Function Properties

Important: These docs are for the outdated Jets 5 versions and below. For the latest Jets docs: docs.rubyonjets.com

Jets ultimately translate Ruby code into Lambda functions. Each Lambda function’s properties can be controlled with Jets. Here are the ways to set the function properties and their order of precedence:

1. function specific properties - highest precedence
2. class-wide function properties
3. global function properties set - lowest precedence

Function Specific Properties

Specific function properties are set right above the method definition like so:

class HardJob < ApplicationJob
  timeout 18 # function specific property for the index lambda function
  def dig
    puts "dig"
  end
end

Class-wide Function Properties

Class-wide function properties set in the same class file and with a prefix of class_.

class HardJob < ApplicationJob
  class_timeout 22
  timeout 18 # function specific property for the index lambda function
  def dig
    puts "dig"
  end

  def lift
    puts "lift"
  end
end

For the code above, the new method will have a function timeout of 22 seconds and the index method will have a function timeout of 18 seconds.

Global Function Properties

To set function properties globally, edit the function key under the config object in:

config/application.rb:

Jets.application.configure do
  ...
  config.function.timeout = 30
  # config.function.role = "arn:aws:iam::#{ENV['AWS_ACCOUNT_ID']}:role/service-role/pre-created"
  # config.function.memory_size = 3008
  # config.function.cors = true
  config.function.environment = {
    global_app_key1: "global_app_value1",
    global_app_key2: "global_app_value2",
  }
end

Controllers vs Jobs

You only have fine-grain control of function properties for Jobs, not Controllers. This is because each Job method is deployed as a separate discrete Lambda Function. Whereas, a single Lambda Function is deployed for all controllers.

Function Properties Method

In the above example, we use the timeout and class_timeout method to set function properties. These convenience methods delegate to the more general properties and class_properties methods respectively. The general methods also allow you to change any property for the lambda function. So you could have done this also:

class HardJob < ApplicationJob
  class_properties(timeout: 22)
  properties(timeout: 18) # function specific property for the index lambda function
  def dig
    puts "dig"
  end
end

Generally all the properties associated with Lambda functions have equivalent convenience methods. Here’s a list:

Refer to the AWS::Lambda::Function CloudFormation docs for a list of the properties. You can also refer to the source code itself: lambda/dsl.rb