lukaszlach

Tips & Tricks from Docker Captain

Łukasz Lach, Docker Captain | 2022

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

Docker Masters | http://dockermasters.pl/

Build-time

eloypnd

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

matsadler

#!/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

fabrizioc1

# 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_"

mislav

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.

rgreenjr

-- 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%' 

them0nk

#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)

yumike

# codec: blocks

describe('articles.views.ArticleView'):

    context('when user has permissions'):

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

        it('should delete existing article'):