Abstracting Services In Ruby C0 Coverage Information - RCov

 # !SLIDE

 # Abstracting Services in Ruby

 #

 # * Kurt Stephens

 # * Enova Financial

 # * 2012/01/25

 # * Slides -- "":http://kurtstephens.com/pub/ruby/abstracting_services_in_ruby/asir.slides/

 # * Code -- "":http://kurtstephens.com/pub/ruby/abstracting_services_in_ruby/

 # * Git -- "":http://github.com/kstephens/abstracting_services_in_ruby

 # * Tools

 # ** Riterate -- "":http://github.com/kstephens/riterate

 # ** Scarlet -- "":http://github.com/kstephens/scarlet

 #

 # !SLIDE END

 # !SLIDE

 # Issues

 #

 # * Problem Domain, Solution Domain

 # * Service Middleware Semantics

 # * Testing, Debugging, Diagnostics

 # * Productivity

 #

 # !SLIDE END

 # !SLIDE

 # Problem Domain, Solution Domain

 #

 # * Client knows too much about infrastructure.

 # * Evaluating and switching infrastructures.

 #

 # !SLIDE END

 # !SLIDE

 # Service Middleware Semantics

 #

 # * Directionality: One-way, Two-way

 # * Synchronicity: Synchronous, Asynchronous, Delayed, Buffered

 # * Distribution: Local Thread, Local Process, Distributed

 # * Transport: File, IPC, Pipe, Network

 # * Robustness: Retry, Replay, Fallback

 # * Encoding: XML, JSON, YAML, Base64, Compression

 #

 # !SLIDE END

 # !SLIDE

 # Testing, Debugging, Diagnostics

 #

 # * Configuration for testing and QA is more complex.

 # * Measuring test coverage of remote services.

 # * Debugging the root cause of remote service errors.

 # * Diagnostic hooks.

 #

 # !SLIDE END

 # !SLIDE

 # Objectives

 #

 # * Simplify service/client definitions and interfaces.

 # * Anticipate new encoding, delivery and security requirements.

 # * Separate encoding and transport concerns.

 # * Composition over Configuration.

 # * Elide deployment decisions.

 # * Integrate diagnostics and logging.

 # * Simplify testing.

 #

 # !SLIDE END

 # !SLIDE

 # Foundations of Objects

 #

 # * Message

 # * State

 # * Behavior

 # !SLIDE

 # Messaging

 #

 # * "Call a Method", "Call a Function" are all the same, in *all* languages.

 # ** Decomposed lookup() and apply().

 # * "Send Message", not "Call a Method".

 # * Messaging abstracts:

 # ** Object use from its implemenation.

 # ** Transfer of control (method, function invocation).

 # !SLIDE

 # REST

 #

 # "Roy Fielding - Architectural Styles and the Design of Network-based Software Architectures":http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm

 #

 # * Imperative Action .vs. Behavorial Resource

 # * REST Connector .vs. REST Component

 #

 # !SLIDE END

 # !SLIDE

 # Design

 #

 # * Nouns -> Objects -> Classes

 # * Verbs -> Responsibilities -> Methods

 #

 # h3. Book: "Designing Object-Oriented Software"

 #  * Wirfs-Brock, Wilkerson, Wiener

 #

 # !SLIDE END

 # !SLIDE

 # Design: Nouns

 #

 # * Service -> Module

 # * Client -> Just a Ruby caller

 # * Proxy

 # * Request -> Just a method call.

 # * Response, Exception (two-way) -> Return value or else.

 # * Transport -> (file, pipe, http, queue, ActiveResource)

 # * Encoder, Decoder -> Coder (Marshal, XML, JSON, ActiveResource)

 # * Logging

 #

 # !SLIDE END

 # !SLIDE

 # Design: Verbs

 #

 # * Intercept Request -> Proxy

 # * Invoke Request    -> Request

 # * Invoke Exception

 # * Send Request, Recieve Request -> Transport

 # * Encode Object, Decode Object -> Coder

 #

 # !SLIDE END

 # !SLIDE

 # Simple

 #

 # !PIC BEGIN

 # 

 # box "Client" "(CustomersController" "#send_invoice)"; arrow; 

 # ellipse "Send" "Request" "(Ruby message)"; arrow; 

 # box "Service" "(Email.send_email)";

 #

 # !PIC END

 #

 # !SLIDE END

 # !SLIDE

 # Client-Side Request

 #

 # !PIC BEGIN

 # box "Client"; arrow; 

 # ellipse "Proxy"; arrow; 

 # ellipse "Create" "Request"; arrow; 

 # ellipse "Encode" "Request"; arrow; 

 # ellipse "Send" "Request";

 # line; down; arrow;

 # !PIC END

 #

 # !SLIDE END

 # !SLIDE

 # Server-Side

 #

 # !PIC BEGIN

 # down; line; right; arrow; 

 # ellipse "Receive" "Request"; arrow; 

 # ellipse "Decode" "Request"; arrow; 

 # ellipse "Request"; 

 # line; down; arrow; 

 # IR: ellipse "Invoke" "Request";

 # right; move; move;

 # Service: box "Service" with .w at IR.e + (movewid, 0); 

 # arrow <-> from IR.e to Service.w;

 # move to IR.s; down; line;

 # left; arrow; 

 # ellipse "Create" "Response"; arrow; 

 # ellipse "Encode" "Response"; arrow;

 # ellipse "Send" "Response"; 

 # line; down; arrow

 # !PIC END

 #

 # !SLIDE END

 # !SLIDE

 # Client-Side Response

 #

 # !PIC BEGIN

 # down; line; left; arrow;

 # ellipse "Receive" "Response"; arrow; 

 # ellipse "Decode" "Response"; arrow; 

 # ellipse "Response"; arrow; 

 # ellipse "Proxy"; arrow; 

 # box "Client";

 # !PIC END

 #

 # !SLIDE END

 # !SLIDE

 # Implementation

 #

 # * Primary Base classes: Transport, Coder

 # * Primary API: Proxy via Client mixix

 # * Handful of mixins.

 #

 # !SLIDE

 # Modules and Classes

   # Reusable constants to avoid unnecessary garbage.

 end

 # !SLIDE END

 # !SLIDE

 # Synopsis

 #

 # * Services are easy to abstract away.

 # * Separation of transport, encoding.

 #

 # !SLIDE END

 #

 # !SLIDE

 # Appendix

 #

 #

 # !SLIDE END