Przemysław Wróblewski lowang

Tips & Tricks from Docker Captain

Łukasz Lach, Docker Captain | 2022

https://lach.dev/ | https://github.com/lukaszlach/

Docker Masters | http://dockermasters.pl/

Build-time

wildcard DNS in localhost development

install dnsmasq

$ brew install dnsmasq
   ...
$ cp /usr/local/opt/dnsmasq/dnsmasq.conf.example /usr/local/etc/dnsmasq.conf

edit /usr/local/etc/dnsmasq.conf

address=/local/127.0.0.1

The reason why you might get certificate errors in Ruby 2.0 when talking HTTPS is because there isn't a default certificate bundle that OpenSSL (which was used when building Ruby) trusts.

Update: this problem is solved in edge versions of rbenv and RVM.

$ ruby -rnet/https -e "Net::HTTP.get URI('https://github.com')"
net/http.rb:917:in `connect': SSL_connect returned=1 errno=0 state=SSLv3
  read server certificate B: certificate verify failed (OpenSSL::SSL::SSLError)

You can work around the issue by installing a certificate bundle that you trust. I trust Mozilla and curl.

	#!/usr/bin/env ruby
	require "socket"

	# This is a simple preloader for Ruby apps.
	# Usage:
	# Put this file somewhere in your PATH, named 'ruby_preloader' and make sure
	# it's executable.
	# Add whatever you need to load your app environment to a .preload.rb in the
	# base directory of your project.
	# Add #!/usr/bin/env ruby_preload as the first line of any script you want to

	# http://zookeeper.apache.org/doc/r3.3.4/recipes.html#sc_leaderElection
	require 'rubygems'
	require 'bundler/setup'
	require 'zookeeper'
	require 'hashie'

	class ElectionCandidate
	ROOT_PATH = "/election"
	NODE_PATH = "candidate_"

	-- show running queries (pre 9.2)
	SELECT procpid, age(clock_timestamp(), query_start), usename, current_query
	FROM pg_stat_activity
	WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%'
	ORDER BY query_start desc;

	-- show running queries (9.2)
	SELECT pid, age(clock_timestamp(), query_start), usename, query
	FROM pg_stat_activity
	WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'

	#Model

	@user.should have(1).error_on(:username) # Checks whether there is an error in username
	@user.errors[:username].should include("can't be blank") # check for the error message

	#Rendering
	response.should render_template(:index)

	#Redirecting
	response.should redirect_to(movies_path)

	# codec: blocks

	describe('articles.views.ArticleView'):

	context('when user has permissions'):

	it('should add new article'):
	# some code

	it('should delete existing article'):