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Platform Team/Sugar Network/Architecture (view source)

Revision as of 23:42, 26 November 2012

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This page is an overview of technical implementation of the Sugar Network. See also the [[Sugar_Network|introduction page]] and the [[Sugar_Network/Concept|basic concepts overview]].
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This is a twin page of Sugar Network's [[Sugar_Network/Concept|basic concepts]] from technical point of view. See also the [[Sugar_Network|introduction page]].
    
== Overview ==
 
== Overview ==
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* Clients create, modify and browse different types of resources ([[Sugar_Network/Concept#Resources|resources]] from conceptual point of view, [[Platform_Team/Sugar_Network/API#Resources|resources]] from the API point of view) on a server;
 
* Clients create, modify and browse different types of resources ([[Sugar_Network/Concept#Resources|resources]] from conceptual point of view, [[Platform_Team/Sugar_Network/API#Resources|resources]] from the API point of view) on a server;
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* If this server is a [[#Distributed_servers|distributed]] one, the system will take care about [[#Synchronisation|synchronizing]] its resources with other distributed servers and, finally, with the central one, the [[#Mothership|Mothership]].
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* If this server is a [[#Node_servers|Node]] server, the system will take care about [[#Synchronization|synchronizing]] its resources with other Node servers and, finally, with the central one, the [[#Master_server|Master]] server.
    
=== Components ===
 
=== Components ===
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This is technical view on [[Sugar_Network/Concept#Overview|three levels]] of the Sugar Network:
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* [[#Server|Server side]],
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* [[#Conceptual_level|Conceptual level]],
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* [[#Client|Client side]].
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== Server ==
    
[[File:Sugar-networks-architecture.png|right]]
 
[[File:Sugar-networks-architecture.png|right]]
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The Sugar Network consists of different types of components:
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Server side is represented by:
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* [[#Server|Server side]] that provide [[Platform_Team/Sugar_Network/API|API]] for clients:
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* [[#Master_server|Master]] server that keeps the whole Sugar Network information, clients might connect directly to this server (on-line case) or indirectly via Node servers (off-line case);
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** [[#Mothersip|Mothership]] server that keeps the whole Sugar Network information, clients might connect directly to this server (on-line case) or indirectly via distributed servers (off-line case);
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* Optional [[#Node_servers|Node]] servers, contain a [[#Synchronization|synchronised]] copy of central server (might be not for the entire Network to save storage space);
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** Optional [[#Distributed_servers|distributed servers]], contain a [[#Synchronisation|synchronised]] copy of central server (might be not for the entire Network to save storage space);
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* [[#Client|Client side]]:
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** Client application that uses [[Platform_Team/Sugar_Network/API|API]] to interact with a server;
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** Client application that [[#Personal_server|provides]] limited [[Platform_Team/Sugar_Network/API|API]] to support server-less workflow.
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== Server ==
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In all cases the server [[Platform_Team/Sugar_Network/API|API]] is the same for clients. But depending on connectivity, clients might be connected to the [[#Master_server|Master]] server or to a [[#Node_servers|intermediate server]].
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In all cases the server [[Platform_Team/Sugar_Network/API|API]] is the same for clients. But depending on connectivity, clients might be connected to the [[#Mothership|Mothership]] or to an [[#Distributed_servers|intermediate server]].
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=== Master server ===
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=== Mothership ===
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The place where data is being collected from all Node servers. If clients have connectivity, they can connect to the Master to contribute to the Network directly.
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The place where data is being collected from all distributed server. If clients have connectivity, they can connect to the Mothership to contribute to the Network directly.
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=== Node servers ===
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=== Distributed servers ===
      
Servers that will be useful if:
 
Servers that will be useful if:
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* connectivity is not cheap and its usage needs to be minimized.
 
* connectivity is not cheap and its usage needs to be minimized.
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Distributed services provide full featured [[Platform_Team/Sugar_Network/API|API]] as the Mothership does. Distributed servers need to be [[#Synchronisation|synchronized]].
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Node servers provide full featured [[Platform_Team/Sugar_Network/API|API]] as the Master does. Nodes need to be [[#Synchronization|synchronized]].
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=== Synchronisation ===
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== Conceptual level ==
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To let Network participant, connected to particular [[#Distributed_servers|distributed server]], interact with people from another distributed servers or with people from the Internet, distributed servers need to be synchronized.
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This is how Sugar Network looks like on [[Sugar_Network/Concept|conceptual level]] represented by the [[Platform_Team/Sugar_Network/API|API]].
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Server might be synchronised:
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=== Objects model ===
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* With the Mothership, if connectivity presents;
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{{:Platform_Team/Sugar_Network/Objects_model}}
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* With the Mothership or any other distributed servers via the [[Wikipedia:Sneakernet|Sneakernet]].
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== Client ==
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The model refers to the following additional information:
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=== Simplified editing workflow ===
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The system is designed to be as lightweight as possible to make it running on XO laptops in unmaintainable environments and simplify synchronization. So, the following design decisions were taken:
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* No history for Sugar Network objects, only events about made changes;
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* Only object author(s) can process editing;
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* But, other people can suggest changes (that might be implemented on client side in pretty powerful way, e.g., people can change objects but it will be postponed for later author(s)' review).
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Client application is local, for reasons:
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That might be changed but only after making system one level more complicated.
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* Originally, Sugar Network was being developed for deployments where teachers' XOs will be distributed servers, thus, it will be useful to delegate some of computing to students' XOs;
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== Client ==
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* Stimulate doing behaviour when it should be possible to create new client application or tweak existing on a client side;
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* It is all time possible to create Web application on a server side.
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=== Default client ===
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This is what Network participants are interacting with. This is a software that let people get access to the Sugar Network and define how Sugar Network should look like from users point of view. User experience, that these clients provide, might be too different from a client to a client. Starting from a couple of elements in the already existing software's [[Wikipedia:Graphical_user_interface|GUI]] (when people even don't suspect they are interacting with the Sugar Network) and ending with clients that represent conceptual level as close as possible.
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The default client is implemented using Web technologies to:
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Client side is represented by:
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* Using Web technologies might make client developing easier;
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* Client application that uses [[Platform_Team/Sugar_Network/API|API]] to interact with a server;
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* Make it possible to reuse Sugar Network in any Web browser in any Desktop Environment, i.e., not only from Sugar Shell;
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* Client application that [[#Personal_server|provides]] limited [[Platform_Team/Sugar_Network/API|API]] to support server-less workflow.
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* It might be easier to find potential Sugar contributors within Web developers rather than developers who know GTK.
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It might sound a bit confusing to have local Web application, but this decision is based on:
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Client application is local, for reasons:
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* Local Web applications serve only one user and are much simpler than singular applications that are intended to serve multiple users simultaneously;
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* Originally, Sugar Network was being developed for deployments where teachers' XOs will be Node servers, thus, it will be useful to delegate some of computing to students' XOs;
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* It might be useful to design simple and clean code using existing Web technics like MVC;
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* Stimulate doing behaviour when it should be possible to create new client application or tweak existing on a client side;
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* Thus, it will be easier for doers to learn, change, reimplement the new clients.
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* It is all time possible to create Web application on a server side.
    
=== Personal server ===
 
=== Personal server ===
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* Private data in user's home directory,
 
* Private data in user's home directory,
 
* Data accessible from removable devices like USB sticks or SD cards.
 
* Data accessible from removable devices like USB sticks or SD cards.
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== Synchronization ==
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To let Network participant, connected to particular [[#Node_servers|Node server]], interact with people from another Node servers or with people from the Internet (Master server), Node servers need to be synchronized.
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Server might be synchronized:
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* With the Master, if connectivity presents;
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* With the Master or any other Node servers via the [[Wikipedia:Sneakernet|Sneakernet]].
    
== Getting involved ==
 
== Getting involved ==
Retrieved from "https://wiki.sugarlabs.org/go/Special:MobileDiff/73466...84354"

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