DWP Assessment Go

An API which calls the API at https://dwp-techtest.herokuapp.com, and returns people who are listed as either living in London, or whose current coordinates are within 50 miles of London.

Contents

• Getting Started
• API Endpoints
• OpenAPI Specification
• Configuration
• Testing
• Conventional Commits
• GitHub Actions

Getting Started

Prerequisites

To install, run and modify this project you will need to have:

• Go
• Git
• Docker

Installation

To start, please fork and clone the repository to your local machine. You are able to run the service directly on the command line, using Docker, or with your IDE of choice.

Running

Command Line

To run the service from the command line first execute the following command:

go run cmd/web/*

Docker

The included Dockerfile allows the service to be containerised and run using Docker. You can build an image and then start a container from it, exposing the internal port of 8080.

docker build --build-arg BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ') -t j-r-oliver/dwp-assessment-go .
docker run --name dwp-assessment-go -p 8080:8080 j-r-oliver/dwp-assessment-go

Docker Compose

A Docker Compose file has been provided to facilitate running the service in conjunction with a WireMock of the upstream DWP API. This WireMock provides a local instance of the DWP API allowing for development regardless of external connectivity.

To start the service and the WireMock you will need to execute Docker Compose up dwp-assessment-go. This will start both services simultaneously and set the PEOPLE_ENDPOINT environment variable to the local WireMock instance.

docker-compose up dwp-assessment-go

By passing the name of the service defined in the docker-compose.yml file you may start the services individually. By default the PEOPLE_ENDPOINT environment variable will be set to the local WireMock instance when starting from _ Docker Compose_. This can be overridden to the hosted Heroku API by passing in the PEOPLE_ENDPOINT environment variable as demonstrated below.

docker-compose up wiremock

PEOPLE_ENDPOINT=https://dwp-techtest.herokuapp.com docker-compose up dwp-assessment-go

API Endpoints

There are two RESTful API endpoints available:

/api/people

Returns all people available from the DWP API.

/api/people/{city}

Returns all people who are listed as either living in the city or whose current coordinates are within 50 miles of the coordinates of the city. Currently, only london has been configured as an available city. All other requests will result in a 404 - City Not Found response. For example /api/people/london will return all people living in London or whose coordinates are within 50 miles of London.

An optional query has also been configured for the {city} endpoint to amend the default distance. For example, the path and query below would return all people living in London or whose coordinates are within 25 miles of London

/api/people/london?distance=25

OpenAPI Specification

An OpenAPI Specification has been provided and can be found in ./openapi-specification. The specification hasn't been used for code generation due the desire to explore Go's capabilities.

Configuration

Service configuration is managed using environment variables and the configuration.yaml. This allows the service to be aware of necessary configuration and to provide sensible defaults. City coordinates can be configured by adding to the cities key.

cities:
  London:
    lat: 51.514248
    lon: -0.093145
  manchester:
    lat: 53.480759
    lon: -2.242630

Environment Variables

The following environment variables are available for configuration:

Environment Variable	Default	Description
PORT	8080	Port number for the service
LOGGING_LEVEL	info	Sets the logging level to be outputted to the logs (error, info or debug)
PEOPLE_ENDPOINT	https://dwp-techtest.herokuapp.com	People / Users API endpoint
$PEOPLE_DISTANCE	50	Default distance in miles from city's coordinates

Testing

All tests have been written using the testing package from the Standard library.

Unit Tests

To run the unit tests execute:

go test -v ./...

Code coverage is also measured by using the testing package. To run tests with coverage execute:

go test -coverprofile=coverage.out  ./...

Component Tests

Component tests has been written that exercise the service against the WireMock. The easiest way to execute the tests is to use docker-compose. The following command will start the WireMock, then the service under tests, and then execute the tests.

docker-compose up --renew-anon-volumes --exit-code-from api-tests

To run the tests locally, without Docker, execute the following command:

go test -v -tags=component ./api-tests

The URL of the service inside the tests can be configured using the BASE_URL environment variable. A default of http://localhost:8080has been configured.

Conventional Commits

This project uses the Conventional Commits specification for commit messages. The specification provides a simple rule set for creating commit messages, documenting features, fixes, and breaking changes in commit messages.

A pre-commit configuration file has been provided to automate commit linting. Ensure that pre-commit has been installed and execute...

pre-commit install

...to add a commit Git hook to your local machine.

An automated pipeline job has been configured to lint commit messages on a push.

GitHub Actions

A CI/CD pipeline has been created using GitHub Actions to automated tasks such as linting and testing.

Build Workflow

The build workflow handles integration tasks. This workflow consists of three jobs, Gitand Go, that run in parallel, and then Docker, if Git and Go are successful. This workflow is triggered on a push to a branch.

Git

This job automates tasks relating to repository linting and enforcing best practices.

Go

This job automates Go specific tasks.

Docker

This job automates Docker specific tasks and the component tests.