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versioned_docs/version-1.2/The Backend Implementation/1-action_flow.md
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# Action Flow | ||
<br/> | ||
<p align="center"> | ||
![architecture diagram](../../../static/img/backend.png) | ||
</p> | ||
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<p align="center"> | ||
The Backend technologies and their connections. | ||
</p> | ||
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--- | ||
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<!-- START doctoc generated TOC please keep comment here to allow auto update --> | ||
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE --> | ||
## Table of Contents | ||
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- [Action Flow](#action-flow) | ||
- [Table of Contents](#table-of-contents) | ||
- [General Flow Description](#general-flow-description) | ||
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<!-- END doctoc generated TOC please keep comment here to allow auto update --> | ||
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--- | ||
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## General Flow Description | ||
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The **backend** is composed of multiple services and technologies that manage **three internal functions**: | ||
- **Load Balancing** | ||
- **Data Manipulation** | ||
- **Data Persistance** | ||
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The **data** is provided in the form of **HTTP requests** created by the **frontend** of the application. | ||
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These requests are first intercepted by the **load balancer**, which will distribute all the incoming requests to a set of **API instances**. | ||
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These instances will perform the necessary **data processing** and analysis and will provide the response back to the load balancer, which will promptly **foward the response** back to the initial **requester**. | ||
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To **persist** and save the **data**, the API instances are connected to a set of **three main databases**. | ||
Each database has a **distinct function**, that being for saving the **data models** (main database), saving the **provided files** (cloud storage) and finally saving the **configurations** of the instances and "magic numbers" (configuration database) |
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versioned_docs/version-1.2/The Backend Implementation/2-load_balancer.md
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# Load Balancer | ||
<br/> | ||
<p align="center"> | ||
![architecture diagram](../../../static/img/nginx.png) | ||
</p> | ||
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--- | ||
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<!-- START doctoc generated TOC please keep comment here to allow auto update --> | ||
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE --> | ||
## Table of Contents | ||
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- [Load Balancer](#load-balancer) | ||
- [Table of Contents](#table-of-contents) | ||
- [NGINX](#nginx) | ||
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<!-- END doctoc generated TOC please keep comment here to allow auto update --> | ||
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--- | ||
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## NGINX | ||
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For the **load balancer**, we chose to use a simple [**NGINX**](https://nginx.org/en/) configuration, that allows us to tune how the **distribution of work** is made between the **API instances** (round-robin, response time, etc) and does not introduce a large processing **overhead** into our system. | ||
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Since the system is **user-based**, the backend must provide the responses in a **timely manner**, so any overhead introduced must be reduced to a minimum. | ||
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NGINX also allows us to automatically **intercept and filter large files** as soon as the requests carrying them are received in the backend, preventing these files from taking up too much processing power to analyze. | ||
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So with NGINX we can: | ||
* **Balance the processing load** more efficiently across our API Instances; | ||
* **Prevent large files** from having to be processed, discarding them as soon as possible; | ||
* **Reduce the overhead** introduced into the system by other large load balancers. |
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versioned_docs/version-1.2/The Backend Implementation/3-api_Instances.md
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# API Instances | ||
<br/> | ||
<p align="center"> | ||
![architecture diagram](../../../static/img/python_fastapi.png) | ||
</p> | ||
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--- | ||
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<!-- START doctoc generated TOC please keep comment here to allow auto update --> | ||
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE --> | ||
## Table of Contents | ||
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- [API Instances](#api-instances) | ||
- [Table of Contents](#table-of-contents) | ||
- [Why Python and FastAPI](#why-python-and-fastapi) | ||
- [The FastAPI implementation](#the-fastapi-implementation) | ||
- [Endpoints](#endpoints) | ||
- [Models](#models) | ||
- [Repositories](#repositories) | ||
- [Utils](#utils) | ||
- [Templates](#templates) | ||
- [Tests](#tests) | ||
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<!-- END doctoc generated TOC please keep comment here to allow auto update --> | ||
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--- | ||
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## Why Python and FastAPI | ||
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For the API itself, we chose to use [**FastAPI**](https://fastapi.tiangolo.com/). | ||
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This choice was heavily influenced by the fact that **all the code must be extremely well documented** and easy to change in the future. | ||
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FastAPI also provides **more functionality** than some of its more "barebones" competitors (for example, **flask**), while **omitting most of the less used features** of more complex alternatives (for example, **django**). | ||
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The option of creating a **Spring-based API** or choosing a programming language **other than Python** is not possible, as the code itself **must be able to be maintained** by people who may not have the specific knowledge to quickly apply the changes that might be needed in the future. | ||
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**Future proofing** also had a large impact on our decision, as all the components of this project must be able to have perhaps even **decades of support**, since if just one of the components used is discontinued, the whole action flow will be disrupted, causing **problems in the whole pipeline**. | ||
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Therefore, **Python** and **FastAPI** were chosen because of their **featuresets**, easy **maintainability**, relatively **proven** future, and good **performance**. | ||
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--- | ||
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## The FastAPI implementation | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/fastapi.png) | ||
</p> | ||
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The final API codebase was divided into **multiple subsections**: | ||
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--- | ||
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### Endpoints | ||
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The endpoints consist of all the **accessible functions of the API**, along with their parameters and responses. | ||
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All the endpoint's documentation can be found on the **Swagger documentation** on the API itself, at [**localhost:8080/docs**](localhost:8080/docs) (the application must be on in order for this page to work). | ||
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The endpoints consist of **CRUD** and **other functions** that operate on the **models** and **local files** that have been inserted into the backend. | ||
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--- | ||
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### Models | ||
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The models are the **Python/Database** representation of the **real-life objects** that we are working with, providing a simpler and more clear approach to **data manipulation**. | ||
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There are multiple models, for example: | ||
- **User** Model; | ||
- **Dissertation** Model; | ||
- **Notification** Model; | ||
- etc. | ||
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Using the [**pydantic**](https://pydantic.dev/) library, all the models automatically apply **data consistency checks**, valid value checks, **default values**, etc for all the parameters and variables stored inside a given model object, allowing for a much **easier and cleaner code** implementation. | ||
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--- | ||
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### Repositories | ||
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For **interacting with the main database**, a set of repository actions was implemented that allow the **abstraction** of the database components in the rest of the application. | ||
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These repositories apply the necessary database operations to the main Database given a set of predefined parameters, and respond with the semi-processed outcome of the database. | ||
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These are essential to **ensure that the database is not overloaded** with bad requests from other functions, that the database threads are used **efficiently** and that access to the database is **easy to alter**. | ||
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--- | ||
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### Utils | ||
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The utils are a set of functions that provide **extended functionality** to other parts of the API. | ||
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These functions include: | ||
- **Authenticating** users; | ||
- Creating and sending **email notifications**; | ||
- Getting the **configurations** from the Configuration Database; | ||
- Managing **local files** from the Filesystem; | ||
- etc. | ||
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--- | ||
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### Templates | ||
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These templates are used by [**Jinja**](https://jinja.palletsprojects.com/en/3.1.x/) and the API to **generate simple HTML code**. | ||
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The generated file can then be sent to an **email notification** or used to **list all the data collected** throughout the year (useful for collecting information from the previous year for backups). | ||
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--- | ||
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### Tests | ||
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The test portion is still to be implemented. |
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versioned_docs/version-1.2/The Backend Implementation/4-databases.md
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# Databases | ||
<br/> | ||
<p align="center"> | ||
![architecture diagram](../../../static/img/databases_nobg.png) | ||
</p> | ||
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<p align="center"> | ||
The database technologies utilized | ||
</p> | ||
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--- | ||
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<!-- START doctoc generated TOC please keep comment here to allow auto update --> | ||
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE --> | ||
## Table of Contents | ||
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- [Databases](#databases) | ||
- [Table of Contents](#table-of-contents) | ||
- [Databases](#databases-1) | ||
- [Main Database](#main-database) | ||
- [File Storage](#file-storage) | ||
- [Configuration Database](#configuration-database) | ||
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<!-- END doctoc generated TOC please keep comment here to allow auto update --> | ||
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--- | ||
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## Databases | ||
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For better **separation, maintainability, scalability and performance**, the persistence of data was divided into **three separate databases**. | ||
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This allows the better utilization of each database's **core strengths** as they are needed in the multitude of tasks that the **API Instances** are required to perform. | ||
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--- | ||
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### Main Database | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/mongodb.png) | ||
</p> | ||
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The **models** mentioned previously as well as most of the data processed are **saved in the Main Database**. | ||
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Due to the **volatile** and **highly customizable** nature of these models, a database that could easily be adapted to new model formats was necessary. | ||
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This means that the typical SQL databases are **not adequate** for our type of data structures, so a **[NoSQL](https://en.wikipedia.org/wiki/NoSQL) database was chosen instead**. | ||
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Most NoSQL databases are much more recent than the SQL databases we are used to, and since all the components in this project must have certified **long term support**, the **[MongoDB](https://www.mongodb.com/) database was chosen**. | ||
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MongoDB allows the **models to be changed without affecting the compatibility of old data models**, meaning that changes made to the database will still always allow for old data to be processed along with new data. | ||
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Another key feature that drove our decision is the ability to easily convert a **mongoDB document into a JSON object** that could easily be natively worked on inside our python codebase, **without the need for complicated operations** such as joins, aggregations, etc... | ||
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--- | ||
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### File Storage | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/cloud_storage.png) | ||
</p> | ||
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**Storing large files** (ex: PDF files from dissertations or dissertation logos) would take a lot of **I/O throughput** away from the rest of the Main Database as well as use a lot of the machine's available **storage space**. | ||
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This means that another way of storing large singular files had to be chosen. | ||
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For this, we used a **cloud storage system** that is included inside the machine's filesystem, which is then linked inside the necessary **docker volumes**. | ||
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This allows the asynchronous storage and retrieval of files **without impacting the Main Database's** throughput capacity or performance. | ||
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--- | ||
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### Configuration Database | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/mariadb.png) | ||
</p> | ||
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Since **there can be a lot of API Instances running at any given time**, changes made to the configuration must be made in such a way that all the instances must pick up the new changes as soon as they use them. | ||
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So for **configurations and "magic numbers"**, we had to implement a place where all the instances could reach and get the necessary values. | ||
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To do this, we chose to add a **[MariaDB](https://mariadb.org/) implementation** so that we did not have to worry about **concurrency** between all the instances and the data changes, as well as allowing all the configuration data to be **stored in the same, easy to edit file**. |
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versioned_docs/version-1.2/The Backend Implementation/5-docker_kubernetes.md
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# Docker And Kubernetes | ||
<br/> | ||
<p align="center"> | ||
![architecture diagram](../../../static/img/docker_all.png) | ||
</p> | ||
|
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<p align="center"> | ||
The containarization technologies utilized | ||
</p> | ||
|
||
--- | ||
|
||
<!-- START doctoc generated TOC please keep comment here to allow auto update --> | ||
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE --> | ||
## Table of Contents | ||
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- [Docker And Kubernetes](#docker-and-kubernetes) | ||
- [Table of Contents](#table-of-contents) | ||
- [Docker Compose](#docker-compose) | ||
- [Docker Containers](#docker-containers) | ||
- [Docker Networks](#docker-networks) | ||
- [Docker Volumes](#docker-volumes) | ||
- [Kubernetes](#kubernetes) | ||
|
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<!-- END doctoc generated TOC please keep comment here to allow auto update --> | ||
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--- | ||
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## Docker Compose | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/docker-compose.png) | ||
</p> | ||
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[Docker Compose](https://docs.docker.com/compose/) was used as the primary **container orchestrator**. | ||
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Docker Compose allows us to define all the necessary deployment parameters, such as **ports**, **volumes** and image **versions**. | ||
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It also allows us to **manage**, **launch** and **stop** all the containers at once. | ||
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--- | ||
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### Docker Containers | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/docker.png) | ||
</p> | ||
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For the dockerization of our application, the following containers were defined: | ||
- **Application** (frontend) | ||
- **Api Instance** (multiple can be created at once) | ||
- **Load Balancer** | ||
- **MongoDB** | ||
- **MariaDB** | ||
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--- | ||
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### Docker Networks | ||
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Another advantage of docker compose is the ability to create multiple **separate networks between containers**. | ||
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In our application the following networks were created: | ||
- **frontend_network** (App ⇄ Frontend Server) | ||
- **backend_network** (API Instances ⇄ Databases) | ||
- **request_network** (Load Balancer ⇄ API Instances) | ||
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--- | ||
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### Docker Volumes | ||
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Both MongoDB and the Cloud Service require the use of volumes, and the Cloud Service's volume must be **mapped to the host's filesystem** (bind volume). | ||
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In our application the following volumes were created: | ||
- **mongodbdata** (MongoDB Data) | ||
- **file-bind** (Bind volume that utilizes the host's filesystem, which is then managed by the cloud server) | ||
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--- | ||
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## Kubernetes | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/kubernetes.png) | ||
</p> | ||
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A [Kubernetes](https://kubernetes.io/) implementation was **partially implemented**, but would require more work to be put into it in order to be production ready. | ||
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The specific kubernetes distribuition used was the simpler [K3s](https://k3s.io/), providing all the required functionality at a smaller cost of setup time. | ||
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Since the final production environment will only consist of a **single server**, the kubernete's main feature of load balancing between machines would not be of any use. | ||
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The ability to **detect crashes on containers** and **relaunch the affected service(s)** is very useful to our application, but more discussion needs to be had in order to determine if this is a priority for our system. | ||
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The final production version will include a **kubernetes file** which will launch the containers and do the appropriate load balancing, but more **testing must be done** in order to apply the changes to production. |
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# Architecture | ||
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## Architecture Diagram | ||
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A simple diagram to illustrate our architecture | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/architecture.png) | ||
</p> |
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# Deployment | ||
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## Deployment and Structural Diagram | ||
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A simple deployment diagram and infrastructure mapping | ||
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<p align="center"> | ||
![architecture diagram](../../../static/img/deployment.png) | ||
</p> |
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