1. Aniruddha Gokhale and Jeff Gray Institute for Software Integrated Systems (ISIS) Vanderbilt University Software Composition and Modeling Laboratory University of Alabama at Birmingham Supported by the DARPA PCES program DARPA/AFRL Contract # F33615-03-C-4112 An Integrated Aspect-oriented Model-driven Development Toolsuite for Distributed Real-time and Embedded Systems AOSD Aspect-Oriented Modeling Workshop Chicago, IL March 14, 2005

2. 2 Challenge 1: Tangled Deployment and Configuration Concerns Key challenges in the problem space Network-centric, dynamic, very large-scale “systems of systems” Stringent simultaneous quality of service (QoS) demands Highly diverse & complex problem domains Key challenges in the solution space Enormous accidental & inherent complexities in deployment & configuration Continuous evolution & change Highly heterogeneous platform, language, & tool environments Deployment & configuration concerns of QoS-sensitive distributed systems today are often tangled across (1) several layers of middleware, OS, & networks, and (2) different software lifecycle stages, thereby adversely affecting development & maintenance costs Tangled Deployment Concerns Tangled Configuration Concerns Avionics DoD Scenario Focus: Middleware Configuration and DRE Systems Component Deployment

3. 3 Solution 1: Separation of Concerns via Model Driven Development  Specification & Implementation – Specifying application functionality & QoS, partitioning, & implementation as standalone components  Packaging – Bundling a suite of software binary modules & metadata representing application components  Installation – Populating a repository with packages required by application  Configuration – Configuring the packages with the appropriate parameters to satisfy the functional & systemic requirements of application without constraining to any physical resources  Planning – Making appropriate deployment decisions including identifying the entities, such as CPUs, of the target environment where the packages will be deployed  Preparation – Moving the binaries to the identified entities of the target environment  Launching – Triggering the installed binaries & bringing the application to a ready state  Adaptation – Run-time reconfiguration & resource management to maintain end-to-end QoS Separation of Configuration Concerns Separation of Deployment Concerns Need for automated separation of concerns

4. 4 CoSMIC: Generative Model Driven Development Toolsuite Visual Modeling Collection of domain-specific modeling languages (DSMLs) to address D&C concerns Based on OMG D&C spec Correct-by- construction Strong typing & constraint- checking Addressing crosscutting D&C concerns CoSMIC DSMLs enable untangling D&C concerns Alleviates Accidental Complexities Generative tools to address low- level platform-specific details Enhances OMG MDA Vision MDD enhances OMG Model Driven Architecture (MDA) approach via DSMLs to support QoS- sensitive distributed systems www.dre.vanderbilt.edu/cosmic Metamodeling Uses Generic Modeling Environment (GME) metamodeling capabilities Level of Abstraction Machine code Assembly C/Fortran Programming Languages & Middleware Platforms C++/Java Platforms Component Saturation!!! ! Domain-independent modeling languages State Charts Interaction Diagrams Activity Diagrams Domain-specific modeling languages ESML PICML Metamodels Model-driven Software Development

5. 5 Multiple Levels of Hierarchy Replicated Structures Context Sensitive Challenge 2 : Crosscutting Constraints in Real-Time/Embedded Models Key Challenge: Crosscutting Models A B cde B cde F B cde Changeability??? Crosscutting Constraints – Base models become constrained to capture a particular design – Concerns that are related to some global property are dispersed across the model Solution: Constraint-Specification Aspect Weaver – Model transformations in an aspect-oriented style to capture crosscutting concerns

6. 6 Challenge 3: Scaling up to Large DRE Systems Context  Rich and complex interactions among modeling elements  Need to scale to large systems  Repetitive modeling tasks Problems  Changing requirements have cascading effect across multiple locations in a model  The time to make such changes becomes infeasible to do manually; error prone nature of manual change can lead to incorrect models  Example: Scaling a model from 3 UAVs to 30 UAVs involves a combinatorial amount of changes that becomes nearly impossible to model by hand; similar for large federations of event channels

7. 7 1.CoSMIC is used to model a federated event service with three sites 2.The ECL strategy specifications in C- SAW are used to scale up any site as well as the corresponding connections in the EQAL model. Three steps are included: Add extra CORBA_Gateways to the existing sites Repeatedly replicate the site as an instance Create connections between all of the sites 3.C-SAW takes the original EQAL model and the ECL specifications, and then generates the new scaled-up EQAL model with additional sites: Model weaving to explore design alternatives more rapidly Design decisions crosscut model hierarchy Removes manual error resulting from tedious/repetitious changes Solution 3: Aspect Model Weaving via CoSMIC+C-SAW 12 3 ECL Specifications aspect Start( ) { scaleUpSites(1, 8, 4); } strategy scaleUpSites(site_id, max, idx: integer) { iterateSite_r(idx-1, 1, max, idx); addSite_r(site_id, max, idx); addCon_r1(site_id, max, 1, 1, idx); } strategy iterateSite_r(oldmax, oldidx, max, idx : integer) { declare id_str :string; if (oldidx <=oldmax) then id_str := intToString(oldidx); rootFolder().findModel("NewGateway_Federation"). findModel("Site " + id_str).addGateWay_r(max, idx); iterateSite_r(oldmax, oldidx+1, max, idx); endif; } aspect Start( ) { scaleUpSites(1, 8, 4); } strategy scaleUpSites(site_id, max, idx: integer) { iterateSite_r(idx-1, 1, max, idx); addSite_r(site_id, max, idx); addCon_r1(site_id, max, 1, 1, idx); } strategy iterateSite_r(oldmax, oldidx, max, idx : integer) { declare id_str :string; if (oldidx <=oldmax) then id_str := intToString(oldidx); rootFolder().findModel("NewGateway_Federation"). findModel("Site " + id_str).addGateWay_r(max, idx); iterateSite_r(oldmax, oldidx+1, max, idx); endif; } EQAL/CoSMIC Model with 3 sites EQAL Model with 8 sites Weaver ECL strategies shown in paper…

8. 8 Project Web Pages http://www.dre.vanderbilt.edu/cosmic http://www.gray-area.org/Research/C-SAW/ Contains papers, downloads, video demos C-SAW Aspect Model Weaver CoSMIC Modeling Languages and Tools

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10. 10 New Demands on Distributed Real-time & Embedded (DRE) Systems Standalone real-time & embedded systems Stringent quality of service (QoS) demands e.g., latency, jitter, footprint Resource constrained Standalone real-time & embedded systems Stringent quality of service (QoS) demands e.g., latency, jitter, footprint Resource constrained The Past Military/Civilian distributed real-time & embedded (DRE) systems Network-centric & larger-scale “systems of systems” Stringent simultaneous QoS demands e.g., dependability, security, scalability, thruput Dynamic context Military/Civilian distributed real-time & embedded (DRE) systems Network-centric & larger-scale “systems of systems” Stringent simultaneous QoS demands e.g., dependability, security, scalability, thruput Dynamic context The Future

11. 11 PICML: Capturing & Modeling D&C Crosscutting Concerns Context Configuring & Deploying component- based applications using XML meta-data Problem Meta-data split across multiple XML descriptors Inter-dependencies between descriptors XML is error-prone to read/write manually No guarantees about semantic validity (only syntactic validation possible) If meta-data is wrong, what about my application? Solution PICML = Platform Independent Component Modeling Language Modeling paradigm developed using Generic Modeling Environment (GME) Capture dependencies visually Define semantic constraints using Object Constraint Language (OCL) Generate domain specific meta-data from models Correct-by-construction

12. 12 EQAL: Capturing Event QoS Aspects in PICML Context Publisher/subscriber services are highly configurable XML-based specification of QoS properties Problems Multiple dissimilar services Semantically invalid operating policies Error-prone handwritten XML Solution Use models to enforce policy constraints & synthesize configuration files EQAL = Event QoS Aspect Language EQAL is part of PICML within the CoSMIC suite Built in the Generic Modeling Environment (GME) Addresses publisher/subscriber service configuration and deployment challenges Models specify service configurations and deployments Aspects decouple D&C concerns Constraints ensure semantic validity Interpreters generate descriptor files