zmoazeni

% ./force-failure
Building linux binary in build/bin
Building darwin binary in build/bin
# command-line-arguments
clang: warning: argument unused during compilation: '-nopie'
Binaries found in:
build/dist/gh-ost-binary-linux-20190607173922.tar.gz
build/dist/gh-ost-binary-osx-20190607173922.tar.gz
### Building docker image for 5.7.21
Sending build context to Docker daemon  4.608kB

zmoazeni

2019-06-05 23:14:38 INFO starting gh-ost 1.0.48
2019-06-05 23:14:38 INFO Migrating `test`.`gh_ost_test`
2019-06-05 23:14:38 INFO connection validated on 127.0.0.1:5722
2019-06-05 23:14:38 INFO User has ALL privileges
2019-06-05 23:14:38 INFO binary logs validated on 127.0.0.1:5722
2019-06-05 23:14:38 INFO Inspector initiated on f17262bbdece:5722, version 5.7.21-log
2019-06-05 23:14:38 INFO Table found. Engine=InnoDB
2019-06-05 23:14:38 DEBUG Estimated number of rows via STATUS: 2
2019-06-05 23:14:38 DEBUG Validated no foreign keys exist on table
2019-06-05 23:14:38 DEBUG Validated no triggers exist on table

zmoazeni

The main concept of a Test Lock is basically a mutex between the thread running the tests and the thread handling the server requests.

Our main issue had to do with our teardown destroying database records while a request was ongoing. It's extremely tricky to debug because it's entirely timing based. (Request begins, before_actions are happy, teardown begins, records are destroyed, request sometimes freaks out).

So the idea is that once we TestLock.join, we flip a gate that disallows any new requests, and blocks until the existing request is complete. Then we know we can safely purge the database (and other elements).

zmoazeni

module Jekyll
  class VersionedPage < Page
    def initialize(site, base, dir, version, post)
      @site = site
      @base = base
      @dir = dir
      @name = "#{version}/#{post.url}#{post.data["ext"]}"
      process(@name)
      self.content = post.content
      self.data = post.data

zmoazeni

# Application that is upgrading to 4.1.9

{"miles" => 12.45.to_d}.to_json
=> "{\"miles\":12.45}"



# Brand new 4.1.9 application

{"miles" => 12.45.to_d}.to_json

zmoazeni

SomeObj = Struct.new(:foo, :bar, :baz) do
  def initialize(foo:, bar:, baz: 'is optional')
    self.foo = foo
    self.bar = bar
    self.baz = baz
  end
end

p SomeObj.new(foo: 1, bar: 2)
p SomeObj.new(foo: 1, bar: 2, baz: 'overridden')

zmoazeni

∴ cd /tmp/
∴ mkdir testing-hashtables
∴ cd testing-hashtables/
∴ cabal sandbox init
Writing a default package environment file to
/private/tmp/testing-hashtables/cabal.sandbox.config
Creating a new sandbox at /private/tmp/testing-hashtables/.cabal-sandbox
∴ cabal install hashtables
Resolving dependencies...
Notice: installing into a sandbox located at

zmoazeni

cabal exec -- ghci # starts ghci with cabal sandbox set
cabal exec -- runghc ... # runs runghc with cabal sandbox set

zmoazeni

def foo(a, bar: 'something else')
  puts "a: [#{a}], bar: [#{bar}]"
end

some_hash = { :bar => 'passed as a param' }
foo(1, some_hash) # outputs: a: [1], bar: [passed as a param]

zmoazeni

should_i_do_it = false

def foo(bar:, do_it: true)
  puts "bar: [#{bar}] do_it: [#{do_it}]"
end

foo(:bar => 'this be bar', :do_it => should_i_do_it)
foo(bar: 'this be bar', do_it: should_i_do_it)