Recently I came across nice explanation and illustration of most common design patterns. If you would like to learn or familiarize yourself with design patterns then start from here.
Cheers.
Category: Software
Прощай Jabber
На этих выходных я выключил свой личный Jabber сервер! Он служил многие годы верой и правдой, но пришло время сказать “пока” и вырвать штекер.
Я не помню историю протокола и зачем все это было нужно, но в один прекрасный момент большие компании (например: Apple, Google) решили им пользоваться. И даже voip компании дышали не ровно в сторону XMPP. Но, видимо, ему не суждено было остаться.
Apple сделал iMessages, Google сделал hangout, пришёл Twitter и люди двинули к другим “зелёным” полям. Забавно, я помню когда ICQ стал не актуальным… “…и вот новый поворот…” и Jabber свернул туда же.
В душе я знаю, что скорее всего Jabber не вымрет – где-то в пыльном, темном углу заброшенного дома, в белой оцарапанной металической коробке, с визжащим вентилятором и хрустящим жестким диском, на старой не пропатченной операционной системе, будет стоять Jabber сервер и по ночам будет общаться с darknet-ом.
DD-WRT Ad-blocking
Today I decided to re-configure DNS on my DD-WRT powered TP-Link router. While doing so I came across useful ad-blocking script for DD-WRT and decided to share it: DD-WRT Ad-Blocking
Enjoy!
Hammock Driven Development
Recently I came across an interesting philosophy and would like to share it:
A lot of times we (as developers) work on delivering features, however behind every feature is underlying problem to be solved. Why not take time and think it out?
Anyways enjoy the video, I hope it will prove to be useful.
Book reference: How to solve it
Introduction to Object Oriented Patterns [Presentation]
Some time ago I’ve done small presentation: “Introduction to Object Oriented Patterns” and totally forgot about it. Today I found it and decided to publish it, just in case someone finds it useful!!!
If you have any question or suggestions, please let me know.
Cheerz.
Стратегии для тестирования
Пару дней назад нашел отличный слайдшоу на тему тестирования микро-сервисов. Прочитав я воодушевился и советую всем кому интересно прочитать.
Успехов и хорошего тестирования.
Transformation Priority Premise
Не так давно я нашел довольно интересное видео о Transformation Priority Premise. Всем кто занимается/интересуется программированием смотреть!
Как настроить запись и прямое вещание для подкаста под OSX
Сегодня я решил посмотреть как настроить запись и прямой эфир подкаст с Audio HiJack.
Мои требования довольно простые:
– Вещать через Google Hangout или любой другой сервис
– Записывать аудио файл
– Держать скайп в готовности для гостей – возможность прийти в эфир в любой момент!
Тут нужно отметить что все описанные ниже настройки это абсолютный минимум и вы можете сами докрутить эффекты и приделать дополнительные повороты по вашим нуждам.
Необходимый софт:
– Audio HiJack 3
– Soundflower
Скачиваем и ставим. Далее открываем HiJack 3 и создаем новую чистую сессию. Теперь смотрим на картинку ниже и выстраиваем точную копию диаграммы.
Далее можно включить Google Hangout или любой другой стрименговый сервис и указываем как input устройство Soundflower 2ch. Вот и все готово! Теперь нажав запись вы начинаете писать и вещать! Skype канал и микрофон сводятся после обработки ( можно так же добавить фильтры и эффекты ) и даже если скайп звонок отваливается то запись продолжается!
Performance analysis of Atlassian Stash
This article is dedicated to performance estimations and analysis of Atlassian Stash. Recently, I encountered performance issues with Stash – got the following banner on top of the website: “Atlassian Stash is reaching resource limits” and that, prompted questions about performance and possible solutions.
Note:
After initial log reviews, it was established that there are no issues or errors that might prevent Stash from optimal operation. In case of crashes or other issues with Stash, this article will not be helpful.
Data & Performance:
First get access to Stash’s access logs. Please note that log files might be broken into multiple parts so make sure to get them all. Example:
• atlassian-stash-access-2014-04-29.0.log
• atlassian-stash-access-2014-04-29.1.log
Next get “stash-log-parser” – https://bitbucket.org/ssaasen/stash-log-parser. It will go through logs and extract all the relevant information and as a bonus it can make a few very useful graphs.
Once you run the parser and get results, you can quickly review graphs and estimate where and when issues occur. Perhaps you have “automated building tools” that like to clone repos right in the middle of a workday and therefore are straining the server’s resources to the max.
Next you will have to make a rough estimate of your usage and make sure that your machine has enough “juice” to pull the workload. First familiarize yourself with Stash’s “appetite”: https://confluence.atlassian.com/display/STASH/Scaling+Stash
Essentially rough estimates will come out to the following:
CPU requirements: number of CPUs = number of concurrent clone operations / 2
RAM requirements: amount of memory = 1.5 * number of concurrent clone operations * average repository size (if repository is larger than 700MB, then use 700MB for above calculation).
There are other GIT operations (besides clone), but clone is the most demanding one and therefore approximate system requirements are measured via “it”. So let’s take a look at the following examples:
Assume that you have a small setup with an average of 2 concurrent clones and repository sizes of about 5 MB, therefore you will need one CPU core and about 15MB of memory. Another case: you have around 10 concurrent clone requests with repository size of 2GB, therefore you will have to have CPU with at least 5 cores, and about 10.5GB of RAM.
Please note: that Stash itself doesn’t use the entire memory; instead it delegates GIT work to underlying GIT client that is installed in the operating system. Therefore you native GIT client will perform heavy lifting, allocating and de-allocating memory accordingly.
One more piece of advice with memory estimation – try to take an average size of actively used repositories. Stash might host several hundred repos, however active repositories might number only one hundred. In that case it would make sense to measure the average size of only active repos and calculate memory requirements based on that.
Also I would strongly encourage log accumulation (sometimes logs are not kept for more than a week) – that would allow having usage data for longer periods of time and therefore more accurately reflect usage and future needs.
Solutions:
There are a number of solutions that can be employed, in order to reduce workload and improve performance, however performance largely depends on a particular setup and usage scenario. Here are a couple of solutions:
1. Use SCM Cache Plugin in order to reduce cloning load on Stash (https://confluence.atlassian.com/display/STASH/Scaling+Stash)
2. Configure automatic build tools to use HTTP/HTTPS protocol
3. Configure hooks in Stash in order to notify automatic build tools of changes, instead of having automatic build tools pull data on a schedule – reducing number of requests
4. Re-schedule automatic build tools to run off peak hours
5. Upgrade hardware to estimated requirements
Менаджмент софтваре разработок
Случайно наткнулся на статью о менаджменте софтваре разработок от Лайнуса Торвольдса и скажу прямо – она мне понравилась. Всем кому интересная эта тема советую прочитать: Linus Torvalds’s Lessons on Software Development Management
PDF версия: Linus Torvalds’s Lessons on Software Development M…