kv-store

A key-value store exposed via a web server. A CLI client is also provided which consumes the web service.

Architecture

Usage

Installing

• Clone this repository.
• Install Rust.

CLI Operations

• get(key): cargo run --bin client -- get {key}, get the value of the key, if present.
• set(key, val): cargo run --bin client -- set {key} {val}, set the key-value pair
• rm(key): cargo run --bin client -- rm {key} remove the key, if present.
• sub: cargo run --bin client -- sub subscribe to any changes happening to any keys.

Server API

Run the server: cargo run --bin server

Route	Body	Response	Status
/set	{ "key": "abc", "val": "xyz" }	{ "inserted": true, "ejected_val": null }	201
/get?key=abc		{ "found": true, "inserted_val": "xyz" }	200
/rm	{ "key": "abc" }	{ "found": true, "removed": true, "ejected_val": "xyz" }	200

Docker

• Build the server image: docker build -t kv-store .
• Run the container: docker run -p 8000:8000 --env KVSTORE_SERVER_HOST=0.0.0.0:8000 kv-store To subscribe to changes happening to keys, we also need to run a NATS server, which serves the purpose of a message queue. There's a docker-compose.yml provided to make this easier.
• Populate the .env

KVSTORE_NATS_HOST=nats:4222
KVSTORE_SERVER_HOST=0.0.0.0:8000

• Run the services: docker-compose -f docker-comppose.dev.yml up --build

Tests

• To run tests: cargo test

Repo Structure

• src/store.rs: Contains the main buisness logic behing the get, set and rm operations.
• src/error.rs: Defines the custom error/result types.
• src/models.rs: Contains the various server request/response structures.
• src/pubsub.rs: Contains helper methods related to publishing and subscribing to NATS.
• src/bin/client.rs: Defines the CLI which consumes the web service and/or subscribes to changes to keys.
• src/bin/server.rs: Launches the server and publishes any changes happening to any keys.

CI/CD

• CI: Workflows run on GitHub Actions. cargo fmt and cargo clippy is used to ensure linting and code quality. All tests are run and code coverage is reported using tarpaulin and coveralls.

• CD: The production server is deployed on an EC2 instance(http://13.233.94.11) using docker-compose, which runs three services:

  • the kv-store server
  • a NATS server
  • a HAProxy load balancer

  A Jenkins server is also hosted on the same instance, which is used for deploying new changes. A push to the main branch will trigger a Jenkins job, which checks out the latest code, zips it and pushes it to a S3 bucket. An AWS CodeDeploy deployment is then triggered which runs deploy.sh, a shell script which performs rolling deployments.