januszm

# as root or with sudo

swapoff -a
sysctl -w vm.swappiness=1
sysctl -w fs.file-max=262144
sysctl -w vm.max_map_count=262144

yum install https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm
yum install mysql-devel redis-devel
amazon-linux-extras install redis4.0

januszm

# env - run a program in a modified environment
# envirotnment is read from crontab file, usually it's below and nothing else:
# SHELL=/bin/sh
# PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
env - `cat /etc/crontab | grep -v "#" | grep -v "^$" | grep -v /etc/cron` my_script.sh

januszm

januszm

sudo apt-get update
sudo apt-get install build-essential git libreadline-dev zlib1g-dev libssl-dev libbz2-dev libsqlite3-dev
curl -L https://github.com/pyenv/pyenv-installer/raw/master/bin/pyenv-installer | bash
# may need this, but install script above should handle it; and yeah, you can do multiline inserts with awk/sed or whatever
echo 'export PATH="/root/.pyenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.bashrc
source ~/.bashrc
pyenv install 3.6.0

januszm

sudo amazon-linux-extras install postgresql12
pg_dump -Fc -O -h yyy-production.xxx.region.rds.amazonaws.com -p 5432 -U yyy yyy_production -f yyy.dump
# TRUNCATE TABLE tables ... RESTART IDENTITY
# rails db:migrate
pg_restore -Fc -O --disable-triggers --data-only -h yyy-staging.xxx.region.rds.amazonaws.com -d yyy_staging -U yyy yyy.dump
# both commands accept the --table option to specify which table to dump/restore
# select setval('TABLE_NAME_id_seq', (select max(id) from TABLE_NAME)); may be required after RESTART IDENTITY, +1

# In case of version mismatch between the server and pg_dump, add pgdgXX repo and install XX client
[pgdg14]

januszm

import traceback; [line for line in traceback.format_stack() if not 'site-packages' in line]

januszm

# alternatively use benchmark/ips

n = 100_000
data = "..."

Benchmark.ips do |benchmark|
  benchmark.report("include?") do
    n.times { data.to_s.downcase.include?('windows') }
  end
  benchmark.report("match?") do

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# Have you ever had to sleep() in Capybara-WebKit to wait for AJAX and/or CSS animations?

describe 'Modal' do
  
  should 'display login errors' do
    visit root_path
    click_link 'My HomeMarks'
    within '#login_area' do
      fill_in 'email', with: '[email protected]'
      fill_in 'password', with: 'test'

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[database]
log_queries = true

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result = ActiveRecord::Base.connection.execute("select * from my_shapes_table limit 1;")
shape = parser.parse result.values.first.last # .first row , .last column
RGeo::GeoJSON.encode(shape).to_json
# => "{\"type\":\"MultiPolygon\",\"coordinates\":[[[[...]]]]}"