Flask Web Application Setup

1. Install virtualenv, if not already done
2. Create a virtual environment for the application, if needed
3. Activate virtual environment
4. Upgrade pip in virtual environment
5. Install dependencies listed in requirements.txt

Step	Windows (PowerShell)	Linux / MacOS (bash)
1	pip install virtualenv	pip3 install virtualenv
2	python -m venv venv	python3 -m venv venv
3	.\venv\Scripts\Activate.ps1	source venv/bin/activate
4	python -m pip install --upgrade pip	python3 -m pip install --upgrade pip
5	pip install -r requirements.txt	pip install -r requirements.txt

Endpoints to Test

API	Endpoint	Notes
Ping	http://127.0.0.1:5000/ping	JSON: pong
Convert Celcius to Fahrenheit	http://127.0.0.1:5000/convertC/123
Convert Fahrenheit to Celcius	http://127.0.0.1:5000/convertF/--143	Generate Server Error
Validate with Luhn algorithm	http://127.0.0.1:5000/api/luhn/951847623	Masked in logs
Calculate n-th Prime Number	http://127.0.0.1:5000/api/prime/12345	Put load on CPU / RAM
Calculate n-th Fibonacci number	http://127.0.0.1:5000/api/fib/42	JSON result
Calculate n-th Fibonacci number	http://127.0.0.1:5000/extfib/67	Call external service
Get COVID data for Ontario	http://127.0.0.1:5000/covid
Get status for services	http://127.0.0.1:5000/statuspage	AJAX request
Check divisibility of integers	http://127.0.0.1:5000/divisibility

OpenTelemetry

1. To send telemetry data to New Relic, set the following environment variables

   Windows (PowerShell)

   $Env:OTEL_EXPORTER_OTLP_ENDPOINT="https://otlp.nr-data.net:4317"
   $Env:OTEL_EXPORTER_OTLP_HEADERS=api-key="XXXX...NRAL"
   $Env:OTEL_RESOURCE_ATTRIBUTES=service.name="python-flask.otel,service.instance.id=localhost-pc"

   Linux / macOS

   export OTEL_EXPORTER_OTLP_ENDPOINT="https://otlp.nr-data.net:4317"
   export OTEL_EXPORTER_OTLP_HEADERS="api-key=XXXX...NRAL"
   export OTEL_RESOURCE_ATTRIBUTES=service.name="python-flask.otel,service.instance.id=vercel"

2. Download the following packages to your virtual environment

   pip install opentelemetry-exporter
   pip install opentelemetry-instrumentation-flask
   pip install opentelemetry-instrumentation-jinja2
   pip install opentelemetry-instrumentation-requests
   

3. No changes to the code is needed, just run the app as usual but with opentelemetry-instrument at the front

   opentelemetry-instrument python webserver.py
   

Docker Image

1. Build the Docker image with docker build -t python-flask:latest .
2. Run the app with your environment variables and give your application a name:

   docker run -d --name python-flask -e OTEL_EXPORTER_OTLP_ENDPOINT="https://otlp.nr-data.net:4318" -e OTEL_EXPORTER_OTLP_HEADERS="api-key=XXXX...NRAL" -e OTEL_RESOURCE_ATTRIBUTES="service.name=python-flask.otel,service.instance.id=docker,tags.environment=production,tags.team=datacrunch" -p 5000:5000 python-flask:latest
   

3. Access the application with the same endpoints above at http://127.0.0.1:5000