Difference between revisions of "Common Libraries Specification"

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The core facilities of the e-Infrastructure include a set of Java libraries that compose into solutions for managing the software and hardware of the e-Infrastructure, as well as for interacting with those resources. This document overviews such ''common libraries''.
  
 
== Overview ==
 
== Overview ==
  
−
A brief overview of the subsystem should be here. It should include the key features.  
+
Common libraries are grouped in three main distributions:
 +
 
 +
* the [[Featherweight_Stack|Featherweight Stack]] (FWS) is the client stack of the e-Infrastructure, i.e. the set of libraries that allow clients to interact with its services, first and foremost the services of its enabling technologies;
 +
 
 +
* [[SmartGears|Smartgears]] is a set of libraries that transform services and service containers into resources of the e-Infrastructure. SmartGears meets, among others, the description, publication, lifecycle management, and controlled sharing requirements which characterise hardware and software managed by the e-Infrastructure;
 +
 
 +
* the [https://gcore.wiki.gcube-system.org/gCube gCube Application Framework] (gCF) is a comprehensive framework to develop services for the e-Infrastructure, i.e. software written to run and be managed in it.
  
 
=== Key features ===
 
=== Key features ===
  
−
;Lightweight integration mechanisms with existing technologies
+
Collectively, the common libraries support the following management functions:
−
:...
+
  
−
;Extensible Software Model
+
; '''publication and discovery'''
−
:...
+
: periodic and event-based publication of ''resource profiles'' from initial configurations, both for hardware and software;
 +
: high-level models of resources, resource queries and query results;
 +
: best-effort discovery strategies with caching and fault tolerance;
 +
: resource encryption and decryption for publication and querying;
  
−
;Different level of engagements
+
; '''lifecycle management'''
−
:...
+
: state tracking, event-based state transitions, and remotely controlled state transitions, both for hardware and software; 
  
−
;Encryption/decryption of resources
+
; '''controlled sharing'''
−
:...
+
:resource allocation to distinguished groups of users in alignment with dynamic policies, both for hardware and software resources;
 +
:policy enforcement at deployment time (for hardware) and at call time (for software);
 +
:policy propagation in outgoing calls;
 +
 
 +
; '''security management'''
 +
:authentication and authorisation of calls to software resources.  
 +
 
 +
; '''development support for stateful services'''
 +
: WSRF-compliant support for access, persistence, publication, and discovery of service instances;
 +
 
 +
; '''plugin management'''
 +
:plugin discovery, registration, unregistration for software resources;
  
 
== Design ==
 
== Design ==
  
 
=== Philosophy ===
 
=== Philosophy ===
−
This is the rationale behind the design. An example will be provided.  
+
 
 +
The available common libraries reflect two different design orientations:
 +
 
 +
* gCF is a conventional development framework that trades off development simplicity for development for flexibility. It is a library that sits at centre of software design and at the top of the software stack, providing solutions in the context of a well-defined set of technologies and in the assumption of deployment to a specific service container. The tradeoff is most advantageous for the services of the enabling technology, as it offers maximum integration between software and e-Infrastructure. Indeed, the framework is the basis upon which the vast majority of the service of the e-Infrastructure are built.
 +
 
 +
* SmartGears is instead designed as a "resource enabler" for existing software and service containers, where development and deployment cannot and should not be constrained.  SmartGears delivers its management functions in a standard manner, i.e relying only on Servlet specifications, and transparently, i.e. without demanding source-level dependencies from applications. Overall, SmartGears can bring a wide range of software under the management regime of the e-Infrastructure, without requiring dedicated development. At the same time, it allows new services of the enabling technology to evolve along standard pathways, embracing technologies other than those mandated by gCF.
 +
 
 +
* Like SmartGears, the FWS is independent from technologies used by service implementations. The featherweight nature of the stack is in the footprint of its components, which is very small in terms of code, dependencies, and overall usage requirements. Overall, the FWS simplifies the task of clients that wish to interact with any services managed by the e-Infrastructure, gCF-based or SmartGears-based, thereby encouraging uptake.
 +
 
 +
Overall, the simplifications allowed by gCF have been instrumental to the rapid and consistent growth of the system, reducing significantly administration and development costs for hardware and software resources explicitly allocated to the system or developed for it. The commitment to lightweight integration mechanisms and design modularity in SmartGears and the FWS aligns with modern practices and brings a wider range of resources under the management regime of the e-Infrastructure.
  
 
=== Architecture ===
 
=== Architecture ===
−
* '''common-ghn-client''': a client container that discovers and manages an open-ended set of facilities on client nodes (we call them client services)
 
−
* '''common-ghn-client-proxy''': key client service in the client container. installs an embedded HTTP proxy that intercepts client calls in full transparency from client code
 
−
* '''common-ghn-service''': management facilities to manage HTTP services that run in a servlet container in full transparency from the services themselves
 
−
* '''common-clients''': base framework for client library development, gCore-independent
 
−
* '''common-gcore-clients''': gCore-bridge for common-clients
 
−
* '''common-scope''': scope and service map handling facilities
 
−
* '''common-resource''': reference implementation of the new Resource Model
 
−
* '''common-resource-publisher''': publishing of gCube resources according to the new Resource Model 
 
−
* '''common-resource-access''': discovery of gCube resources according to the new Resource Model
 
−
* '''common-utils-encryption''': encryption/decryption utilities to be exploited in the common-resources
 
  
−
== Deployment ==
+
The main common libraries are the following:
−
Usually, a subsystem consists of a number of number of components. This section describes the setting governing components deployment, e.g. the hardware components where software components are expected to be deployed. In particular, two deployment scenarios should be discussed, i.e. Large deployment and Small deployment if appropriate. If it not appropriate, one deployment diagram has to be produced.
+
  
−
=== Large deployment ===
+
* '''gcf''': the gCube Application Framework, a one-stop solution for resource management support and software resource development support;
  
−
A deployment diagram suggesting the deployment schema that maximizes scalability should be described here.
+
* '''common-smartgears''': transparent management support for Servlet-based containers, applications, and services;
  
−
=== Small deployment ===
+
* '''common-scope''': scope handling facilities for policy management;
  
−
A deployment diagram suggesting the "minimal" deployment schema should be described here.
+
* '''common-validator''': annotation-based object validation facilities;
  
−
== Use Cases ==
+
* '''common-utils-encryption''':  encryption and decryption support;
−
The subsystem has been conceived to support a number of use cases moreover it will be used to serve a number of scenarios. This area will collect these "success stories".
+
  
−
=== Well suited Use Cases ===
+
* '''common-gcore-resources''': object binding of the resource model;
  
−
Describe here scenarios where the subsystem proves to outperform other approaches.
+
* '''common-events''': annotation-based eventing support;
  
−
=== Less well suited Use Cases ===
+
* '''common-gcore-stubs''':client support for  JAXWS-based proxies of remote gCF-based services;
  
−
Describe here scenarios where the subsystem partially satisfied the expectations.
+
* '''common-gcube-calls''': base layer support for outgoing calls to any infrastructural service;
 +
 
 +
* '''common-jaxws-calls''': JAX-WS binding of common-gcube-calls;
 +
 
 +
* '''discovery-client''': generic API to formulate and submit queries for resource descriptions.
 +
 
 +
* '''ic-client''': extends discovery-client to target the Information Collector service;
 +
 
 +
* '''registry-publisher''': support to publish resource description with the Registry service;
 +
 
 +
* '''common-clients''': base layer for high leve client libraries to any infrastructural service;
 +
 
 +
* '''common-featherweight-clients''': extends common-clients for clients of standard gCF-based services;
 +
 
 +
* '''common-gcube-clients''': extends common-clients for clients of SmartGears-enabled services;
 +
 
 +
== Deployment ==
 +
Common Libraries are a set of facilities available as Java libraries. Therefore, there is no deployment scheme for them. They are just individually and independently co-deployed with components that need to use a particular feature that one of the offers.

Latest revision as of 11:33, 8 November 2013

The core facilities of the e-Infrastructure include a set of Java libraries that compose into solutions for managing the software and hardware of the e-Infrastructure, as well as for interacting with those resources. This document overviews such common libraries.

Overview

Common libraries are grouped in three main distributions:

  • the Featherweight Stack (FWS) is the client stack of the e-Infrastructure, i.e. the set of libraries that allow clients to interact with its services, first and foremost the services of its enabling technologies;
  • Smartgears is a set of libraries that transform services and service containers into resources of the e-Infrastructure. SmartGears meets, among others, the description, publication, lifecycle management, and controlled sharing requirements which characterise hardware and software managed by the e-Infrastructure;
  • the gCube Application Framework (gCF) is a comprehensive framework to develop services for the e-Infrastructure, i.e. software written to run and be managed in it.

Key features

Collectively, the common libraries support the following management functions:

publication and discovery
periodic and event-based publication of resource profiles from initial configurations, both for hardware and software;
high-level models of resources, resource queries and query results;
best-effort discovery strategies with caching and fault tolerance;
resource encryption and decryption for publication and querying;
lifecycle management
state tracking, event-based state transitions, and remotely controlled state transitions, both for hardware and software;
controlled sharing
resource allocation to distinguished groups of users in alignment with dynamic policies, both for hardware and software resources;
policy enforcement at deployment time (for hardware) and at call time (for software);
policy propagation in outgoing calls;
security management
authentication and authorisation of calls to software resources.
development support for stateful services
WSRF-compliant support for access, persistence, publication, and discovery of service instances;
plugin management
plugin discovery, registration, unregistration for software resources;

Design

Philosophy

The available common libraries reflect two different design orientations:

  • gCF is a conventional development framework that trades off development simplicity for development for flexibility. It is a library that sits at centre of software design and at the top of the software stack, providing solutions in the context of a well-defined set of technologies and in the assumption of deployment to a specific service container. The tradeoff is most advantageous for the services of the enabling technology, as it offers maximum integration between software and e-Infrastructure. Indeed, the framework is the basis upon which the vast majority of the service of the e-Infrastructure are built.
  • SmartGears is instead designed as a "resource enabler" for existing software and service containers, where development and deployment cannot and should not be constrained. SmartGears delivers its management functions in a standard manner, i.e relying only on Servlet specifications, and transparently, i.e. without demanding source-level dependencies from applications. Overall, SmartGears can bring a wide range of software under the management regime of the e-Infrastructure, without requiring dedicated development. At the same time, it allows new services of the enabling technology to evolve along standard pathways, embracing technologies other than those mandated by gCF.
  • Like SmartGears, the FWS is independent from technologies used by service implementations. The featherweight nature of the stack is in the footprint of its components, which is very small in terms of code, dependencies, and overall usage requirements. Overall, the FWS simplifies the task of clients that wish to interact with any services managed by the e-Infrastructure, gCF-based or SmartGears-based, thereby encouraging uptake.

Overall, the simplifications allowed by gCF have been instrumental to the rapid and consistent growth of the system, reducing significantly administration and development costs for hardware and software resources explicitly allocated to the system or developed for it. The commitment to lightweight integration mechanisms and design modularity in SmartGears and the FWS aligns with modern practices and brings a wider range of resources under the management regime of the e-Infrastructure.

Architecture

The main common libraries are the following:

  • gcf: the gCube Application Framework, a one-stop solution for resource management support and software resource development support;
  • common-smartgears: transparent management support for Servlet-based containers, applications, and services;
  • common-scope: scope handling facilities for policy management;
  • common-validator: annotation-based object validation facilities;
  • common-utils-encryption: encryption and decryption support;
  • common-gcore-resources: object binding of the resource model;
  • common-events: annotation-based eventing support;
  • common-gcore-stubs:client support for JAXWS-based proxies of remote gCF-based services;
  • common-gcube-calls: base layer support for outgoing calls to any infrastructural service;
  • common-jaxws-calls: JAX-WS binding of common-gcube-calls;
  • discovery-client: generic API to formulate and submit queries for resource descriptions.
  • ic-client: extends discovery-client to target the Information Collector service;
  • registry-publisher: support to publish resource description with the Registry service;
  • common-clients: base layer for high leve client libraries to any infrastructural service;
  • common-featherweight-clients: extends common-clients for clients of standard gCF-based services;
  • common-gcube-clients: extends common-clients for clients of SmartGears-enabled services;

Deployment

Common Libraries are a set of facilities available as Java libraries. Therefore, there is no deployment scheme for them. They are just individually and independently co-deployed with components that need to use a particular feature that one of the offers.

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