Angelo Corsaro, Ph.D. Chief Technology Officer! OMG DDS Sig Co-Chair PrismTech

Transcription

1 Angelo Corsaro, Ph.D. Chief Technology Officer! OMG DDS Sig Co-Chair PrismTech

2 Standards Scopes

3 Standards Compared DDS Standard v Programming Language Independent API for Data- Centric Pub/Sub Interoperable Wire- Protocol (DDSI/RTPS) JMS Standard v Java Messaging API (Pub/ Sub + PTP) portable across messaging implementations

4 Standards Compared DDS ensures portability and interoperability across implementation of the standard Application DDS API DDSI Standard JMS focuses only on application portability across implementation of the standard Application JMS API JMS Provider Standard

5 Standards Compared DDS Standard Promotes Fully Distributed Architectures Provides mechanisms for transparently using Brokers/ Routers JMS Standard Promotes Hub and Spoke Architectures Fully distributed architectures are possible but complicated by some use cases

6 Standardization " Activity

7 JMS The JMS standard has not been evolving after the v1.1 released in 2002

8 DDS Standard Evolution App DDS 2004 Standard API Standard API for Data- Centric Real-Time Pub/Sub Automatic fail-over Persistence Dynamic Discovery Content Filtering / Queries

9 DDS Standard Evolution App DDS DDSI/RTPS Standard API network App DDS DDSI/RTPS Interoperable Wire Protocol High Performance Interoperable Wire Protocol

10 DDS Standard Evolution App DDS 2008 UML4DDS DDSI/RTPS UML-Based Modeling DDS applications Standard API network of 2008 UML4DDS App DDS DDSI/RTPS Interoperable Wire Protocol

11 DDS Standard Evolution 2010 X-Types App DDS 2008 UML4DDS DDSI/RTPS Standard API network App DDS 2008 UML4DDS DDSI/RTPS 2010 X-Types Extensible/Evolvable Type System Dynamic Topic Types, Data Readers & Writers Encoding Negotiation Interoperable Wire Protocol

12 DDS Standard Evolution 2010 X-Types App DDS 2008 UML4DDS DDSI/RTPS ISO C++ DDS PSM Simple, Safe, Efficient, Elegant and Ergonomic API 2010 ISO-C++ PSM Standard API network App DDS 2008 UML4DDS DDSI/RTPS 2010 X-Types Interoperable Wire Protocol

13 DDS Standard Evolution 2010 X-Types App DDS 2008 UML4DDS DDSI/RTPS Java 5 DDS PSM Simple, Safe, Efficient, Elegant and Ergonomic API 2010 ISO-C++ PSM Standard API network 2010 Java5 PSM App DDS 2008 UML4DDS DDSI/RTPS 2010 X-Types Interoperable Wire Protocol

14 DDS Standard Evolution 2010 X-Types App DDS 2008 UML4DDS DDSI/RTPS 2011 Web-DDS 2010 ISO-C++ PSM Standard API network 2010 Java5 PSM 2011 Web-DDS App DDS 2008 UML4DDS DDSI/RTPS 2010 X-Types Interoperable Wire Protocol Standardized way of accessing DDS from Web Technologies REST, W3C WS-*, RSS, etc.

15 DDS Standard Evolution 2010 X-Types App DDS ULS-DDSI 2008 UML4DDS Web-DDS 2010 ISO-C++ PSM Standard API network 2010 Java5 PSM 2011 Web-DDS UML4DDS App DDS ULS-DDSI X-Types Ultra-Large Scale Extensions to the DDSI/RTPS wireprotocol New Discovery Support for TCP, etc. Interoperable Wire Protocol

16 DDS Standard Evolution 2010 X-Types App DDS ULS-DDSI 2008 UML4DDS Web-DDS 2012 Security 2010 ISO-C++ PSM Standard API network 2010 Java5 PSM 2012 Security 2011 Web-DDS UML4DDS App DDS ULS-DDSI X-Types Interoperable Wire Protocol Interoperable Security Architecture Pluggable Policy / Labeling and Tagging

17 DDS Standard Evolution 2010 X-Types 2012 DDS-RMI App DDS ULS-DDSI 2008 UML4DDS Web-DDS 2012 Security Remote Method Invocations over DDS Synchronous, Asynchronous and one ways RMI 2010 ISO-C++ PSM Standard API network 2010 Java5 PSM 2012 Security 2011 Web-DDS UML4DDS App DDS ULS-DDSI DDS-RMI X-Types Interoperable Wire Protocol

18 Mapping JMS to DDS

19 JMS DDS Connection Session Pub/Sub Establishes connection with the Broker Connection Session Producer Destination Consumer Publisher Gives access to a DDS Domain DataWriter Domain Participant Topic Subscriber DataReader

20 JMS DDS Connection Session Pub/Sub Connection Session Producer Destination Consumer Establishes a JMS Session Publisher DataWriter Domain Participant Manage Topic publishers and subscribers sessions Subscriber DataReader

21 JMS DDS Connection Session Pub/Sub Connection Session Producer Destination Consumer Publisher DataWriter Domain Participant Topic Subscriber DataReader Messaging Abstractions. A Destination can be a Topic or a Queue Reader/Writer for application defined Topic Types

22 Note: Topics are the kind of JMS Destination associated with the Pub/Sub Domain Pub/Sub & Topics

23 JMS Topics A Topic defines the subject of publications and subscriptions The topic name has a weakly defined semantics w.r.t. the subscription matching Topics are Administered Objects and should preferably be defined outside the application. API for local definition also exist

24 DDS Topics [1/2] com.myco.vpos A Topic defines the subject of publications and subscriptions A Topic has associated a user defined extensible type and QoS The Topic name, type and QoS have a well defined role in matching subscriptions Topics can be discovered or locally defined struct VehiclePosition{! string long x;! longy;! }! DURABILITY, DEADLINE, PRIORITY,

25 DDS Topics [2/2] com.myco.vpos DDS Topic types can have associated keys Each unique key-value identify a Topic Instance a specific stream of values struct VehiclePosition{! string long x;! longy;! }! DURABILITY, DEADLINE, PRIORITY,

26 Plugging into JMS/DDS

27 JMS Connection Session Pub/Sub Connection Session Establishes connection with the Broker Producer Topic Consumer // Get connectionfactory from JNDI! Connection c =! connectionfactory.createconnection();! Publisher Domain Participant Topic Subscriber Reader/Writers User Defined for Types DataWrter DataReader

28 JMS Connection Session Pub/Sub Connection Session Producer Topic Consumer Establishes a JMS Session // Get connectionfactory from JNDI! Connection c =! connectionfactory.createconnection();! Session s =! c.createsession(false,! Session.AUTO_ACKNOWLDEGE);! Reader/Writers User Defined for Types

29 JMS Connection Session Pub/Sub Connection Session Producer Destination Consumer Reader/Writers Messaging Abstractions. User Defined A Destination for Types can be a Topic or a Queue // Get connectionfactory from JNDI! Connection c =! connectionfactory.createconnection();! Session s =! c.createsession(false,! Session.AUTO_ACKNOWLDEGE);! // Look-up destination from JNDI! Destination d =! (Destination )jndi.lookup(destname);!! // Create a Producer! MessageProducer mp = s.createproducer(d);!! // Create a Consumer! MessageConsumer mc = s.createconsumer(d);!

30 DDS Connection Session Pub/Sub DomainParticipant dp =! thedomainparticipantfactory().create_participant(0);! Publisher Gives access to a DDS Domain DataWriter Domain Participant Topic Subscriber DataReader

31 DDS Connection Session Pub/Sub DomainParticipant dp =! thedomainparticipantfactory().create_participant(0);! // Create a Publisher / Subscriber! Publisher p = dp.create_publisher();! Subscriber s = dp.create_subscriber();! // Create a Topic! Topic<Foo> t = dp.create_topic<foo>(name)! Publisher DataWriter Domain Participant Manage Topic publishers and subscribers sessions Subscriber DataReader

32 DDS Connection Session Pub/Sub DomainParticipant dp =! thedomainparticipantfactory().create_participant(0);! // Create a Publisher / Subscriber! Publisher p = dp.create_publisher();! Subscriber s = dp.create_subscriber();! // Create a Topic! Topic<Foo> t = dp.create_topic<foo>(name)! // Create a DataWriter/DataWriter! DataWriter<Foo> dw = pub.create_datawriter(t);! DataReader<Foo> dr = sub.create_datareader(t);! Publisher DataWriter Domain Participant Topic Subscriber DataReader Reader/Writer for application defined Topic Types

33 JMS allows to distribute Messages DDS allows to share Data Both DDS and JMS provide a Topic-Based Pub/Sub abstraction to match interests Messages & Data

34 JMS Message Text JMS Messages are composed by Header Used for routing Property Filtering, etc. Body Data 5 Different Body types are supported Stream Map Header Body Body Message Object Properties Byte

35 Topic Types Topic types can be defined in IDL, UML, XML, Java Topics types are extensible and evolvable Rich set of annotations to deal with fields that might be optional, shared, etc. Each unique key value identifies a Topic Instance Topic Instance, can be Created, Read, Updated, and Disposed (CRUD) Topic Topic Type Topic Key Topic Instances struct VehiclePosition{! string plate; //@Key! long x;! long y;! }! TrakCo.VehiclePosition VehiclePosition plate A123 B456 C789 x y

36 In Summary DDS Topics have associated user defined Types These user defined types are used to read/write topic instances JMS Topics represent a kind of Destination for Messages User-Types have to be mapped into one of the 5 message bodies defined by JMS

37 Sending/Receiving Messages

38 Sending Message JMS provides 5 message body types Messages are sent through the Producer // Create a Text Message! TextMessage tm = s.createtextmessage( Hello );! // Send the Text Message! mp.send(tm);!!

39 Sending Message JMS provides 5 message body types Messages are sent through the Producer class VehiclePosition! implements java.io.serializable {! private String plate;! private long x;! private long y;!! // Ctors / Setters / Getters! }!! VehiclePosition vp =! new VehiclePosition( Hello, 10, 20);!! // Create an Object Message! ObjectMessage om = s.createobjectmessage(vp);! // Send the Object Message! mp.send(om);!!

40 Receiving Messages JMS Application receive generic Message and have to understand what the type is (usually via down-casts) Messages can be read proactively or listener can be registered // Receive Message! TextMessage tm = (TextMessage)ms.receive();! String str = tm.gettext();!! Messages are retrieved one at the time

41 Receiving Messages JMS Application receive generic Message and have to understand what the type is (usually via down-casts) Messages can be read proactively or listener can be registered! ObjectMessage om = (ObjectMessage)ms.receive();! VehiclePosition vp = (VehiclePosition)om.getObject();!! // Notice that any of the casts above could fail! // at runtime! Messages are retrieved one at the time

42 Reading/Writing " Data

43 Writing Data DDS allows applications to define their own data types and associate them with Topics Topic updates are written through the DataWriter class VehiclePosition {! public:! const std::string& plate() const;! void plate(const std::string& s);! int32_t x() const;! void x(int32_t i);! int32_t y() const;! void y(int32_t i);! // Encapsulated State Representation! };! VehiclePosition vp( Hello, 10, 20);! dw << vp;!! // Alternative Syntax! dw.write(vp);!!!

44 Reading Data DDS provide a strongly typed API for reading data that relies on DataReaders Messages can be read proactively or listener can be registered DDS provides A very flexible selection mechanism for topic samples // Read Data!! std::vector<vehicleposition> data(size);! std::vector<sampleinfo> info(size);!! dr.read(data.begin(), info.begin(), size);!

45 DDS vs. JMS DDS provides an end-toend type-safe abstraction for distributing publications of user defined topic types // Read Data!! std::vector<vehicleposition> data(size);! std::vector<sampleinfo> info(size);!! dr.read(data.begin(), info.begin(), size);! JMS requires user to guess types this introduce potential for runtime errors // Receive Message! TextMessage tm = (TextMessage)ms.receive();! String str = tm.gettext();!! // =============================================!! ObjectMessage om = (ObjectMessage)ms.receive();! VehiclePosition vp = (VehiclePosition)om.getObject();!! // Notice that any of the casts above could fail! // at runtime!

46 DDS. What Else?

47 Instance/History Management An Instance per unique key value An update for a Topic Instance is called Sample DDS can maintain a configurable history of samples per Topic Instance

48 Topic Instances vs. Messages DDS com.myco.vpos JMS com.myco.vpos

49 Topic Instances vs. Messages com.myco.vpos DDS A JMS New com.myco.vpos A

50 Topic Instances vs. Messages com.myco.vpos DDS A B JMS New New B com.myco.vpos A

51 Topic Instances vs. Messages A com.myco.vpos DDS A B JMS New New A B com.myco.vpos A

52 Topic Instances vs. Messages DDS A A com.myco.vpos A B JMS New New A A B A com.myco.vpos

53 Topic Instances vs. Messages DDS A A B com.myco.vpos A B JMS New New B A A B A com.myco.vpos

54 Topic Instances vs. Messages DDS A B Disposed A B com.myco.vpos A B JMS New New B A A B A com.myco.vpos

55 Dynamic Discovery DDS dynamically discovers publishers, subscribers as well as Topics Dynamic Discovery has a key role in subscriptions matching No global configuration is required

56 QoS Framework DDS provides a mechanism for end-to-end QoS matching Communication is established iff the QoS offered by the publisher matches/exceeds that requested by the subscriber QoS QoS Publisher DomainParticipant... QoS DataWriter DataWriter QoS Type Matching QoS Topic writes Type... writes Type Topic QoS Name reads reads Name QoS matching QoS DataReader DataReader QoS... QoS QoS Subscriber DomainParticipant

57 QoS Policies QoS Policy Applicability RxO Modifiable DURABILITY T, DR, DW Y N DURABILITY SERVICE LIFESPAN HISTORY PRESENTATION RELIABILITY PARTITION DESTINATION ORDER OWNERSHIP OWNERSHIP STRENGTH DEADLINE LATENCY BUDGET TRANSPORT PRIORITY T, DW N N T, DW N/A Y T, DR, DW N N P, S Y N T, DR, DW Y N P, S N Y T, DR, DW Y N T, DR, DW Y N DW N/A Y T, DR, DW Y Y T, DR, DW Y Y T, DW N/A Y Data Availability Data Delivery Data Timeliness QoS Policy Applicability RxO Modifiable TIME BASED FILTER RESOURCE LIMITS ENTITY FACTORY USER DATA TOPIC DATA GROUP DATA LIVELINESS WRITER DATA LIFECYCLE READER DATA LIFECYCLE DR N/A Y T, DR, DW N N DP, DR, DW N Y T N Y P, S N Y T, DR, DW Y N DW N/A Y DR N/A Y Resources Configuration Lifecycle

58 Content Awareness DDS make it possible express filters and queries on the whole content of a topic type Filters can be used to establish content filtered subscriptions Queries can be used to create local views of available data struct VehiclePosition{! string long x;! long y;! }! Filter Examples: x < %0 AND y < %1 y BETWEEN (10 AND 20)

59 High Performance OpenSplice DDS is 2.5x-3x faster than high performance JMS implementations

60 High Performance OpenSplice DDS delivers very low and predictable latencies No other Pub/Sub technology can approach similar level of performance! Latency (usec) Size (bytes)

61 JMS Legacy?

62 Integrating JMS with DDS Existing JMS systems can be easily integrated with DDS today using Apache Camel High Performance, High Availability Integration of DDS with JMS will also available through the Blend- Box (available later this year) ULS DDSI OpenSplice DDS Connector DDSI DDS Connectors OpenSplice DDS BLEND-Box REST Custom Connectors Custom JMS WS-* Web Connectors compliant with the Web-Enabled DDS Specificaiton

63 DDS in Action

64 Summing Up

65 Concluding Remarks DDS is a powerful lively standard for publish/ subscribe DDS provides some very useful abstractions not available in JMS, such as user-defined types, instances, history, etc. DDS can be as simple to use as JMS, but when required provides far more knobs for tuning scalability, performance and QoS

66 OpenSplice DDS Delivering Performance, Openness, and Freedom