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Author: Eduardo Lezcano

Engineer, developer and creator

Simply curious

Docker source hardcoded to the docker hub

I just needed to complain about this.

Docker, the beloved containerdization tool is not as open as they claim it to be. The main source of containers is hardcoded in the tool to point towards the docker hub, and that site is now converting to a market place

Is the first time I see a package management system that forces you to use a specific source and I’m not happy with the decission.

I have my own registry and I want to use it as my default!

5 reasons why you should learn Make

Maybe you have feel from time to time the speed of the current technology development. Maybe you have taken decisions like “I will choose the latest technology for my new project”. And maybe in the middle of the development you realized your decisions delay you because the new technologies you have chosen are… Well, new.

I always had curiosity for old and reliable technologies so when I started years ago with Linux and software automation I decided to learn Make. I, as many persons, saw at make as a dark voodoo magic that was used all over the place to build C programs, but then I start reading the manual. It wasn’t an easy choice. Big manual, lots of work to do, deadlines… But I did it. And now I can say I know Make and I have a super-tool for automation. I even had published a condensed cheatsheet that I use every day I need to work in makefiles.

I want to share with you why I think you need to pay attention to this amazing tool right now and if you find it interesting check out the introduction I’m writing.

1.- Is standard

It conforms to section 6.2 of IEEE Standard 1003.2-1992 (POSIX.2). So the basics are there for you, don’t matter where you execute your makefiles. Particularly useful is the GNU version of make where some clever features have been added though.

It always goes straight to the point.
No surprises.
No random failures.
No dependencies.
No additional requirements.

2.- Is compact and clean

Only two types of statements: Variable assignments and rules. Additionally rules are written as recipes, those you follow at home preparing a nice rissotto.

VARIABLE := value

dish: ingredient1 ingredient2 ingredient3

But take a look to the real thing and try to get the pattern. It doesn’t look that complex, isn’t it?

PYTHON_EXEC             := python3
DEVPI_SERVER_ADDRESS    := localhost:3141

python.release: python.check
    $(PYTHON_EXEC) sdist
    devpi use $(DEVPI_SERVER_ADDRESS)
    devpi login admin --password admin1234
    devpi use root\/dev
    devpi upload dist/$(PROJECT_NAME)-$(PROJECT_VERSION).tar.gz
    devpi logoff

3.- Is smart

If you write your makefiles properly Make will always perform the minimum amount of operations to achieve any goal. As it checks timestamps of files you have generated if the files you are generating are older than the ingredient files then Make will not do anything for that file.

4.- Is insanely fast

Parsing of all recipes and variables takes no time. Is that fast that in Linux you can use Shell auto-completion instantaneously. And believe me: if you have thousands of files this makes your life much easier.

me@mypc:~/test_folder                                       git master
$ cat Makefile
TARGETS:= $(wildcard *.txt)

        echo '$@'
me@mypc:~/test_folder                                       git master
$ make test {{TAB TAB}}
test01.txt  test03.txt  test05.txt  test07.txt  test09.txt  test11.txt
test13.txt  test15.txt  test17.txt  test19.txt  test21.txt  test23.txt 
test25.txt  test27.txt  test29.txt  test02.txt  test04.txt  test06.txt 
test08.txt  test10.txt  test12.txt  test14.txt  test16.txt  test18.txt
test20.txt  test22.txt  test24.txt  test26.txt  test28.txt  test30.txt
me@mypc:~/test_folder                                       git master
$ make test

Learn how to get this awesome 2 line prompt with SVC integration

5.- It will surprise you every day

Since I started using Make there is no day where I realize of cleaver features that has been embedded on it that can be used to automate any process. Sometimes when I realize some feature will be very useful I just look into the manual and is already implemented for me to use! No other language I ever used achieved that level of convenience for me before.

In conclusion Make for me is a really powerful tool that has been a bit undervalued by young developers (I think due to it’s apparent initial time investment). But when you get to know it and you’ll see that rapidly pays of the investment.

Make is a beautiful tool.

A Tour of Go: Web Crawler

After playing with Go a couple of days I managed to finish the tour. Actually I learned a bit more reading related articles and linked pages. I really recommend the experience as an initial attempt to understand go.

As a last exercise you are requested to program a simple web crawler. Find the code at the end of this post (I will not be much longer).
After a couple of hours tinkering and recalling all the knowledge from the language I managed to complete the exercise. Many things of this new language to interiorize.

No big conclusions yet about Go, but what I’m pretty sure is how good it enforces recursion and concurrency in programs…

Try this code on the Go Playground