Fedora 41 : python and Federated Message Bus in Fedora Linux Distro.

Federated Message Bus is a library built on ZeroMQ using the PyZMQ Python bindings. fedmsg aims to make it easy to connect services together using ZeroMQ publishers and subscribers.

You can use this python package named fedmsg to use this functionality ...

This is the source code :

import fedmsg
from fedmsg import *

import os
# Set the routing_nitpicky flag to True
os.environ['FEDMSG_ROUTING_NITPICKY'] = 'True'


config = fedmsg.config.load_config([],None)
config['mute'] = True
config['timeout'] = 0

for name, endpoint, topic, msg in fedmsg.tail_messages(**config):
    print ("name ", name)

This is the result :

[mythcat@fedora FedoraMessaging]$ python fedmsg_001.py
No routing policy defined for "org.fedoraproject.prod.copr.build.start" but routing_nitpicky is False so the message is being treated as authorized.
name  fedora-infrastructure
No routing policy defined for "org.fedoraproject.prod.copr.chroot.start" but routing_nitpicky is False so the message is being treated as authorized.
name  fedora-infrastructure
No routing policy defined for "org.fedoraproject.prod.github.check_run" but routing_nitpicky is False so the message is being treated as authorized.
name  fedora-infrastructure
No routing policy defined for "org.fedoraproject.prod.github.pull_request_review" but routing_nitpicky is False so the message is being treated as authorized.
name  fedora-infrastructure
No routing policy defined for "org.fedoraproject.prod.github.pull_request_review_comment" but routing_nitpicky is False so the message is being treated as authorized.
name  fedora-infrastructure ... 

Fedora 40 : Fedora CoreOS - part 001.

The documentation for Fedora 40 CoreOS can be found on the official webpage.

I download the fedora-coreos-40.20240331.1.0-virtualbox.x86_64.ova file.

You can use double click to open with the VirtualBox application, see the next screenshot:

Fedora use ssh keys and a user named core, use these steps from the official webpage to change the password for this user.

The result will be this:

You need to use these steps to create a password based on the butane and ignition software to login with the ssh-rsa.

Fedora 41 : Python and the Fedora Messaging Infrastructure - part 001.

Yesterday I tried to use Fedora Messaging.

You can find the documentation on the official page./div>

I created a working folder called FedoraMessaging:

[mythcat@fedora PythonProjects]$ mkdir FedoraMessaging
[mythcat@fedora PythonProjects]$ cd FedoraMessaging

You need to install the fedora-messaging and rabbitmq-server packages.

[root@fedora FedoraMessaging]# dnf5 install fedora-messaging
Updating and loading repositories:
Repositories loaded.
Package                             Arch    Version                       Repository         Size
Installing:                                                                                      
 fedora-messaging                   noarch  3.5.0-1.fc41                  rawhide        38.6 KiB
...
[root@fedora FedoraMessaging]# dnf install rabbitmq-server

At some point it will ask for a reboot.

You need to install the python package named fedora-messaging.

[root@fedora FedoraMessaging]# pip install --user fedora-messaging
Collecting fedora-messaging
...
Installing collected packages: pytz, incremental, wrapt, tomli, rpds-py, pyasn1, pika, hyperlink, constantly, attrs, 
referencing, pyasn1-modules, automat, twisted, jsonschema-specifications, service-identity, jsonschema, crochet, 
fedora-messaging
Successfully installed attrs-23.2.0 automat-22.10.0 constantly-23.10.4 crochet-2.1.1 fedora-messaging-3.5.0 
hyperlink-21.0.0 incremental-22.10.0 jsonschema-4.21.1 jsonschema-specifications-2023.12.1 pika-1.3.2 pyasn1-0.6.0 
pyasn1-modules-0.4.0 pytz-2024.1 referencing-0.34.0 rpds-py-0.18.0 service-identity-24.1.0 tomli-2.0.1 twisted-24.3.0 
wrapt-1.16.0

You need to start the broker:

[mythcat@fedora FedoraMessaging]$ sudo systemctl start rabbitmq-server

I used the source code from the documentation to test its functionality with a python script named hello_test.py.

from fedora_messaging import api, config

config.conf.setup_logging()
api.consume(lambda message: print(message))

from fedora_messaging import api, config

config.conf.setup_logging()
api.publish(api.Message(topic="hello by mythcat", body={"Hello": "world!"}))

I ran it and got this response:

[mythcat@fedora FedoraMessaging]$ python hello_test.py
[fedora_messaging.message INFO] Registering the 'base.message' key as the '<class 'fedora_messaging.message.Message'>' 
class in the Message class registry
[fedora_messaging.twisted.protocol INFO] Waiting for 0 consumer(s) to finish processing before halting
[fedora_messaging.twisted.protocol INFO] Finished canceling 0 consumers
[fedora_messaging.twisted.protocol INFO] Disconnect requested, but AMQP connection already gone

I created another python script named my_consumer.py, to check if this works:

from fedora_messaging import api, config
# Setup logging
config.conf.setup_logging()
# Define the callback function to process messages
def process_message(message):
    # Check if the message topic matches "hello by mythcat"
    if message.topic == "hello by mythcat":
        print(f"Received message: {message.body}")
    else:
        print(f"Ignoring message with topic: {message.topic}")
# Consume messages
api.consume(process_message)

I ran it and got this response:

[mythcat@fedora FedoraMessaging]$ python my_consumer.py
[fedora_messaging.twisted.protocol INFO] Successfully registered AMQP consumer Consumer(queue=amq.gen-9lKk7sGeYY5I40bdc5VrzQ,
callback=<function process_message at 0x7fdb0f5da160>)
[fedora_messaging.message INFO] Registering the 'base.message' key as the '<class 'fedora_messaging.message.Message'>'
class in the Message class registry
[fedora_messaging.twisted.consumer INFO] Consuming message from topic hello by mythcat 
(message id 800a1540-1e91-4b4a-a125-15e33eebb699)
Received message: {'Hello': 'world!'}
[fedora_messaging.twisted.consumer INFO] Successfully consumed message from topic hello by mythcat 
(message id 800a1540-1e91-4b4a-a125-15e33eebb699)

It can be seen that the answer is received and displayed correctly.

Fedora 41 : Memstrack tool.

A runtime memory allocation tracer, like a hot spot analyzer for memory allocation, can help analyze overall memory usage, peak memory usage, kernel module memory usage, all combined with stacktrace. Userspace memory trace is planned and not yet implemented.

This tool works by tracing all page-level memory allocation events in kernel (currently supports using perf or ftrace), and actively integrate the events into a stack trace tree. It can also work with kernel's page owner log file and use as a memory usage viewer.

I tested this tool today and it is quite useful for development and monitoring the operating system, it seems to work very well, you can even see in the screenshot how ...

You can find this project on the GitHub repo.

Fedora 40 : Fix emergency run mode - part 001.

Run this commands to see errors and all failed systemd units:

[root@fedora mythcat]# dmesg | grep err
[root@fedora mythcat]# systemctl status --failed --all

If you get an error like this:

Recovery unable to mount /home

... check the /etc/fstab file to see how your home is set.

News : Fedora 40 Beta RC 1.10 compose ...

The Fedora Linux 40 Beta RC 1.10 compose is GO and will be shipped live on Tuesday, 26th March 2024.

This announcement was made on the devel-announce list by Aoife Moloney.

Aoife Moloney, the Fedora Operations Architect, has recently joined the Fedora community.

The Beta RC compose serves as a preliminary version of the upcoming Fedora release and allows Quality Engineering (QE) to thoroughly test the system and identify any critical issues before the final release.

You can find schedule for Fedora 40 on the official website.

News : Flutter on Fedora 40 - the run debug info.

The run command comes with info about the running process, see:

[mythcat@fedora examples]$ ../flutter/bin/flutter run
Launching lib/main.dart on Linux in debug mode...
Building Linux application...                                           
Syncing files to device Linux...                                 1,488ms

Flutter run key commands.
r Hot reload. 🔥🔥🔥
R Hot restart.
h List all available interactive commands.
d Detach (terminate "flutter run" but leave application running).
c Clear the screen
q Quit (terminate the application on the device).

A Dart VM Service on Linux is available at: http://127.0.0.1:38903/k8tmzU7n0NQ=/
The Flutter DevTools debugger and profiler on Linux is available at:
http://127.0.0.1:9100?uri=http://127.0.0.1:38903/k8tmzU7n0NQ=/

If you open that URL you will see this type of informations:

Fedora 40 : Spectacle tool.

Spectacle is a screenshot taking utility for the KDE desktop. Spectacle can also be used in non-KDE X11 desktop environments.

This is the GitHub project for this tool.

[root@fedora mythcat]# dnf5 install spectacle.x86_64
Updating and loading repositories:
Repositories loaded.
Package                       Arch   Version                 Repository      Size
Installing:                                                                      
 spectacle                    x86_64 24.02.0-1.fc41          updates-te   4.8 MiB
Installing dependencies:                                                         
...

This is an screenshot with this tool:

News : Introducing GNOME 46

Fedora 40 : sngrep tool.

The sngrep is a tool for displaying SIP calls message flows from terminal and supports live capture to display realtime SIP packets and can also be used as PCAP viewer.

[mythcat@fedora ~]# dnf copr enable irontec/sngrep
[mythcat@fedora ~]# dnf install sngrep
[mythcat@fedora ~]# exit
[mythcat@fedora ~]$ sudo sngrep  -d ens1 -O save.pcap port 8080 and udp

The result is this:

News : Flutter on Fedora 40.

Flutter transforms the development process. Build, test, and deploy beautiful mobile, web, desktop, and embedded experiences from a single codebase.

Read more on the official webpage.

Theoretically, Flutter can be used much easier in the Fedora 40 Linux distribution than in a Windows operating system.

The Windows installation method requires more complicated steps with the use of S.D.K. and settings of Android Studio I.D.E. .

Here are the steps you need to follow for a default installation.

[mythcat@fedora ~]$ mkdir ~/FlutterProjects
[mythcat@fedora ~]$ cd FlutterProjects/
[mythcat@fedora ~]$ wget https://storage.googleapis.com/flutter_infra_release/releases
/stable/linux/flutter_linux_3.3.10-stable.tar.xz
[mythcat@fedora ~]$ tar xf flutter_linux_3.3.10-stable.tar.xz
[mythcat@fedora ~]$
...

[mythcat@fedora FlutterProjects]$ ./flutter/bin/flutter doctor

┌─────────────────────────────────────────────────────────┐
│ A new version of Flutter is available!                  │
│                                                         │
│ To update to the latest version, run "flutter upgrade". │
└─────────────────────────────────────────────────────────┘
...

      If the Android SDK has been installed to a custom location, please use
      `flutter config --android-sdk` to update to that location.

[✗] Chrome - develop for the web (Cannot find Chrome executable at
    google-chrome)
    ! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[✓] Linux toolchain - develop for Linux desktop
[!] Android Studio (not installed)
[✓] VS Code (version 1.87.2)
[✓] Connected device (1 available)
[✓] HTTP Host Availability

! Doctor found issues in 3 categories.
[mythcat@fedora FlutterProjects]$ ./flutter/bin/flutter upgrade

...

    ! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[✓] Linux toolchain - develop for Linux desktop
[!] Android Studio (not installed)
[✓] VS Code (version 1.87.2)
[✓] Connected device (1 available)
[✓] Network resources

! Doctor found issues in 4 categories.

[mythcat@fedora FlutterProjects]$ ./flutter/bin/flutter config --enable-linux-desktop
Setting "enable-linux-desktop" value to "true".

You may need to restart any open editors for them to read new settings.

[mythcat@fedora FlutterProjects]$ mkdir examples
[mythcat@fedora FlutterProjects]$ cd examples/

[mythcat@fedora examples]$ ../flutter/bin/flutter create .
Creating project ....
Resolving dependencies... (5.1s)
Got dependencies.
Wrote 129 files.

All done!
You can find general documentation for Flutter at: https://docs.flutter.dev/
Detailed API documentation is available at: https://api.flutter.dev/
If you prefer video documentation, consider:
https://www.youtube.com/c/flutterdev

In order to run your application, type:

  $ cd .
  $ flutter run

Your application code is in ./lib/main.dart.

[mythcat@fedora examples]$ cd .
[mythcat@fedora examples]$ ls
analysis_options.yaml  ios    macos         README.md  windows
android                lib    pubspec.lock  test
examples.iml           linux  pubspec.yaml  web
[mythcat@fedora examples]$ ../flutter/bin/flutter run

The result is this simple default example:

News : SELinux wizzard tool !

I found today in Fedora linux this tool for SELinux with a GUI that allows creating linux security policies.

I will write a little about this system because it is a very good solution.

When I started studying selinux, it was not very well implemented and it seems that the interest of users to be protected is higher.

As you well know, the starting points are network security and data protection and kernel-level intrusions into software.

For those who don't know, SELinux is a system that allows limiting defined resources and allowing other actions or not.

I tested the tool and I can say that it solves only the standard file creation part without the possibility of selecting the SELinux bools variables.

If the one who created this tool will continue to be a very good tool.

It's currently a wizzard interface, I'd call it a Node Editor to allow the assembly of different processing blocks (nodes) into combinations that feed data to each other along connections you specify to produce complex effects.

After completing the steps in the wizard, you will have some default files.

I used the name firefox because the security of the browser is very low at the moment.

Here are some images of this tool:

News : ... about new about Google Analytics 4.

I found at Google.com analytics academy this message that urges us to go through the courses from the skillshop.exceedlms.com website.

It seems to pass this is quite important if they offered free courses:

These courses are about Universal Analytics. Starting July 1, 2023, standard UA properties will stop processing data (July 1, 2024 for UA 360 properties). Learn about Google Analytics 4, our next-generation measurement solution, with these free courses on Skillshop.

News : VirtualBox 7.0.14 released! from Oracle.

Oracle today released a 7.0 maintenance release which improves stability and fixes regressions. See the Changelog

I also use a version of Fedora running on VirtualBox for tests and rapid development.

Most use Linux on older hardware as a backup OS...

You can use Linux with specific non-default settings for good security of the operating system, but it does not make it invincible.

I don't know if VirtualBox solved the resize of the virtual partition - this was the last issue I encountered with this tool, but it is useful if you want to test something quickly.

Fedora 40 : Find version and GlibC flaw !

Because today I saw a video about the GlibC flaw that lets attackers get root on major distros, I will show an easy way to find the version of this lib with dnf and dnf5 tools:

[root@fedora var]# dnf in glibc
Last metadata expiration check: 0:04:06 ago on Wed 31 Jan 2024 10:25:13 PM EET.
Package glibc-2.38.9000-35.fc40.x86_64 is already installed.
Package glibc-2.38.9000-35.fc40.i686 is already installed.
Dependencies resolved.
Nothing to do.
Complete!
[root@fedora var]# dnf5 in glibc
Updating and loading repositories:
Repositories loaded.
Package "glibc-2.38.9000-35.fc40.x86_64" is already installed.
Package "glibc-2.38.9000-35.fc40.i686" is already installed.

You can see in the name is add the version: 2.38.9000-35.fc40.x86_64.

This is the video about GlibC from Bits inside by René Rebe.