3/4/98 pwg presentation - events and notification1 events and notification scott isaacson

3/4/98 PWG Presentation - Events and Notification

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Events and Notification

Scott Isaacson


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Agenda

OMG Event Channel Notification Channel

The Open Group (TOG)Java ImplementationsNDPS


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OMG Basics

Event Channel

TypedEvent Channel

Notification Channel

- untyped events- push/pull- connect/disconnect

- typed events

TypedNotification

Channel

Networked Channel

- structured events- event objects- filtering- time stamping- delivery QoS priority time-out retry persistent- durable conns.

- transactions- security- named connections- routing- admin topology batching stats

- typed events


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OMG Interfaces

QoS UNSUPPORTED_PROPERTY UNAVAILABLE_PROPERTY UNSUPPORTED_VALUE UNAVAILABLE_VALUE BAD_PROPERTY BAD_TYPE BAD_VALUE


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OMG Interfaces

FilterMappingFilterFilterFactoryFilters: 4/15 pages of IDLFilter Objects work on

Any, Structured, TypedChannel -> Admin -> Proxy ->

Message


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OMG Events

Event Transmission Any, Structured, Sequences of

StructuredClient chooses, Channel maps

Any -> Structured Structured -> Any etc.


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Structured Events

Event Header Fixed (domain, type, name) Variable (set of properties)

priority, start-time, stop-time, time-out

Event Body Filterable Event Fields (set of

properties) Remaining Body (OctetStream)


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OMG Other

System Events Events on the Event Channel

Constraint Grammar NOT: vh[3].name == ‘priority’ AND

vh[3].value >2 YES: vh[‘priority’] > 2

Run time variables $curtime; $priority IS vh[‘priority’]


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OMG Other cont.

QoS set at all levels: Per Channel Per Admin Per Proxy Per Message

subscription_changeoffer_changeType Repository: event -> properties


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TOG

timely warning of impending problems notifying system administrators of failing

processes and system components speedily identifying root causes of problems in

ever more complex systems automatically fixing problems before service

levels are degraded support application-specific events for cross-

application correlation and communication 246 pages


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TOG: Event Report

event identification, category and subcategorydate/time/timezone of originoriginating process (physical ID)component, subcomponent, module,

subroutine, source code line, and so on, identifiers

priority and severity code text messageend-user device identifier.


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TOG: Notification Methods

email message notificationbeeper calledlog file entry postedrow inserted into some table in some

databasemanaged server stored-procedure

execution


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TOG: Methods cont.

SNMP alert raisedasynchronous desktop visual alert (for

example, GUI pop-up)visual cue in iconic representations

(for example, color change)arbitrary program executioninvoke management services at API

level


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TOG:Components

ChannelSupplier, Supplier ProxyConsumer, Consumer ProxyRepository

Filer, Schema, Event, Registered ClientsGateways to other event systems


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TOG: Tasks

configurationauthorizationregistrationconnectiondeliverymaintenance.


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TOG: Interfaces

the Registration interfacethe Event Type interfacethe Supplier Interfacethe Filter Interfacethe Consumer Interfacethe Management Interface.


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TOG: Gateways

Support OMGSupport SNMPSupport CMIPSupport XMPSupport DCE


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TOG: C Data Structures

EVENT HEADER

typedef struct ems_hdr_s_t { ems_eventid_t eventid; ems_origin_t origin; ems_severity_t severity; ems_utc_t received; ems_utc_t delivered; ems_priority_t priority;} ems_hdr_t;

EVENT BODY

typedef struct ems_event_s_t { ems_hdr_t header; ems_ulong_int count; ems_attribute_t item[1];} ems_event_t;


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TOG: Filters

#define ems_c_attr_op_eq (0)#define ems_c_attr_op_gt (1)#define ems_c_attr_op_lt (2)#define ems_c_attr_op_ge (3)#define ems_c_attr_op_le (4)#define ems_c_attr_op_ne (5)#define ems_c_attr_op_bitand (6)#define ems_c_attr_op_substr (7)


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JAVA

JavaSoft: Java Message Service Events Messages not Email Messages

Java Message Service Technology: Leveraging Messaging Systems for Enterprise Applications

Speaker: Mark Hapner, Senior Staff Engineer, Sun Microsystems, Inc.


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http://java.sun.com/javaone/ javaone98/tracks.html

Abstract: Enterprise infrastructures rely increasingly on messsage-oriented middleware. The Java Message Service (JMS) technology is the Java Enterprise API technology for messaging. JMS provides capabilities for reliable queues and publish/subscribe messaging. Reliable queues provide the basis for asynchronous task management within an enterprise. Publish/subscribe functionality supports dynamic interconnection of information sources with subscribers interested in that information. This talk describe the JMS API technology and its uses in

modern enterprises.


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Java: Open Horizon

Ambrosia Clients

Publisher/Subcriber (push)Solicit/Response (query)Request/Reply (pull)

BrokerIntermediary

100% Java


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Ambrosia Classes and Interfaces

Connection Credentials Evenlope Message MessageHandler Publication Session Subject Subscription


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Connection

authenticate (Credentials)connect(Broker)disconnet(boolean forceUnSubscribe)addMessageHandler(MH)removeMessageHandler(MH)getSubjetTree()getSubscriptions()


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Credentials

Constructor String userId String password

clear()getUid()set()acquire() - privateKey


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Envelope

getMessage()getID()getLabel()


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Message

byte[] getBody()setBody(byte[])getPublishers()getSubject()String toString()


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MessageHandler

Bind()unbind()getBindings()replaceHandler()


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Publication

Cancel()getEnvelope()join()start()suspend()


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Session

getConnection()isGuaranteedAllowed()isPublishAllowed()isSubscribeAllowed()publish(), subscribe()request(), reply() (solicit(MH))Transaction Support


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Subject

getParent()getChildren()getName()“stocks.*”“stocks.ACME”“printer.tray1.empty”


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Subscription

cancel()getDeliveryLabel()join()start()suspend()


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NDPS Event Notification Service (ENS) Goals

Provide extensible, asynchronous distribution channel for event data. Supportive of diverse address schemes

and delivery methods Transport and platform neutral Localization friendly Secure Efficient in its use of network bandwidth


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ENS Principles

Notification Protocol is a separable, general purpose protocol, it IS NOT just a subset of the Print protocol

Use a “channel” for scalabilityThe service makes it possible for the

client (not server) to localize/translateUse “mixed” (human and machine)

consumption models


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No Channel

Client

Client

Client

Client

Client

Printer

Printer

Printer

Printer

Printer


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Single Channel

Client

Client

Client

Client

Client

Printer

Printer

Printer

Printer

Printer


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Communities of Interest: Multiple Channels

Client

Client

Client

Client

Client

Printer

Printer

Printer

Printer

Printer


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Very Large Numbers of Clients

Printer

Clients


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ENS Architecture

Registration

Request

/

Report

222-4096222-4096

Bill

Notification

Persistent

Requests

NDS Tree

Notification Supplier

Notification Consumer

ENS


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ENS Scenario

1

2a 2b

3

4

5

6a

6b

6c

6d

6e

1. Printer Agent registers with Broker

2a. Print Job with Profile or 2b. Add Profile with Profile

3. Printer Agent remembers “some interest”

4. An event happens

5. Report the event

6. a) programmatic; b) log; c) email; d) pop-up; e) directed pop-up

ENS

profile


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Finding a Broker

Admin configuration Named directory (NDS) object

SLP IP

SAP IPX


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Submitting a Profile

Printer Agent only reports an event if there is some interest

Profile with Job (Security: User role) Job and Printer events (printer only

while Job is active)Profile outside of Job (Security:

Operator role) Printer and All Jobs


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What is a Profile?

Notification Profile persistence consumer name language id method oid delivery address set of event objects


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I18N

Client requests a “language”Report Contains

Identifiers Strings

In client preference if possibleIn server default config otherwise

Remote Identifier to String database Cached on client Support for any language


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Types of Events

Abstract Events Printer

Error, Warning, Report

JobError, Warning, Report

Other

State Change Any MIB Object - value change Instrumented for MIB Alerts


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UI and Profiles

UI for: All Printer events All Printer Error events Specific Printer Error events

“When the media in tray 1 goes to 0”Objects and Attributes


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Event Report

Event Report event type containing class oid and id filter class oid object class oid and id event oid event attribute set time


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NDPS: Publish/Subscribe with variations

Many (extensible) notification methodsSubscribe by proxy through the printer

Instead of finding Printer Agent AND Channel Just find Printer Agent Subscription is made

Listener (programmatic)GuaranteedHalt the Service

3/4/98 pwg presentation - events and notification1 events and notification scott isaacson

Documents

pwg presentation events

notification1 events

value slide

t origin ems

t header ems

t severity ems

t eventid ems

vhpriority slide