RESTLess Design with Apache Thrift: Experiences from Apache Airavata

Chathuri Wimalasena, Suresh Marru - Apache Airavata

(Slide Contributions) Randy Abernethy - Apache Thrift

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* Image Source: hHp://blog.law.cornell.edu/voxpop/files/2012/05/VOX.Chicken.Crossing_FreeBeer.jpg

Outline �  Introduction

�  Apache Thrift �  Apache Airavata

� Motivation for Airavata to explore Thrift � Airavata API � Road to Airavata 1.0 � Airavata Thrift based architecture � Experience & lessons learned � Discussion, Q & A

� Modern distributed applications are rarely composed of modules wriHen in a single language

� Weaving together innovations made in a range of languages is a core competency of successful enterprises

� Cross language communications are a necessity, not a luxury

Polyglotism

** Figure source: The Programmer’s Guide to Apache Thrift, Manning Publications Co. * Slide source: Randy Abernethy.

�  A high performance, scalable cross language serialization and RPC framework �  What?

�  Full RPC Implementation -‐‑ Apache Thrift supplies a complete RPC solution: clients, servers, everything but your business logic

�  Modularity -‐‑ Apache Thrift supports plug-‐‑in serialization protocols: binary, compact, json, or build your own

�  Multiple End Points – Plug-‐‑in transports for network, disk and memory end points, making Thrift easy to integrate with other communications and storage solutions like AMQP messaging and HDFS

�  Performance -‐‑ Apache Thrift is fast and efficient, solutions for minimal parsing overhead and minimal size

�  Reach -‐‑ Apache Thrift supports a wide range of languages and platforms: Linux, OSX, Windows, Embedded Systems, Mobile, Browser, C++, Go, PHP, Erlang, Haskell, Ruby, Node.js, C#, Java, C, OCaml, ObjectiveC, D, Perl, Python, SmallTalk, …

�  Flexibility -‐‑ Apache Thrift supports interface evolution, that is to say, CI environments can roll new interface features incrementally without breaking existing infrastructure.

Apache Thrift

* Slide source: Randy Abernethy.

1.  Define the service interface in IDL 2.  Compile the IDL to generate client/server RPC stubs in the desired

languages 3.  Call the remote functions as if they were local using the client stubs 4.  Connect the server stubs to the desired implementation 5.  Choose a prebuilt Apache Thrift server to host your service

thrift IDL

�  Streaming – Communications characterized by an ongoing flow of bytes from a server to one or more clients. �  Example: An internet radio broadcast where the client

receives bytes over time transmiHed by the server in an ongoing sequence of small packets.

�  Messaging – Message passing involves one way asynchronous, often queued, communications, producing loosely coupled systems. �  Example: Sending an email message where you may get a

response or you may not, and if you do get a response you don’t know exactly when you will get it.

�  RPC – Remote Procedure Call systems allow function calls to be made between processes on different computers. �  Example: An iPhone app calling a service on the Internet

which returns the weather forecast.

Comm schemes Apache Thrift is an efficient cross platform

serialization solution for streaming interfaces

Apache Thrift provides a complete RPC framework


�  User Code �  client code calls RPC methods and/or [de]serializes objects

�  service handlers implement RPC service behavior

�  Generated Code �  RPC stubs supply client side proxies and server side processors

�  type serialization code provides serialization for IDL defined types

�  Library Code �  servers host user defined services, managing connections and concurrency

�  protocols perform serialization �  transports move bytes from here to there

Architecture


� The Thrift framework was originally developed at Facebook and released as open source in 2007. The project became an Apache Software Foundation incubator project in 2008, after which four early versions were released.

�  0.9.1 released 2013-‐‑07-‐‑16 �  0.9.2 Planned 2014-‐‑06-‐‑01 �  1.0.0 Planned 2015-‐‑01-‐‑01

Thrift Roadmap

it is difficult to make predictions, particularly about the future. -‐‑-‐‑ Mark Twain

Open Source Community Developed Apache License Version 2.0


� Web �  thrift.apache.org �  github.com/apache/thrift

� Mail � Users: user-‐‑[email protected] � Developers: dev-‐‑[email protected]

� Chat �  #thrift

� Book � Abernethy (2014), The Programmer’s Guide to Apache Thrift, Manning Publications Co. [hHp://www.manning.com/abernethy/]

Thrift Resources

Chapter 1 is free

* Slide source: Randy Abernethy.

Knowledge and Expertise

Computational Resources Scientific Instruments Algorithms and

Models Archived Data and

Metadata

Advanced Science Tools

Enabling & Democratizing Scientific Research Science Gateways:

Few Noted Examples:

Airavata API

Security

Launch & Manage Jobs

Save/Load configurations and provenance data

Notify progress of job or workflow execution

Real-‐‑Time Monitoring

Execute & Manage Computations

Data Ingest & Discovery Data Movement Data & Provenance Subsystem

Job & Workflow Subsystem

Messaging Subsystem

i Information Subsystem

CIPRES

Neuro Science

Ultrascan

BioVLAB

GAAMP

Param Chem

Academic & Commercial

Clouds

Inter-‐‑ national Grids

Apache Airavata

Apache Airavata

Translating Science Gateway Language...

Interactivity through layers

Mathema'cal* Domain* Resource* Model**Refinement*

Uncertain)es+

Orchestra)on+level+Interac)ons+

Workflow**Steering*

Parametric*Sweeps*

Provenance*

Job+Level+Interac)ons+

Job*launch,*gliding*

Checkpoint/**Restart*

Asynchronous++refinements+

Applica)on+Steering+

Challenges the API

Airavata API in a nutshell � Airavata provides a API to science gateway developers �  Science gateways => diverse requirements � Airavata API needs to be

�  Easy to understand and simple �  Generic enough to support different gateways �  Existing science gateway integration should be smooth �  Flexible for changes arising with different requirements of science gateways

Earlier Airavata Architecture

(a simplified view - evolved over 10 years)

Road to Airavata 1.0 �  First Approach -‐‑ SOAP / WS

�  Pros �  ability to separate out context and the payload �  Already proven tools and techniques (XML, WSDL, WS-‐‑Security etc) �  Clients can easily generate stubs using WSDLs

�  Cons �  Heavy weight �  Data schema changes cannot be handled easily �  Could not support broad range of clients

Contd.. Road to Airavata 1.0 �  Second Approach -‐‑ REST

�  Pros �  Flexible for data representation (JSON or XML) �  Light weight �  BeHer performance

�  Cons �  Multiple object layers �  No standard way to describe the service to the client

Key issues with earlier Airavata API � Only java clients were developed

�  users had to write their own client for other languages � API design was a hybrid model

�  Makes it more complicated internally � Complex data objects are overwhelming to work in REST

�  Lot of marshalling / unmarshalling of data objects � Unnecessary need for a servlet container � Overwhelming number of methods with lots of overloaded methods

Contd..Road to Airavata 1.0 � Third Approach -‐‑ RPC style tools (Apache Thrift, Protocol Buffers, Apache Avro)

�  Ability to communicate easily across different programming languages �  Easy way to generate server and client code

Why Apache Thrift � Apache project �  For Airavata users, a client library that can consume the API is more important than an open API like REST

� Light framework �  No multiple dependencies and servlet containers.

� Easy learning curve to get started �  If carefully crafted, the IDLs and framework support backward and forward compatibility

Clean way to define IDLs with richer data structures

Apache Thrift Integration with Airavata

●  Airavata API server and Orchestrator are thrift services at the moment

●  Other components will also become thrift services in the future

Apache Thrift Integration with Airavata

Experience: What we gain � Able to support clients wriHen in different languages � Clean design � Having different versions of servers

�  TSimpleServer -‐‑ Simple single threaded server �  TThreadPoolServer -‐‑ Uses Java'ʹs built in ThreadPool management �  TNonblockingServer -‐‑ non-‐‑blocking TServer implementation �  THsHaServer -‐‑ extension of the TNonblockingServer to a Half-‐‑Sync/Half-‐‑Async server

Experience Contd.. What we gain

� No need of marshalling / unmarshalling -‐‑ data models used internally �  Server is very robust -‐‑ able to handle large number of concurrent requests.

� Easy to do modifications to the models, since code is auto-‐‑generated � Convenient way to achieve backward compatibility

Lessons Learned � Modularize the data models in order to ease the maintenance

� No maven plugin at the moment, hence you have to commit auto-‐‑generated code.

Lessons Learned Contd..

Lessons Learned Contd..

� Thrift has limited support to handle null values. �  Experiment model is a complex model with lot of other structs. �  Enums cannot be passed as null over the wire even they are specified as optional in the struct

� Thrift has limited documentation and samples �  airavata can be used as a reference

�  hHps://github.com/apache/airavata

Future Directions

� March towards Airavata 1.0 with a stable API � Exploring next generation information model and Messaging Systems

�  Ka{a, flume, fluend, Scribe, Hedwig…. � Refactor Registry Implementation � Airavata architecture to support multi-‐‑tenanted PAAS

�  Motivated by a downstream open source project SciGaP – Science Gateways Platform as a Service

How you can participate/follow

�  Join the party -‐‑ Architecture mailing list � BYOX � X = opinions, software, ideas, code, yourself ..

Take Home �  2 e books on thrift �  awareness of thrift and airavata �  lessons learned � how to get involved � We are under same umbrella for a reason, lets party together

�  Join our Architecture List and help �  Other means??

Discussion, Q & A