like Networks speeds too, available space, splitting files for processing.
When I was working as Senior Project Manager in Winterthur Insurance, now Axa, I had to run a lot of ETL (Extract Transform Load) for considerably big files, or when I was project manager and later head of department in Volkswagen gedas or later helping Start ups like Privalia. I can tell you that Windows didn’t like you to open editors to work with 1GB text or CSV file, and doesn’t like it, even if your computer has 16GB of Memory, and even if they do the simplicity of Bash scripts and using pipes, grep, awk… is so powerful that is very convenient to have those files processed using Linux.
And honestly is a pain to send back and forth files to a UNIX System just for Data Crunch. And a VM will be slow and use memory, and you have enable some sort of sharing with it so it can access the Data. Not to talk if you need to split the data files in blocks to be processed in parallel by several computers.
There are many solutions, like using Virtual Machines, Docker, external Servers, etc…
WSL allows you to run Linux command line tools inside Windows.
Having WSL allows things to be done much more straightforward, processing the files in your local windows hard drives.
Please note: Maybe you have enough using GitBash.
Error installing: WslRegisterDistribution failed with error: 0x80070057
When I installed it I found this error and look for an answer online. I found no solutions and many people suffering from the same problem, so I decided to publish an article on how to make it work.
Microsoft use Powershell to activate the features disabled in Windows, I did the same with Command Line, which I found more convenient for most of the non extremely tech people.
You will need:
For x64 systems: Version 1903 or higher, with Build 18362 or higher.
You can check your version of windows opening a Terminal (CMD.exe) and typing:
winver
For ARM64 systems: Version 2004 or higher, with Build 19041 or higher.
I’m not covering installing WSL for ARM, only for Intel/AMD Desktop/Laptops with Windows 10.
If you’re unsure, you can open a Terminal (CMD.exe) and run:
The recommended way to install Ubuntu on WSL is through the Microsoft Store.
The following Ubuntu releases are available as apps on the Microsoft Store:
Ubuntu 16.04 LTS (Xenial) is the first release available for WSL. It supports the x64 architecture only. (offline installer: x64)
Ubuntu 18.04 LTS (Bionic) is the second LTS release and the first one supporting ARM64 systems, too. (offline installers: x64, ARM64)
Ubuntu 20.04 LTS (Focal) is the current LTS release, supporting both x64 and ARM64 architecture.
Ubuntu (without the release version) always follows the recommended release, switching over to the next one when it gets the first point release. Right now it installs Ubuntu 20.04 LTS.
Each app creates a separate root file system in which Ubuntu shells are opened but app updates don’t change the root file system afterwards. Installing a different app in parallel creates a different root file system allowing you to have both Ubuntu LTS releases installed and running in case you need it for keeping compatibility with other external systems. You can also upgrade your Ubuntu 16.04 to 18.04 by running ‘do-release-upgrade’ and have three different systems running in parallel, separating production and sandboxes for experiments.
But if you prefer, instead of using the Windows Store, you can download the appx.
In the same page mentioned you can do it for several versions, I attach the link for Ubuntu 20.04 LTS: https://aka.ms/wslubuntu2004
Assuming you used the Windows Store, if you did not reboot and try now to execute it for the first time, or you go to the Command Line and write bash, or open Ubuntu from Windows menu, whatever method you use, you’ll get the abovementioned error.
If that happens to you, just reboot and when you open it will work and will start the install and ask for a user and password:
From here you’re able to update the system, execute the text commands available in Linux, access to the Windows drives, launch htop, git, Python3, apt, wget… copy and paste between windows and Linux terminal, share PATH…
And of course you can run CTOP.py
Take in count that the space reported in / partition is not real, and that you have a 4GB swap.
Is something very simple, but will help my student friends to validate Input from Keyboard without losing too many hours.
The Input Validation Classes I create in PHP for Privalia or in my PHP Catalonia Framework, are much, much, more powerful, allowing the validation of complete forms, rendering errors, etc… although they were created for Web, and not for Keyboard input.
It recursively goes to all the subdirectories looking for .py files, and then it counts the lines.
I updated the price of my books to be the minimum allowed by LeanPub, to $5 USD, and created a bundle of two of them for $7 USD.
So people can benefit from this during the lock down.
I’ve updated the Python Combat Guide book with a sample of using Paramiko Libraries for SSH, and increased the Object Oriented Programing and Unit Testing, sections. I also added some books to the Bibliography.
I’ve read the postmortem initial analysis from Slack’s incident. It’s really interesting.
I cannot share it, but I guess that at some point they will publish it on their blog:
I’m teaching a friend how to code. Covid-19 has affected many people, with many jobs loss in many sectors. I encouraged him to learn to code and I helped him to access to a course offered by the Catalan government, but they let him down with a really difficult exam in the very last moment.
I encouraged him to continue and offered to help him, and after a start with several courses via Internet, that were not very useful, I started teaching and training him personally. And I did the way the companies need: Python, PyCharm, Git, Linux, VirtualBox, Web…
I told him since the beginning that I can help him, yes, but 90% has to come from his effort. I’m really happy to see that he is really doing the effort and how much he advanced.
Was not easy as I had to combine it with the classes in the university, my work, the Open Source projects, and my life… but I’m proud of him and of the effort he is doing.
Today he remembered me how shocked he was when I showed some Python builtin libraries, like datetime, and he saw in PyCharm, that the code of that library alone, has 2,476 lines.
I wanted to explain that we can get to create a program with thousands of lines of code, easily, so I decided to write a small program to count the number of lines of our programs.
I quickly wrote it in bash in one single line:
i_counter=0; for s_filename in `find . -name "*.py"`; do wc --lines $s_filename; i_num=`cat $s_filename | wc --lines`; i_counter=$((i_counter+i_num)); done; echo "Total lines: $i_counter"
Execute it from inside your directory.
It can be improved and optimized very easily.
wc is executed so it prints the lines and the filename, and then is executed as a pipe from cat to capture just the number, so the first one is not really needed. The same can be achieved with echo as we have the variables $s_filename and $i_counter
You can filter out test files or others by using the find options or grep -v, for example to exclude test directories or files.
Number of files can very easily added too.
Using “” for avoiding problems with files with spaces.
The better and most modern $() way to execute, instead of “ can be used.
I made some improvements abovementioned and uploaded this as a several lines script:
