jbub

About

Fri, 03 Apr 2020 02:13:50 +0000

School

2010 - 2015 - UMB, BB, Applied computer science
2004 - 2008 - SPŠ J. Murgaša, BB, Computer Systems Networking and Telecommunications

Thesis

Master (2015), Documentation generator Sphinx and its use for the scientific program DIRAC
Bachelor (2013), Improving web application comprehension using dynamic program analysis

Work experience

2018 - 2020 Exponea, Software Engineer (Python, Go)

core member of the data pipeline team
responsible for receiving, processing, storing and preparing the data for other teams
software was mostly written in Python and Go and the pipeline was based on Kafka
lots of data processing, working with storages like Elasticsearch, MongoDB, Redis, PostgreSQL, Bigquery
Bigtable literally saved us couple of times :)
used monitoring stack based on statsd, Prometheus, InfluxDB and Grafana
devops in the GCP Kubernetes stack, lots of namespaces
(oh and, yes i am in love with Go!)

2015 - 2018 Sufio, Python developer (Python, Go)

Privacy Policy

Thu, 09 Jan 2020 02:13:50 +0000

This Privacy Policy describes how your personal information is collected, used, and shared when you visit https://jbub.eu/ (the “Site”).

PERSONAL INFORMATION WE COLLECT

We do not collect any Personal information.

We do not share your Personal Information.

CHANGES

We may update this privacy policy from time to time in order to reflect, for example, changes to our practices or for other operational, legal or regulatory reasons.

CONTACT US

For more information about our privacy practices, if you have questions, or if you would like to make a complaint, please dont hesitate to contact us.

Publishing Go Test Coverage

Sat, 02 Dec 2017 21:55:50 +0000

Lets say you have an open source project called mypkg written in Go programming language and you host the repository over at Github (https://github.com/jbub/mypkg). As a proper Go developer you write tests to make sure you code works and you also measure code coverage over time. Your simple project consists of two subpackages called subpkg1 and subpkg2. The project structure looks roughly like this:

mypkg
├── subpkg1
│   ├── file1.go
│   └── file1_test.go
└── subpkg2
    ├── file2.go
    └── file2_test.go

You write your tests using the great testing package from the standard library. Go provides you with the go test command to run those tests from the command line. In order to measure the test coverage you want to run the command with the -coverprofile flag enabled. This flag defines a path where the test coverage output data will be saved. It can then later be used to visualize or store the coverage data. So lets try to run it:

Pgbouncer Exporter

Sat, 23 Sep 2017 10:25:50 +0000

Install

go get github.com/jbub/pgbouncer_exporter

Docs

https://godoc.org/github.com/jbub/pgbouncer_exporter

Backing up PostgreSQL using WAL-E

Mon, 16 May 2016 10:30:50 +0000

If you are running PostgreSQL database server, you will surely need to do backups at some point. If you already do, you are probably using the pg_dump and pg_restore combo. These commands are good for small to medium sized databases, but not for big ones. Also you can not run pg_dump continuously, so you really can lose the new data if something bad happens between the dumps. Fortunately PostgreSQL is using the technique called Write Ahead Log (WAL) to ensure the integrity of the data. The simple explanation is: for every data change, there has to be a log entry written first and flushed to permanent storage. WAL is a continuous log of changes, which can be used to restore database to consistent state. If you disable fsync, you will no longer have the guarantee that your database can be recovered to the original state before the crash. Now how do we use this WAL to do continuous backups ? PostgreSQL allows us to specify custom command to run for every generated WAL change (archive). While this is great, it is still quite complex to setup continuous archiving by hand.

Standard data types in Python

Mon, 07 Dec 2015 02:13:50 +0000

class: center, middle

Standard data types in Python

https://github.com/jbub/spy-data-types

Agenda

Type system of Python
None
Booleans
Numbers
String
Lists
Tuples
Sets
Dictionaries
Ranges
Iterators and generators
Collections

Type system of Python

Python is strongly typed.

every change of type requires explicit conversion

# this will fail
a = 3 + "45"

Python is dynamically typed.

types are checked at runtime
duck typing

# assign an integer
a = 4
# then change it to string
a = "hello"
# duck
a.lower()

Everything in Python is an object.

Tunnel remote server to your local SSL dev server

Wed, 11 Nov 2015 10:30:50 +0000

In the modern world of web development you will need to consume automatic external calls to your application at some point. These calls will trigger some sort of action in your application and are usually called webhooks. It is very hard to debug these, since you cant really point webhooks to your local development environment. To overcome this we will use SSH tunnel to direct traffic to our local development server.

Tabular

Mon, 25 May 2015 18:08:50 +0000

Install

go get github.com/jbub/tabular

Docs

https://godoc.org/github.com/jbub/tabular

Using Salt Masterless with Fabric

Sat, 02 May 2015 02:13:50 +0000

Sometimes using Salt in master-minion mode is a overkill. Managing a single server can be done in a more simple way. Salt provides masterless mode in which you dont have to use salt master at all.

I keep the server configuration under version control in a git repository. The main Fabric file is located in the project root. Salt states and pillars are stored in the roots directory.

.
├── fabfile.py
├── roots/
│   ├── pillar/
│   │   ├── common.sls
│   │   └── top.sls
│   └── salt/
│       ├── common/
│       └── top.sls
└── templates/
    └── minion

The minion config template is located under the templates directory. It is a Jinja 2 template and we rerender it everytime we apply the configuration to the server. Remember that every Salt operation is running on the remote server and we use Fabric to connect to it.

Ghostwriter

Sun, 26 Apr 2015 02:13:50 +0000

Install

# in your hugo project folder
git clone git@github.com:jbub/ghostwriter.git themes/ghostwriter

# set in your hugo config file
theme = "ghostwriter"

Translations

Fri, 03 Apr 2015 02:13:50 +0000

I am mostly translating open source software projects from English to Slovak language and vice versa.

Twitter

Member of Slovak language community at Twitter Translation Center.

translate.twitter.com/user/jbub_

A Tour of Go

Slovak translator of the Go programming language official tutorial.

go-tour-sk.appspot.com

Transifex

Modern localization workflow and crowdsourcing platform.

Coordinator and translator

Translator

Podcasts

Tue, 18 Nov 2014 02:13:50 +0000

Install

go get github.com/jbub/podcasts

Docs

https://godoc.org/github.com/jbub/podcasts

Banking

Tue, 26 Aug 2014 02:13:50 +0000

Install

go get github.com/jbub/banking

Docs

https://godoc.org/github.com/jbub/banking

Savey

Wed, 14 May 2014 02:13:50 +0000

Install

go get github.com/jbub/savey

Docs

https://godoc.org/github.com/jbub/savey

Git everyday

Wed, 19 Mar 2014 02:13:50 +0000

Adding

Git has a staging area which is area between your working copy and repository. You can add files to the index using git add command. Git adds files with respect to the .gitignore file.

git add .  # adds all files
git add -u # adds deleted files
git add -A # shortcut for both previous steps

Aliases

Git allows us to create shortcuts for frequently used commands in form of aliases.

Django project template

Mon, 20 Jan 2014 02:13:50 +0000

Install

django-admin.py startproject --template=https://github.com/jbub/django-project-template/archive/master.zip project_name

Django suit locale

Wed, 15 Jan 2014 02:13:50 +0000

Install

pip install django-suit-locale

Translate

https://transifex.com/projects/p/django-suit-locale/

Python notes

Wed, 17 Jul 2013 02:13:50 +0000

Lists

# generate matrix n x n
[[col for col in range(n)] for row in range(n)]

# flatten matrix
[num for row in m for num in row]

# generate identity matrix with the size of n
[[1 if col == row else 0 for row in range(n)] for col in range(n)]

# return a random element from the non empty sequence
random.choice([1, 4, 7, 9]) >>> 7

# return a k length list of unique elements chosen from the population sequence
random.sample([1, 2, 3, 4], 2) >>> [4, 1]

# shuffle the sequence t in place
t = [1, 2, 3]
random.shuffle(t)
t >>> [3, 1, 2]

# return a k length string of random characters chosen from the chars string
''.join(random.sample('abcdefg', 4)) >>> 'afge'

Sets

# lists with duplicate items
a = [1, 2, 3]
b = [4, 1, 1, 3, 5]

# notice that there are only unique items in the sets
sa = set(a)
sa >>> set([1, 2, 3])
sb = set(b)
sb >>> set([1, 3, 4, 5])

# return a new set with elements common to the set and all others
sa & sb >>> set([1, 3])

# return a new set with elements from the set and all others
sa | sb >>> set([1, 2, 3, 4, 5])

# return a new set with elements in either the set or other but not both
sa ^ sb >>> set([2, 4, 5])

# return a new set with elements in the set that are not in the others
sa - sb >>> set([2])

Dictionaries

# group a sequence of key-value pairs into a dictionary of sets
s = [('add', 2), ('delete', 3), ('add', 4), ('edit', 10), ('edit', 6)]
things = defaultdict(set)
for action, number in s:
    things[action].add(number)
things >>> defaultdict(<type 'set'>, {'edit': set([10, 6]), 'add': set([2, 4]), 'delete': set([3])})

# create ordered dictionary representing days of month as keys with value equal to 0
OrderedDict.fromkeys(xrange(1, calendar.monthrange(2013, 7)[1] + 1), 0)

Dotfiles

Wed, 03 Jul 2013 02:13:50 +0000

Install

# install from pypi
pip install dotfiles

# clone
git clone git@github.com:jbub/dotfiles.git ~/Dotfiles

# sync all dotfiles
dotfiles --sync --force

Django web deployment notes

Sun, 09 Sep 2012 02:13:50 +0000

Checklist

404, 500 pages
cron cleanup job: manage.py cleanup
set SESSION_COOKIE_AGE
set ADMINS and MANAGERS
DEBUG = False
check and test emails
cache headers
cache static files
set project domain and name in sites application

gzip
expire headers
logs
project_name.conf
include project_name.conf to projects.conf
conf/project_name.conf

analytics, webmaster tools
favicons
robots.txt
sitemap.xml
meta tags and headers

noscript message

Applications

django-tinymce

In order to work with multiple domains or subdomains, following needs to be done.

Linux SSH

Sat, 07 Jul 2012 02:13:50 +0000

Logging without password

The common problem with ssh is to enter your password every time you log in. To automatize this, you can generate a pair of keys and copy the public one to the remote server. This way you can log in without typing password every time.

Generate keys on your local machine

Generate a new pair of keys and save it under /home/user/.ssh/id_rsa. Do not enter any passphrase if you do not want to type it every time you log in.

jbub

About

School

Thesis

Work experience

Privacy Policy

PERSONAL INFORMATION WE COLLECT

SHARING YOUR PERSONAL INFORMATION

CHANGES

CONTACT US

Publishing Go Test Coverage

Pgbouncer Exporter

Install

Docs

Backing up PostgreSQL using WAL-E

Standard data types in Python

Standard data types in Python

Agenda

Type system of Python

Tunnel remote server to your local SSL dev server

Tabular

Install

Docs

Using Salt Masterless with Fabric

Ghostwriter

Install

Translations

Twitter

A Tour of Go

Transifex

Coordinator and translator

Translator

Podcasts

Install

Docs

Banking

Install

Docs

Savey

Install

Docs

Git everyday

Adding

Aliases

Django project template

Install

Django suit locale

Install

Translate

Python notes

Lists

Sets

Dictionaries

Dotfiles

Install

Django web deployment notes

Checklist

Django related

Lighttpd related

Seo related

Website related

Applications

django-tinymce

Linux SSH

Logging without password

Generate keys on your local machine