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Inventory Management System

This is a serverless inventory management system created with AWS services. NOTE: The system is temporarily unavailable to save costs on cloud resources usage. Please contact me if you wish to see the system in production.

Environment setup

Requirements

You need these on your computer before you can proceed with the setup.

• pip
• git
• Python >= 3.8
• aws-cdk

To Run locally

1. Clone this repository

$ git clone https://github.com/SarahTeoh/inventory-management-system.git 

2. Ensure CDK is installed

$ npm install -g aws-cdk

3. Create a python virtual environment:

$ python3 -m venv .venv

4. Activate the virtual environmetn On MacOS or Linux

$ source .venv/bin/activate

On Windows

% .venv\Scripts\activate.bat

5. Install required dependencies

$ pip install -r requirements.txt

6. Synthesize (cdk synth) or deploy (cdk deploy) the template

$ cdk synth
$ cdk deploy

To Test locally

$ python3 -m pytest 

API endpoints

(Temporarily unavailable)Base path: https://fs2hjjfa0d.execute-api.ap-southeast-1.amazonaws.com

	Http Method	Integrated Lambda	Function	Example Parameters
/inventory	POST	upsertInventoryFunction	Upsert item. If item with same name and same category doesn't exist, new item is created. If an item with same name and category exists, the item will be updated with new price.	{ "name": "Thing", "category": "Stationary", "price": 7.6 }
/inventories/filterByDateRange	GET	filterInventoryByDateRangeFunction	Filter items that have last_updated_dt within the date range and return total price of the items.	{ "dt_from": "2022-01-01 10:00:00", "dt_to": "2022-01-25 10:00:00" }
/inventories/aggregate	GET	aggregateInventoryFunction	Filter items by category and total price. If all is passed, it will return all category.	{ "category": "all" }
/inventories	POST	queryInventoryFunction	Query items with filters, pagination and sorting options.	{ "filters": { "name": "note" "category": "Stationary", "price_range": [1,10] }, "pagination": { "page": 1, "limit": 10 }, "sort": { "field": "price", "order": "asc" } }

Architecture

the cloud infrastructure resources are defined and provisioned using AWS Cloud Development Kit (CDK). This is the architecture used. AWS Services used and their functions are listed below.

Amazon Service	Function
API Gateway	Receive requests and return response
S3	Host frontend created with React
CloudFront	Fast content delivery network, acts as distributed cache of frontend hosted in S3 bucket
Lambda	Process requests
DynamoDB	Store data

Data model

The DynamoDB data model looks like this. The detailed diagram can be accessed under docs directory here.

	Type	Partition Key	Sort Key
Inventory Table	Base Table	name	category
CategoryPriceIndex	Global Secondary Index	category	price
ItemsLastUpdatedDtIndex	Global Secondary Index	static_pk	last_updated_dt
ItemsPriceIndex	Global Secondary Index	static_pk	price

Please note that the static_pk value is a constant "PRODUCT". This is because DynamoDB is schemaless, so in order to retrieve a record we need to provide the partition key(exact match). We will have to scan the dynamodb table if we don't have a partition key. This might consume a big amount of Read Capacity Unit(RCU). So I made up a constant value here as partition key to save cost. This is to save cost, but if the amount of data is big, we shall plan to use other design methods like partition sharding instead.