Category Archives: Software development

Creating Jenkins configurations for your projects

Obviously for companies is a must, but if you work in your own projects, it will be super great that you configure Jenkins, so you have continuous feedback about if something breaks.

I’ll show you how to configure Jenkins for several projects using only your main computer/laptop.

Check my past article about setting up Jenkins in Docker.

Adding a new Freestyle project

Click on top left: New item.

Then give it an appropriate name and choose Freestyle Project.

Take in count that the name given will be used as the name of the workspace, so you may want to avoid special characters.

It is very convenient to let Jenkins deal with your repository changes instead of using shell commands. So I’m going to fill this section.

I also provided credentials, so Jenkins can log to my Gitlab.

This kind of project is the most simple and we will use the same Docker Container where Jenkins resides, to run the Unit Testing of our code.

We are going to select to Build periodically.

If your Server is in Internet, you can active the Web Hooks so your Jenkins is noticed via a web connection from GitLab, GitHub or your CVS provider. As I’m strictly running this at home, Jenkins will be periodically check for changes in the repository and do nothing if there are no changes.

I’ll set H * * * * so Jenkins will try every hour.

Go down and select Add Build Step:

Select Execute shell.

Then add a basic echo command to print in the Console Output, and ls command so you see what is in the default’s directory your shell script is executing in.

Now save your project.

And go back to Dashboard.

Click inside of Neurona.cat to view Project’s Dashboard.

Click: Build Now. And then click on the Build task (Apr 5, 2021, 10:31 AM)

Click on Console Output.

You’ll see a verbose log of everything that happened.

You’ll see for example that Jenkins has put the script on the path of the git project folder that we instructed before to clone/pull.

This example doesn’t have test. Let’s see one with Unit Test.

Running Unit Testing with pytest

If we enter the project CTOP and then select Configure you’ll see the steps I did for making it do the Unite Testing.

In my case I wanted to have several steps, one per each Unit Test file.

If each one of them I’ve to enter the right directory before launching any test.

If you open the last successful build and and select Console Output you’ll see all the tests, going well.

If a test will go wrong, pytest will exit with Exit Code different of 0, and so Jenkins will detect it and show that the Build Fails.

Building a Project from Pipeline

Pipeline is the set of plugins that allow us to do Continuous Deployment.

Inform the information about your git project.

Then in your gitlab or github project create a file named Jenkinsfile.

Jenkins will look for it when it clones your repo, to build the Pipeline.

Here is my Jenkinsfile in https://gitlab.com/carles.mateo/python_combat_guide/-/blob/master/Jenkinsfile

pipeline {
    agent any
    stages {
        stage('Show Environment') {
            steps {
                echo 'Showing the environment'
                sh 'ls -hal'
            }
        }
        stage('Updating from repository') {
            steps {
                echo 'Grabbing from repository'
                withCredentials([usernamePassword(credentialsId: 'ssh-fast', usernameVariable: 'USERNAME', passwordVariable: 'USERPASS')]) {
                    script {
                        sh "sshpass -p '$USERPASS' -v ssh -o StrictHostKeyChecking=no $USERNAME@$ip_fast 'git clone https://gitlab.com/carles.mateo/python_combat_guide.git; cd python_combat_guide; git pull'"
                    }
                }
            }
        }
        stage('Build Docker Image') {
            steps {
                echo 'Building Docker Container'
                withCredentials([usernamePassword(credentialsId: 'ssh-fast', usernameVariable: 'USERNAME', passwordVariable: 'USERPASS')]) {
                    script {
                        sh "sshpass -p '$USERPASS' -v ssh -o StrictHostKeyChecking=no $USERNAME@$ip_fast 'cd python_combat_guide; docker build -t python_combat_guide .'"
                    }
                }
            }
        }
        stage('Run the Tests') {
            steps {
                echo "Running the tests from the Container"
                withCredentials([usernamePassword(credentialsId: 'ssh-fast', usernameVariable: 'USERNAME', passwordVariable: 'USERPASS')]) {
                    script {
                        sh "sshpass -p '$USERPASS' -v ssh -o StrictHostKeyChecking=no $USERNAME@$ip_fast 'cd python_combat_guide; docker run  python_combat_guide'"
                    }
                }
            }
        }
    }
}

My Jenkins Docker installation has the sshpass command, and I use it to connect via SSH, with username and Password to the server defined by ip_fast environment variable.

We defined the variable ip_fast in Manage Jenkins > Configure System.

There in Global Properties , Environment Variables I defined ip_fast:

In the Build Server I’ll make a new user and allow it to build Docker:

sudo adduser jenkins_build

sudo usermod -aG docker jenkins_build

The Credentials can be managed from Manage Jenkins > Manage Credentials.

You can see how I use all this combined in the Jenkinsfile so I don’t have to store credentials in the CVS and Jenkins (Docker Container) will connect via SSH to make the computer after ip_fast Ip, to build and run another Container. That Container will run with a command to do the Unit Testing. If something goes wrong, that is, if any program return an Exit Code different from 0, Jenkins will consider the build fail.

Take in count that $? only stores the Exit Code of the last program. So be careful if you pass multiple commands in one single line, as this may mask an error.

Separating the execution in multiple Stages helps to save time, as after a failure, execution will not continue.

Also visually is easy to see where the error is.

A base Dockerfile for my Jenkins deployments

So I share with you my base Jenkins Dockerfile, so you can spawn a new Jenkins for your projects.

The Dockerfile installs Ubuntu 20.04 LTS as base image and add the required packages to run jenkins but also Development and Testing tools to use inside the Container to run Unit Testing on your code, for example. So you don’t need external Servers, for instance.

You will need 3 files:

  • Dockerfile
  • docker_run_jenkins.sh
  • requirements.txt

The requirements.txt file contains your PIP3 dependencies. In my case I only have pytest version 4.6.9 which is the default installed with Ubuntu 20.04, however, this way, I enforce that this and not any posterior version will be installed.

File requirements.txt:

pytest==4.6.9

The file docker_run_jenkins.txt start Jenkins when the Container is run and it will wait until the initial Admin password is generated and then it will display it.

File docker_run_jenkins.sh:

#!/bin/bash

echo "Starting Jenkins..."

service jenkins start

echo "Configure jenkins in http://127.0.0.1:8080"

s_JENKINS_PASSWORD_FILE="/var/lib/jenkins/secrets/initialAdminPassword"

i_PASSWORD_PRINTED=0

while [ true ];
do
    sleep 1
    if [ $i_PASSWORD_PRINTED -eq 1 ];
    then
        # We are nice with multitasking
        sleep 60
        continue
    fi

    if [ ! -f "$s_JENKINS_PASSWORD_FILE" ];
    then
        echo "File $s_FILE_ORIGIN does not exist"
    else
        echo "Password for Admin is:"
        cat $s_JENKINS_PASSWORD_FILE
        i_PASSWORD_PRINTED=1
    fi
done

That file has the objective to show you the default admin password, but you don’t need to do that, you can just start a shell into the Container and check manually by yourself.

However I added it to make it easier for you.

And finally you have the Dockerfile:

FROM ubuntu:20.04

LABEL Author="Carles Mateo" \
      Email="jenkins@carlesmateo.com" \
      MAINTAINER="Carles Mateo"

# Build this file with:
# sudo docker build -f Dockerfile -t jenkins:base .
# Run detached:
# sudo docker run --name jenkins_base -d -p 8080:8080 jenkins:base
# Run seeing the password:
# sudo docker run --name jenkins_base -p 8080:8080 -i -t jenkins:base
# After you CTRL + C you will continue with:
# sudo docker start
# To debug:
# sudo docker run --name jenkins_base -p 8080:8080 -i -t jenkins:base /bin/bash

ARG DEBIAN_FRONTEND=noninteractive

ENV SERVICE jenkins

RUN set -ex

RUN echo "Creating directories and copying code" \
    && mkdir -p /opt/${SERVICE}

COPY requirements.txt \
    docker_run_jenkins.sh \
    /opt/${SERVICE}/

# Java with Ubuntu 20.04 LST is 11, which is compatible with Jenkins.
RUN apt update \
    && apt install -y default-jdk \
    && apt install -y wget curl gnupg2 \
    && apt install -y git \
    && apt install -y python3 python3.8-venv python3-pip \
    && apt install -y python3-dev libsasl2-dev libldap2-dev libssl-dev \
    && apt install -y python3-venv \
    && apt install -y python3-pytest \
    && apt install -y sshpass \
    && wget -qO - https://pkg.jenkins.io/debian-stable/jenkins.io.key | apt-key add - \
    && echo "deb http://pkg.jenkins.io/debian-stable binary/" > /etc/apt/sources.list.d/jenkins.list \
    && apt update \
    && apt -y install jenkins \
    && apt-get clean

RUN echo "Setting work directory and listening port"
WORKDIR /opt/${SERVICE}

RUN chmod +x docker_run_jenkins.sh

RUN pip3 install --upgrade pip \
    && pip3 install -r requirements.txt


EXPOSE 8080


ENTRYPOINT ["./docker_run_jenkins.sh"]

Build the Container

docker build -f Dockerfile -t jenkins:base .

Run the Container displaying the password

sudo docker run --name jenkins_base -p 8080:8080 -i -t jenkins:base

You need this password for starting the configuration process through the web.

Visit http://127.0.0.1:8080 to configure Jenkins.

Configure as usual

Resuming after CTRL + C

After you configured it, on the terminal, press CTRL + C.

And continue, detached, by running:

sudo docker start jenkins_base

The image is 1.2GB in size, and will allow you to run Python3, Virtual Environments, Unit Testing with pytest and has Java 11 (not all versions of Java are compatible with Jenkins), use sshpass to access other Servers via SSH with Username and Password…

Why I propose you to use Python 3.8, at least, for your Internal Automation Tools in Docker Containers

This article is written at 2021-03-22 so this conclusion will evolve as time passes.

Some of my articles are checked after 7 years, so be advised this choice will not be valid in a year. Although the reasoning and considerations to take in count will be the same.

I answer to the question: Why Carles, do you suggest to adopt Python 3.8, and not 3.9 or 3.7 for our Internal Automation Tools?.

Reliability and Maturity

If you look at page https://devguide.python.org/#status-of-python-branches you will see the next table:

So you can see that:

  • Python 3.6 was released on 2016-12-23 and will get EOL on 2021-12-23.
    • That’s EOL in 9 months. We don’t want to recommend that.
  • Python 3.7 was released on 2018-06-27 and will get EOL 2023-06-27.
    • That’s 2 years and 3 months from now. The Status of development is focus in Security bugfixes.
  • Python 3.9 was released 2020-10-05 that’s 5 months approx from now.
    • Honestly, I don’t recommend for Production a version of Software that has not been in the market for a year.
      • Most of the bugs and security bugs appears before the first year.
      • New features released, often are not widely fully tested , and bugs found and fixed, once a year has passed.
  • Python 3.8 was released on 2019-10-14.
    • That means that the new features have been tested for a year and five months approximately.
    • This is enough time to make appear most bugs.
    • EOL is 2024-10, that is 3 years and 7 months from now. A good balance of EOL for the effort to standardize.
    • Finally Python 3.8 is the Python mainline for Ubuntu 20.04 LTS.
      • If our deploy strategy is synchronized, we want to use Long Time Support versions, of course.

So my recommendation would be, at least for your internal tools, to use containers based in Ubuntu 20.04 LTS with Python 3.8.

We know Docker images will be bigger using Ubuntu 20.04 LTS than using other images, but that disk space is really a small difference, and we get the advantage of being able to install additional packages in the Containers if we need to debug.

An Ubuntu 20.04 Image with Pyhton 3.8 and pytest, uses 540 MB.

This is a small amount of space nowadays. Even if very basic Alpine images can use 25MB only, when you install Python they start to grow close to Ubuntu, to 360MB. The difference is not much, and if you used Alpine and you have suffered from Community packages being updated and becoming incompatible with wheel and you lost hours fixing the dependencies, you’ll really appreciate using my Ubuntu LTS packages approach.

compress_old.sh A simple Bash script to compress files in a directory, older than n days

I use this script for my needs, to compress logs and core dumps older than some days, in order to Cron that and save disk space.

You can also download it from here:

https://gitlab.com/carles.mateo/blog.carlesmateo.com-source-code/-/blob/master/compress_old.sh

#!/bin/bash

# By Carles Mateo - https://blog.carlesmateo.com
# Compress older than two days files.
# I use for logs and core dumps. Normally at /var/core/

# =======================================================0
# FUNCTIONS
# =======================================================0


function quit {
    # Quits with message in param1 and error code in param2
    s_MESSAGE=$1
    i_EXIT_CODE=$2

    echo $s_MESSAGE
    exit $i_EXIT_CODE
}

function add_ending_slash {
    # Check if Path has ending /
    s_LAST_CHAR_PATH=$(echo $s_PATH | tail -c 2)

    if [ "$s_LAST_CHAR_PATH" != "/" ];
    then
        s_PATH="$s_PATH/"
    fi
}

function get_list_files {
    # Never follow symbolic links
    # Show only files
    # Do not enter into subdirs
    # Show file modified more than X days ago
    # Find will return the path already
    s_LIST_FILES=$(find -P $s_PATH -maxdepth 1 -type f -mtime +$i_DAYS | tr " " "|")
}

function check_dir_exists {
    s_DIRECTORY="$1"
    if [ ! -d "$s_DIRECTORY" ];
    then
        quit "Directory $s_DIRECTORY does not exist." 1
    fi
}

function compress_files {
    echo "Compressing files from $s_PATH modified more than $i_DAYS ago..."
    for s_FILENAME in $s_LIST_FILES
    do
        s_FILENAME_SANITIZED=$(echo $s_FILENAME | tr "|" " ")
        s_FILEPATH="$s_PATH$s_FILENAME_SANITIZED"
        echo "Compressing $s_FILENAME_SANITIZED..."
        # Double quotes around $s_FILENAME_SANITIZED avoid files with spaces failing
        gzip "$s_FILENAME_SANITIZED"
        i_ERROR=$?
        if [ $i_ERROR -ne 0 ];
        then
            echo "Error $i_ERROR happened"
        fi
    done

}


# =======================================================0
# MAIN PROGRAM
# =======================================================0

# Check Number of parameters
if [ "$#" -lt 1 ] || [ "$#" -gt 2 ];
then
    quit "Illegal number of parameters. Pass a directory and optionally the number of days to exclude from mtime. Like: compress_old.sh /var/log 2" 1
fi

s_PATH=$1

if [ "$#" -eq 2 ];
then
    i_DAYS=$2
else
    i_DAYS=2
fi

add_ending_slash

check_dir_exists $s_PATH

get_list_files

compress_files
Fragment of the code in gitlab

If you want to compress everything in the current directory, event files modified today run with:

./compress_old.sh ./ 0

A simple script to upload a PIP package

If you want to create a package and distribute it like through pip in record time, you can customize my script from cmemgzip for Ubuntu 20.04.

Here is the official documentation if you want to do everything manually:

https://packaging.python.org/tutorials/packaging-projects

Here is the script customized for Test Environment.

You’ll need to create a Test account in test.pypi.org

#!/bin/bash

PACKAGE="cmemgzip-test"
mkdir $PACKAGE
mkdir $PACKAGE/src
mkdir $PACKAGE/src/$PACKAGE
mkdir $PACKAGE/tests

cp LICENSE $PACKAGE/

echo "[build-system]" > $PACKAGE/pyproject.toml
echo "requires = [" >> $PACKAGE/pyproject.toml
echo '    "setuptools>=42",' >> $PACKAGE/pyproject.toml
echo '    "wheel"' >> $PACKAGE/pyproject.toml
echo "]" >> $PACKAGE/pyproject.toml
echo 'build-backend = "setuptools.build_meta"' >> $PACKAGE/pyproject.toml

cat <<EOF > $PACKAGE/setup.cfg
[metadata]
name = cmemgzip
version = 0.4.1
author = Carles Mateo
author_email = cmemgzip@carlesmateo.com
description = Compresses files in memory and replaces the original by a .gz file when there is no space on drive.
long_description = file: README.md
long_description_content_type = text/markdown
url = https://gitlab.com/carles.mateo/cmemgzip
project_urls =
    Bug Tracker = https://gitlab.com/carles.mateo/cmemgzip/issues
classifiers =
    Programming Language :: Python :: 3
    License :: OSI Approved :: MIT License
    Operating System :: OS Independent

[options]
package_dir =
    = src
packages = find:
python_requires = >=3.6

[options.packages.find]
where = src
EOF

cp README.md $PACKAGE/
cp manual-cmemgzip.pdf $PACKAGE/
cp cmemgzip.py $PACKAGE/src/$PACKAGE/
touch $PACKAGE/src/$PACKAGE/__init__.py
cp test_*.py $PACKAGE/tests/


python3 -m pip install --upgrade build

# Install dependencies
sudo apt-get install python3.8-venv

python3 -m pip install --user --upgrade twine


echo
echo "Entering into directory $PACKAGE"
cd $PACKAGE

echo
echo "Generating distribution binaries"
python3 -m build

# Create account in: https://test.pypi.org/manage/account/

# Create API Token
# https://test.pypi.org/manage/account/

echo
echo "Going to upload the packages. Use your username and password"
echo
python3 -m twine upload --repository testpypi dist/cmemgzip*

The changes for the script to production are just a different package name, and last line:

python3 -m twine upload --repository pypi dist/cmemgzip*

Obviously you’ll need to use credentials for Production.

Reinstall PIP in Windows 10 after it got removed

If accidentally you removed PIP from your windows machine, or you attempted a PIP upgrade which failed after removing the current version, and let you unable to install it anymore, you can address it this way.

python -m ensurepip --default-pip

After this, you can upgrade it:

python -m install --upgrade pip setuptools wheel

A live session refactoring and adding Unit Testing to my Python3 project cmemgzip

I refactor and add unit testing to my actual project cmemgzip while I comment every step so you can learn the whys and the reasoning.

Open video in full screen with max 1080 quality, in order to see the code clearly.

Update 2021-03-03: I added a third part. I’m tired but still is worth watching.

Raspberry Pi: Solving the problem GPIO.setup(self.number, GPIO.IN, self.GPIO_PULL_UPS[self._pull]) RuntimeError: Not running on a RPi! in Ubuntu 20.04LTS

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:

sudo apt install python3-pip python3-gpiozero
sudo pip3 install giozero

In order to run the 3D LED Christmas Tree code samples

sudo pip3 install colorzero
sudo pip3 install rpi.gpio --upgrade

Reboot

It may be not required in some cases.

Download the Source code

https://github.com/ThePiHut/rgbxmastree#rgbxmastree

Run the samples as root

I saw many people stuck, in the forums, because of that.

To work with the LEDs you need to run the samples as root.

Where I used it?

I used it in my Open Source monitor Software CTOP.py in order to show the plugins/extensions capability of it. :)

A simple Bash one line script to log the temperature of your HDDs and CPUs in Ubuntu

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.

News from the blog 2021-01-11

Happy New Year to all.

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:

https://slack.engineering/

  • As I’m giving more Python Classes I decided to write a book to teach to code in Python for non-programmers.