chalice-gis-demo

A reference implementation of a REST-exposed GIS server using AWS Lambda functions generated using Chalice. Includes AWS features such as RDS (for the PostgreSQL database), Lambda (for the FaaS modules), API Gateway for handling requests and responses, VPC (Virtual Private Cloud) which enables proper performance between Lambda and RDS. It is a proof-of-concept and a demo of how one can implement a FaaS GIS server into AWS. It is not meant to be a robust, production-quality solution, but rather an example and potential starting point for future projects.
Article describing this proof-of-concept: Create a FaaS REST GIS in AWS using Open Source Tools
Lambda framework: Chalice
Database: PostgreSQL
- Based on restaurant inspection data, from several years ago (circa 2013), collected by the state of New York and shared at the USA government website data.gov
  - This is publicly available information published by the US government.
- The backend database for this demo does not include PostGIS at this time.
- Contains a flat table named restaurants--not a normalised database, for simplicity of the demo.
Connection to database: psycopg2
Circle distance calculation uses the libraries geographiclib and geopy

Interfaces

At this time, the interfaces are GET (read-only) actions, especially since the proof-of-concept is being publicly hosted.
The documentation for Chalice framework includes information on how to include other REST operations such as POST, PUT, and DELETE

Select top (limit) of items /restaurants/limit/{limit} eg: https://a4fpsm6md0.execute-api.us-east-1.amazonaws.com/api/restaurants/limit/100
Select by object ID /restaurants/oid/{oid} eg: https://a4fpsm6md0.execute-api.us-east-1.amazonaws.com/api/restaurants/oid/1441071
Select by circle (items within the circle), with parameters latitude, longitude, and radius in km /restaurants/circle/{circle} eg: https://a4fpsm6md0.execute-api.us-east-1.amazonaws.com/api/restaurants/circle/43.1009,-75.2327,150.5
Select by bounding box (items within bounding box), with parameters upper left latitude, upper left longitude, lower right latitude, lower right longitude /restaurants/bbox/{bbox} eg: https://a4fpsm6md0.execute-api.us-east-1.amazonaws.com/api/restaurants/bbox/43.000000,-79.000000,41.000000,-71.000000
Select by facility (restaurant) name /restaurants/facility/{facility} eg: https://a4fpsm6md0.execute-api.us-east-1.amazonaws.com/api/restaurants/facility/LITTLE%20ROMA%20PIZZA,%20INC%2E
Select by county containing facilities of interest /restaurants/county/{county} eg: https://a4fpsm6md0.execute-api.us-east-1.amazonaws.com/api/restaurants/county/ONEIDA

Published at: https://app.swaggerhub.com/apis/9902350canada/restaurants/1.0
Swagger was not used to create the API, but nevertheless the API has been published as an FYI at swaggerhub.com from swagger/chalice-gis-demo-api-swagger.yaml which was exported from AWS API Gateway.
You can ignore the semantic error messages at swaggerhub.com and successfully run tests against the API.

Clone the Git repository: git clone https://github.com/mikequentel/chalice-gis-demo.git
Enable the Virtual Environment (via virtualenv): pip install -r requirements.txt
Install a local copy of the database businesses which contains the table restaurants by using the plain text dump data/businesses_backup.sql--example: assuming database named businesses already exists (that is, you already created the database), then for user postgres, run the command: psql -U postgres -h localhost --set ON_ERROR_STOP=on businesses < businesses_backup.sql
Set the appropriate credentials, which set environment variables used to connect to the database, in the file .chalice/config.json
Start the server locally by running chalice local which will deploy the server to http://localhost:8000
Now, you can run queries against the server through any HTTP client, but most easily through using the example at client/map.html

Account at Amazon Web Services
- Strongly advise that you create an IAM admin account and use it for day-to-day administrative tasks instead of the root account (root account is typically used for initial set up and billing/account settings).
Private keys (typically installed at ~/.aws) -- see the following for how to set up this:
- https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-welcome.html
- http://chalice.readthedocs.io/en/latest/quickstart.html

Create an AWS RDS database and load it with a PostgreSQL dump (such as the SQL file at data/businesses_backup.sql).
Modify the credentials for Chalice at .chalice/config.json
Deploy the demo using the command chalice deploy
Create a VPC to enable a connection between the resulting AWS Lambda and the RDS. Only need to set this up once. The RDS can be publically accessible but needs the VPC for proper performance; otherwise, the Lambda functions will time-out when attempting to call them through AWS API Gateway. If you are having configuration issues with the VPC and RDS, please see Troubleshoot Issues Connecting to an RDS Instance
The example client can also be deployed to AWS. I recommend using AWS S3 bucket to host a static web page (eg: client/map.html), and be sure to CORS-enable the bucket.