This project aimed at giving a first taste to students of the world of research in computer science. Doing so by using published paper and implementing the algorithm described in it.
This project aims at creating a decentralized partitioning protocol that guarantees consistent partitioning and termination even in dynamic settings where nodes join and leave the system, create or destroy partitions. This was developed using Spring Boot, it provides a comprehensive programming and configuration model for modern Java-based enterprise applications - on any kind of deployment platform.
Thus, you will find in the project :
- Java class to represent the different instances in a network corresponding to an edge infrastructure.
- A Controller class to handle incoming messages from edge.
- A Service class that implements the AS-cast algorithm as described in the research paper and http service to send data between servers.
- Java 17
- Maven
- For windows for example, you will need to install java 17 and add a JAVA_HOME variable inside your environment path, help here.
- You will need to download and install maven and add the bin folder path to the environment variables.
- Import the project into Intellij for example and launch three different terminal (you can name them B, C, D).
- Open the application.properties file and modify the value of the port, and the serverID, then,
inside each terminal execute the following command :
- mvnw clean package
- mvnw spring-boot:run
- An instance of the project will be launch and will represent a node in the network.
- Once this is done, execute the main.java to launch server A and the tests.
- Be careful to change the values in application.properties whenever you launch a server, otherwise you will encounter PORT and server ID conflicts
- Values tested for the PORT are :
- server A : 8080
- server B : 8081
- server C : 8082
- server D : 8083
- Values tested for the server ID are :
- server A : 1
- server B : 2
- server C : 3
- server D : 4
- If you want to change them, change the test functions
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A controller handles the incoming messages. They are of different types and have each a predefined routes:
- /add_node : this route is used to add a new neighbor to the current server
- /update_weights : this route is used to notify a server when the matrix of weights is updated
- /del_node : this route is used to delete a server from the list of neighbors of the current server
- /add : this route is used when the current server wants to become a source
- /del : this route is used when the current server wants to remove itself as a source
- /receive_add : this route is used when a server wants to propagate an add message to its neighbors
- /receive_del : this route is used when a server wants to propagate a del message to its neighbors
- /on_edge_up : this route is called after a bidirectional link is created between two node, and we need to make them compete together for the best source
- /on_edge_down : this route is called after links are removed between two nodes
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All the requests are POST requests.
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The controller will call the service whenever the controller routes are called and needs to update the state of the node (when becoming a source or receiving new neighbors or new weights). This service implements the AS-Cast algorithm.
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We are using Json to serialize data and by doing so we cannot send a Server instance, and a Message instance at the same time which are needed by the algorithm. To tackle aforementioned problem we use a payload class for each type of message (PayloadMadd and PayloadMDel). Every time a server needs to send a message to its neighbor, the server will create a payload object. Depending on the type of message it will be PayloadMAdd or PayloadMDel. This payload instance will be serialized and sent by http request to every neighbor of the current server. When received, the incoming JSON object is converted to the adequate payload, and we call the AS-Cast algorithm by passing the server and the message.
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To send http request a JSONUtils class and a ServerService class are used. The first one (JSONUtils) is used to transform either JSON to object or objet to JSON. The second one (ServerService) is in charge of creating the http request. All the requests are POST requests.
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The file application.properties is used to specify the PORT of the server that it will listen to. It is also used to specify the server ID. This file needs to be modified when testing are executed.
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At the beginning of the test we generate weights that needs to be sent to every server in order for them to know the same values.