Class: Fly::Configuration

Inherits:
Object
  • Object
show all
Defined in:
lib/fly-ruby/configuration.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Configuration

Returns a new instance of Configuration.



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# File 'lib/fly-ruby/configuration.rb', line 36

def initialize
  self.primary_region = ENV["PRIMARY_REGION"]
  self.current_region = ENV["FLY_REGION"]
  self.replay_http_methods = ["POST", "PUT", "PATCH", "DELETE"]
  self.database_url_env_var = "DATABASE_URL"
  self.redis_url_env_var = "REDIS_URL"
  self.database_host_env_var = "DATABASE_HOST"
  self.database_port_env_var = "DATABASE_PORT"
  self.replay_threshold_cookie = "fly-replay-threshold"
  self.replay_threshold_in_seconds = 5
  self.database_url = ENV[database_url_env_var]
  self.redis_url = ENV[redis_url_env_var]
  self.replayable_exceptions = ["SQLite3::CantOpenException", "PG::ReadOnlySqlTransaction"]
end

Instance Attribute Details

#current_region ⇒ Object

Set the region where this instance of the application is deployed



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# File 'lib/fly-ruby/configuration.rb', line 6

def current_region
  @current_region
end

#database_host_env_var ⇒ Object

Returns the value of attribute database_host_env_var.



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# File 'lib/fly-ruby/configuration.rb', line 18

def database_host_env_var
  @database_host_env_var
end

#database_port_env_var ⇒ Object

Returns the value of attribute database_port_env_var.



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# File 'lib/fly-ruby/configuration.rb', line 19

def database_port_env_var
  @database_port_env_var
end

#database_url ⇒ Object

Returns the value of attribute database_url.



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# File 'lib/fly-ruby/configuration.rb', line 30

def database_url
  @database_url
end

#database_url_env_var ⇒ Object

Environment variables related to the database connection. These get by this middleware in secondary regions, so they must be interpolated rather than defined directly in the configuration.



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# File 'lib/fly-ruby/configuration.rb', line 17

def database_url_env_var
  @database_url_env_var
end

#primary_region ⇒ Object

Set the region where the primary database lives, i.e “ams”



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# File 'lib/fly-ruby/configuration.rb', line 9

def primary_region
  @primary_region
end

#redis_url ⇒ Object

Returns the value of attribute redis_url.



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# File 'lib/fly-ruby/configuration.rb', line 31

def redis_url
  @redis_url
end

#redis_url_env_var ⇒ Object

Returns the value of attribute redis_url_env_var.



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# File 'lib/fly-ruby/configuration.rb', line 20

def redis_url_env_var
  @redis_url_env_var
end

#replay_http_methods ⇒ Object

Automatically replay these HTTP methods in the primary region



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# File 'lib/fly-ruby/configuration.rb', line 12

def replay_http_methods
  @replay_http_methods
end

#replay_threshold_cookie ⇒ Object

Cookie written and read by this middleware storing a UNIX timestamp. Requests arriving before this timestamp will be replayed in the primary region.



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# File 'lib/fly-ruby/configuration.rb', line 24

def replay_threshold_cookie
  @replay_threshold_cookie
end

#replay_threshold_in_seconds ⇒ Object

How long, in seconds, should all requests from the same client be replayed in the primary region after a successful write replay



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# File 'lib/fly-ruby/configuration.rb', line 28

def replay_threshold_in_seconds
  @replay_threshold_in_seconds
end

#replayable_exceptions ⇒ Object

An array of string representations of exceptions that should trigger a replay



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# File 'lib/fly-ruby/configuration.rb', line 34

def replayable_exceptions
  @replayable_exceptions
end

Instance Method Details

#console? ⇒ Boolean

Is the current process a Rails console?

Returns:

  • (Boolean) 


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# File 'lib/fly-ruby/configuration.rb', line 130

def console?
  defined?(::Rails::Console) && $stdout.isatty && $stdin.isatty
end

#database_app_name ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 67

def database_app_name
  database_uri.hostname.split(".")[-2] || database_uri.hostname
end

#database_domain ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 71

def database_domain
  "#{database_app_name}.internal"
end

#database_uri ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 63

def database_uri
  @database_uri ||= URI.parse(database_url)
end

#eligible_for_activation? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fly-ruby/configuration.rb', line 115

def eligible_for_activation?
  database_url && primary_region && current_region && !rake_task?
end

#hijack_database_connection! ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 119

def hijack_database_connection!
  # Don't reset the database URL for on-disk sqlite
  return if database_uri.scheme.start_with?("sqlite") || database_uri.host !~ /(internal|localhost)/
  ENV["DATABASE_URL"] = in_secondary_region? ? secondary_database_url : primary_database_url
end

#in_secondary_region? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fly-ruby/configuration.rb', line 125

def in_secondary_region?
  primary_region && primary_region != current_region
end

#module_exists?(module_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fly-ruby/configuration.rb', line 56

def module_exists?(module_name)
  mod = Module.const_get(module_name)
  return mod
rescue NameError
  nil
end

#primary_database_url ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 75

def primary_database_url
  uri = database_uri.dup
  uri.host = "#{primary_region}.#{database_domain}"
  uri.port = secondary_database_port
  uri.to_s
end

#rake_task? ⇒ Boolean

Is the current process a rake task?

Returns:

  • (Boolean) 


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# File 'lib/fly-ruby/configuration.rb', line 135

def rake_task?
  defined?(::Rake) && !Rake.application.top_level_tasks.empty?
end

#redis_uri ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 100

def redis_uri
  @redis_uri ||= URI.parse(redis_url)
  @redis_uri
end

#regional_redis_host ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 105

def regional_redis_host
  "#{current_region}.#{redis_uri.hostname}"
end

#regional_redis_url ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 109

def regional_redis_url
  uri = redis_uri.dup
  uri.host = regional_redis_host
  uri.to_s
end

#replayable_exception_classes ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 51

def replayable_exception_classes
  @replayable_exception_classes ||= replayable_exceptions.collect {|ex| module_exists?(ex) }.compact
  @replayable_exception_classes
end

#secondary_database_port ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 89

def secondary_database_port
  port = if in_secondary_region?
    case database_uri.scheme
    when "postgres"
      5433
    end
  end

  port || database_uri.port
end

#secondary_database_url ⇒ Object 



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# File 'lib/fly-ruby/configuration.rb', line 82

def secondary_database_url
  uri = database_uri.dup
  uri.host = "top1.nearest.of.#{database_domain}"
  uri.port = secondary_database_port
  uri.to_s
end

#web? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fly-ruby/configuration.rb', line 139

def web?
  !console? && !rake_task?
end