Implementation of a server/client application in Java RMI and JavaFX to manage concurrent connections for managing a file system that accepts operations on users' text files.
The project name is shorted as DTFS (Distributed Text File System) so it
can be used into the source code, for example: domain module dtfs, main
package engineer.mathsoftware.cp.dtfs, etc.
The original course project required a much simpler implementation, and the main objective was to apply DevOps skills. Needless to say, as I often do, I have added a huge amount of extra value to this project to make it worth it. My objectives are to keep working on some new features after the initial release and build good DevOps documentation. Additionally, it's a good chance to show good use cases of the main underlying technologies: Java and JavaFX.
- Java RMI or Python Pyro only.
- Anything that works for the client.
- Linux containers.
This system can be deployed in several ways. According to the course topics, you should use linux containers for the server applications. For this server, there are two applications that run the distributed system:
-
RMI Registry: Receives the request from clients to connect to the remote object from the file server.
-
RMI File System Server: Manages the actual file system and physical files in storage. The clients access the remote object of this application through the RMI Registry, so the registry may be deployed separately from the server storing the actual files.
On the other side, for the client application you should run three or more of them to show the real time functionality.
One way to deploy all the system is as a standalone fashion. This way you need tons of RAM to run many VMs, JVMs, Linux Containers and other open applications as depicted by the following diagram:
In that case, I would even suggest trying to use GraalVM to avoid that crazy amount of JVMs. That is something I haven't tested yet and the project at this stage is quite unstable. GraalVM also doesn't play well with the latest non-LTS Java versions and just properly deploying JavaFX is a bit of a mess by itself these days mostly if you use the latest versions of tools prior waiting for issue fixes.
So let's keep that game for later with Java 17 LTS since I am also
using JDK 16 + --enable-preview as a good mathematician to take advantage of
the new data oriented and FP features for the model (or domain) layer.
Now I've moved the project forward to Java 17 (still with preview features) so I expect that the ultimate version of this project will run with Java 21 LTS or later.
For this version of the software, you need to do some manual configs regarding IP addresses or hostnames. This is because the RMI technology requires knowing not only the server hostname where the JVM is running but also the client's hostname to answer back to it. If the hostname property isn't set on the client app then the server won't be able to respond to that client, or it might take a huge amount of time to respond. Fortunately, everything is set up already, and the config process just requires a bit of work.
Check Deployment for info while this section is updated with a dead simple test environment.
In this article, I talk about an experience I had with the famous binary compatibility. This happens when you update a software (library, etc.) to other version with binary breaking changes. For instance, changing a method signature; in that case, all the library clients have to recompile their classes and if they had serialized and persisted objects of that class then we got troubles.
One of the main issue of v0.1.0 is the local FS update regarding deleting
files. When a user deletes a file form the system, it's physically deleted from
the user machine but not physically deleted from the other client machines. This
feature will be implemented in a further project version. Significant
performance optimizations will be scheduled for later releases too.
Go to the deployment documentation.
LXC and Registry Container
LXC and FS container
Client running and FS Server files
Demo Animation
This project: Docs , Repository
Tobias Briones: GitHub
Course Project at UNAH-MM545: Distributed Text File System
Implementation of a server/client application in Java RMI and JavaFX to manage concurrent connections for managing a file system that accepts operations on users' text files.
Copyright © 2021-2022 Tobias Briones. All rights reserved.
This project implementation is licensed under the BSD 3-Clause License.
This project's original specification is provided "AS IS" at ./docs/course.