sentinel-server-assignment.md

Heart Rate Sentinel Server

This assignment will have you build a simple centralized heart rate sentinel server. This server will be built to receive POST requests from mock patient heart rate monitors that contain patient heart rate information over time. If a patient exhibits a tachycardic heart rate, the physician should receive an email warning them. So if a new heart rate is received for a patient that is tachycardic, the email should be sent out at that time. This calculation should be based on age (more info here). This can be sent using the free Sendgrid API (there is also a Sendgrid python package that wraps the API).

Name your repository: heart_rate_sentinel_server. Note: for this assignment, you do not have to use a database. You can choose to store patient information using in memory data structures like python lists and dictionaries.

Your Flask web service should implement the following API routes:

• POST /api/new_patient with

  {
      "patient_id": "1", # usually this would be the patient MRN
      "attending_email": "suyash.kumar@duke.edu", 
      "user_age": 50, # in years
  }

  This will be called when the heart rate monitor is checked out to be attached to a particular patient, the system emits this event to register the patient with your heart rate server. This will allow you to initialize a patient, and accecpt future heart rate measurements for this patient.
• POST /api/heart_rate with

  {
      "patient_id": "1", # usually this would be the patient MRN
      "heart_rate": 100
  }

  which should store this heart rate measurement for the user with that email. Be sure to include the current time stamp in your database or your program cache.
• GET /api/status/<patient_id> should return whether this patient is currently tachycardic based on the previously available heart rate, and should also return the timestamp of the most recent heart rate.
• GET /api/heart_rate/<patient_id> should return all the previous heart rate measurements for that patient
• GET /api/heart_rate/average/<patient_id> should return the patients's average heart rate over all measurements you have stored for this user.
• POST /api/heart_rate/interval_average with

  {
      "patient_id": "1",
      "heart_rate_average_since": "2018-03-09 11:00:36.372339" // date string
  }
  

For this assignment, be sure to write modular code. This means your handler functions for routes should be calling other independent functions in different modules as frequently as possible. All of those other independant functions should be tested. You should also remember to validate user inputs that come from (request.get_json()) to ensure the right fields exist in the data and that they are the right type. You can write independant, testable validate_heart_rate_request(r) functions. You do not have to test the flask handler functions directly (the functions associated with the @app.route decorator), but all other functions should be tested.

Submission Notes

• As always in this class, be sure to follow all best practice conventions (unit testing, git practices, Travis CI, testing, PEP8, docstrings, etc)
• Please git tag the final version of your repository as done previously in this class
• Ensure your repository is called heart_rate_sentinel_server
• The SendGrid part of this assignment will not be worth the majority of points, so focus on that part after the rest of the functionality has been completed.
• Please deploy this on your VCM and submit the hostname and port that your server is running on to the Sakai assignment posting (vcm-1000.vm.duke.edu:5000). Remember to follow the emailed instructions about ensuring your server does not restart (there is a check box on the vcm control panel. It will ask you for a reason, just say you are running a web server assignment for BME590 Medical Software Design). Please do this deployment step last, it is most important to complete the rest of the assignment first (that is where most of the points are).

More information about SendGrid

You need to create a free account at sendgrid.com and then create an API key which is a key that authenticates you to use the SendGrid API. Note that SendGrid has a nice python API that you can install using pip. In the example code shown there, you need to set the SENDGRID_API_KEY environment variable to your API key you created earlier. Try not to commit your key to github as that will expose it for others to use.

Special note for Mac users

👀 Apparently python 3.6 for Mac does not come configured to use the standard root certificate authorities, so some folks may get a ssl error when using the SendGrid client. To fix this, run the following command:

/Applications/Python\ 3.6/Install\ Certificates.command

If you installed Python 3.7, change 3.6 to 3.7 in the command above.

If you're getting an error like this in conda, try

conda remove certifi
conda install certifi