( °͡ ʖ͜ °͡) .oO(Hi)

Aaron Patterson

Ruby Core Rails Core

Enterprise Software

Twitter: tenderlove

GitHub: tenderlove

Instagram: tenderlove

Yo: tenderlove

apatters@redhat.com

tenderlove@redhat.com

Tender Parents

OMG

INTERNET

POINTS

Revert Commits Count Too!

More mistakes == more points!!!!

Short Stack Engineer

Gorbachev Puff Puff Thunderhorse

SEA-TAC Airport YouTube

I am new!

LostPassport

Very 😴

I am new!

Upgrading to Rails 4.x

Upgrading to Edge Rails

Rails Release Timeline

4.2 is Very Soon™

Next is 5.0

Upgrading Rails

Why?

Performance

Memory Reduction

Cost

How?

Push upstream

Move to gems

Change implementation

Issues Today

Rails Fork

Rails Monkey Patches

Monkey Patches

Rails Fork

Active Record Object Allocation Time

ms = Benchmark.ms do records = rows.map { |model| # … }.uniq end

logger.debug(' %s Inst Including Associations (%.1fms - %drows)' % [join_base.active_record.name || 'SQL', ms, records.length])

We can’t upstream this :-(

ActiveSupport Notifications

ActiveSupport::Notifications.instrument( "some.key", payload ) do records = rows.map { |model| # ... }.uniq end

ActiveSupport::Notifications.subscribe('some.key' ) do |value| # same logger statement end

Truncate table

# Executes the truncate statement. def truncate(table_name, name = nil) execute("TRUNCATE TABLE #{quote_table_name(table_name)}", name) end

Pushed up stream

Added a monkey patch to backport

64 bit primary keys

In PG: "integer" == 32bit

In PG: "bigint" == 64bit

Default is 32bit

Why?

¯\_(ツ)_/¯

Schema.rb

create_table "accounts" do |t| t.string "name" t.integer "acctid" end

No PK

declared

Means32bit

We can upstream this

Determine backwards compat scheme

Default PK sequences

+ return if options[:id] == false + return unless self.respond_to?(:set_pk_sequence!) + + value = ActiveRecord::Base.rails_sequence_start + set_pk_sequence!(table_name, value) unless value == 0

We can’t upstream this

Extract and "super"

Add "extension" points.

Auto-reconnect

Supposedly fixed?

+ def self.did_retry_db_connection(connection,count) + logger.info "CONNECTION RETRY: #{connection.class.name} retry ##{count}." if logger + end

Push Up Better Exceptions

Connection Extensions

Database Statistics

Create a new gem: activerecord-pg-stats

Virtual Columns

Declaration

virtual_column :name, :type => :string

2 Responsibilities

Declare a "column type" for reporting

Declare associations used by the method

Separate these concerns

Extract reporting

Push up relation declaration.

RJS

Land the Angular patch!!!!

jquery-rjs

prototype-rails

Monkey Patches

First Glance

Churn

"How often is stuff changing?"

git log --all -M -C --name-only --format='format:' "$@" | sort | grep -v '^$' | uniq -c | sort -n | awk 'BEGIN {print "count\tfile"} {print $1 "\t" $2}'

445 vmdb/app/models/miq_server.rb 498 vmdb/app/models/miq_provision_workflow.rb 508 vmdb/app/models/miq_provision.rb 590 vmdb/app/models/miq_report.rb 720 vmdb/app/controllers/report_controller.rb 777 vmdb/app/models/vm.rb 802 vmdb/app/models/host.rb 825 vmdb/app/helpers/application_helper.rb 1186 vmdb/app/controllers/application.rb

Cyclomatic Complexity

Quantify Code Complexity

flog

1965.9: vmdb/db/migrate/20100302205959_collapsed_initial_migration.rb:7 1131.5: vmdb/app/controllers/ops_controller/settings/common.rb:621 1024.9: vmdb/app/controllers/application_controller/filter.rb:137 951.9: vmdb/app/controllers/application_controller/performance.rb:220 862.9: vmdb/spec/models/ems_refresh/refreshers/vc_refresher_spec.rb:27 842.8: vmdb/app/controllers/ops_controller/settings/common.rb:881 824.5: vmdb/spec/models/ems_refresh/refreshers/rhevm_refresher_3_1_spec.rb:230 791.5: vmdb/app/helpers/application_helper.rb:648

application_helper $$$$$$

Static Analysis

Find unused methods

Ripper

require 'ripper'

class MyParser < Ripper def on_def name, _, _ # do something end end

parser = MyParser.new "some code" parser.parse

class MyParser < Ripper attr_reader :methods, :calls

def initialize code, file, line super @methods = [] @calls = [] end

def on_def name, *rest @methods << name end alias :on_command :on_def

def on_defs target, dot, name, *args @methods << name end

def on_call target, dot, name @calls << name end

def on_fcall name @calls << name end alias :on_symbol :on_fcall alias :on_vcall :on_fcall end

Find.find(ARGV[0]) do |file| next if File.directory? file ext = file[/(?<=\.)\w+$/] next unless ext case ext when 'rb' parser = MyParser.new(File.read(file), file, 1) parser.parse when 'erb' parser = MyParser.new ERB.new(File.read(file)).src, file, 1 parser.parse end end

Dynamic Dispatch

superclass.send("virtual_#{m}")

Static Analysis + Ruby = 😰

Probably also why Brakeman isn’t perfect

This Summit is GREAT!

Communication

Browser

WebServer

Memcached

Every 500msBrowser

WebServer

Memcached

Every 500msBrowser

WebServer

Memcached

Cache Size

Code Complexity

Bugs

Server Load

Every 500msBrowser

WebServer

Memcached

Always Question Assumptions

Ask Why

Business Requirements aren’t set in stone.

Thanks Everyone!

Questions?