UdaConnect

Overview

Background

Conferences and conventions are hotspots for making connections. Professionals in attendance often share the same interests and can make valuable business and personal connections with one another. At the same time, these events draw a large crowd and it's often hard to make these connections in the midst of all of these events' excitement and energy. To help attendees make connections, we are building the infrastructure for a service that can inform attendees if they have attended the same booths and presentations at an event.

Goal

You work for a company that is building a app that uses location data from mobile devices. Your company has built a POC application to ingest location data named UdaTracker. This POC was built with the core functionality of ingesting location and identifying individuals who have shared a close geographic proximity.

Management loved the POC so now that there is buy-in, we want to enhance this application. You have been tasked to enhance the POC application into a MVP to handle the large volume of location data that will be ingested.

To do so, you will refactor this application into a microservice architecture using message passing techniques that you have learned in this course. It’s easy to get lost in the countless optimizations and changes that can be made: your priority should be to approach the task as an architect and refactor the application into microservices. File organization, code linting -- these are important but don’t affect the core functionality and can possibly be tagged as TODO’s for now!

Technologies

• Flask - API webserver
• SQLAlchemy - Database ORM
• PostgreSQL - Relational database
• PostGIS - Spatial plug-in for PostgreSQL enabling geographic queries]
• Vagrant - Tool for managing virtual deployed environments
• VirtualBox - Hypervisor allowing you to run multiple operating systems
• K3s - Lightweight distribution of K8s to easily develop against a local cluster

Running the app

The project has been set up such that you should be able to have the project up and running with Kubernetes.

Prerequisites

We will be installing the tools that we'll need to use for getting our environment set up properly.

1. Install Docker
2. Set up a DockerHub account
3. Set up kubectl
4. Install VirtualBox with at least version 6.0
5. Install Vagrant with at least version 2.0

Environment Setup

To run the application, you will need a K8s cluster running locally and to interface with it via kubectl. We will be using Vagrant with VirtualBox to run K3s.

Initialize K3s

In this project's root, run vagrant up.

$ vagrant up

The command will take a while and will leverage VirtualBox to load an openSUSE OS and automatically install K3s. When we are taking a break from development, we can run vagrant suspend to conserve some ouf our system's resources and vagrant resume when we want to bring our resources back up. Some useful vagrant commands can be found in this cheatsheet.

Set up kubectl

After vagrant up is done, you will SSH into the Vagrant environment and retrieve the Kubernetes config file used by kubectl. We want to copy the contents of this file into our local environment so that kubectl knows how to communicate with the K3s cluster.

$ vagrant ssh

You will now be connected inside of the virtual OS. Run sudo cat /etc/rancher/k3s/k3s.yaml to print out the contents of the file. You should see output similar to the one that I've shown below. Note that the output below is just for your reference: every configuration is unique and you should NOT copy the output I have below.

Copy the contents from the output issued from your own command into your clipboard -- we will be pasting it somewhere soon!

$ sudo cat /etc/rancher/k3s/k3s.yaml

apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: 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
    server: https://127.0.0.1:6443
  name: default
contexts:
- context:
    cluster: default
    user: default
  name: default
current-context: default
kind: Config
preferences: {}
users:
- name: default
  user:
    password: 485084ed2cc05d84494d5893160836c9
    username: admin

Type exit to exit the virtual OS and you will find yourself back in your computer's session. Create the file (or replace if it already exists) ~/.kube/config and paste the contents of the k3s.yaml output here.

Afterwards, you can test that kubectl works by running a command like kubectl describe services. It should not return any errors.

Steps

1. kubectl apply -f deployment/db-configmap.yaml - Set up environment variables for the pods
2. kubectl apply -f deployment/db-secret.yaml - Set up secrets for the pods
3. kubectl apply -f deployment/postgres.yaml - Set up a Postgres database running PostGIS
4. kubectl apply -f deployment/udaconnect-api.yaml - Set up the service and deployment for the API
5. kubectl apply -f deployment/udaconnect-app.yaml - Set up the service and deployment for the web app
6. sh scripts/run_db_command.sh <POD_NAME> - Seed your database against the postgres pod. (kubectl get pods will give you the POD_NAME)

Manually applying each of the individual yaml files is cumbersome but going through each step provides some context on the content of the starter project. In practice, we would have reduced the number of steps by running the command against a directory to apply of the contents: kubectl apply -f deployment/.

Note: The first time you run this project, you will need to seed the database with dummy data. Use the command sh scripts/run_db_command.sh <POD_NAME> against the postgres pod. (kubectl get pods will give you the POD_NAME). Subsequent runs of kubectl apply for making changes to deployments or services shouldn't require you to seed the database again!

Microservices: There are 6 microservies alltogether which need to be deployed in the following order:

KAFKA:

In order to start this service, go to kafka folder inside modules and run the following command: kubectl apply -f deployment/

Location Service

In order to start this service, go to location service inside modules and run the following command:

kubectl apply -f deployment/

Location Cosumer Service

In order to start this service, go to location consumer service inside modules and run the following command:

kubectl apply -f deployment/

Person Service

In order to start this service, go to person service inside modules and run the following command:

kubectl apply -f deployment/ Please make sure to run the script to insert the initial records by executing kubectl exec -it --sh script/run_db_command.sh

Connection Service

In order to start this service, go to connection service folder inside modules and run the following command: kubectl apply -f deployment/

Please make sure to run the script to insert the initial records by executing kubectl exec -it --sh script/run_db_command.sh

Frontend app

In order to start this service, go to frontend folder inside modules and run the following command: kubectl apply -f deployment/ open the browser and type: http://localhost:30000

Architecture Diagrams

udaconnect/modules/diagram.png

Some popular free software and tools to create architecture diagrams:

1. Lucidchart
2. Google Docs Drawings (In a Google Doc, Insert - Drawing - + New)
3. Diagrams.net

• We can access a running Docker container using kubectl exec -it <pod_id> sh. From there, we can curl an endpoint to debug network issues.
• The starter project uses Python Flask. Flask doesn't work well with asyncio out-of-the-box. Consider using multiprocessing to create threads for asynchronous behavior in a standard Flask application.