PCQ Backend Application

This is the frontend for the protected characteristics questionnaire service. This service will ask a set of questions that will help us check we are treating people fairly and equally. It helps us to meet our commitment to equality (under the Equality Act 2010).

Overview

pcq-frontend • pcq-backend • pcq-consolidation-service • pcq-shared-infrastructure • pcq-loader

Purpose

This is the Protected Characteristics Back-End application that will save user's answers to the database, fetch PCQ Ids that don't have an associated case record and add case information to a PCQ record in the database. The API will be invoked by two components - PCQ front-end and the Consolidation service

What's inside

The application exposes health endpoint (http://localhost:4550/health).

Plugins

The application uses the following plugins:

• checkstyle https://docs.gradle.org/current/userguide/checkstyle_plugin.html
• pmd https://docs.gradle.org/current/userguide/pmd_plugin.html
• jacoco https://docs.gradle.org/current/userguide/jacoco_plugin.html
• io.spring.dependency-management https://github.com/spring-gradle-plugins/dependency-management-plugin
• org.springframework.boot http://projects.spring.io/spring-boot/
• org.owasp.dependencycheck https://jeremylong.github.io/DependencyCheck/dependency-check-gradle/index.html
• com.github.ben-manes.versions https://github.com/ben-manes/gradle-versions-plugin

Building and deploying the application

Building the application

The project uses Gradle as a build tool. It already contains ./gradlew wrapper script, so there's no need to install gradle.

To build the project execute the following command:

  ./gradlew build

Running the application

To run the PostgreSQL 11 PCQ database, execute docker-compose to build the database from the postgreSQL docker image:

  docker-compose -f docker-compose.yml up pcq-database

To run the PCQ Backend application, execute the gradle run command - this also adds the PCQ schema to the database.

  ./gradlew run

Finally to use the pcq-backend application, you'll need to add the encryption package to PostgreSQL. Using your favourite SQL client run the following from the PCQ database. See .env file for dev database password.

 psql -h 0.0.0.0 -p 5050 -d pcq -u pcquser
 CREATE EXTENSION IF NOT EXISTS pgcrypto;

Environment variables

The .env file has a list of the environment variables in use by the pcq-backend and pcq-database components. These are as follows:

• PCQ_DB_NAME
• PCQ_DB_HOST
• PCQ_DB_PORT
• PCQ_DB_USERNAME
• PCQ_DB_PASSWORD
• FLYWAY_URL
• FLYWAY_USER
• FLYWAY_PASSWORD
• FLYWAY_NOOP_STRATEGY
• JWT_SECRET
• DB_ENCRYPTION_KEY

There is no need to export these values if pcq-backend repo is checked out. If another service is using the pcq-backend application, the environment values are available through a batch script:

  source ./bin/set-pcq-docker-env.sh

Manually building the PCQ Database using Flyway

The pcq-backend application will automatically create the PCQ database definitions from the flyway scripts included in the build. However if you would like to add the table definitions manually you'll need to execute the gradle migrate script:

  ./gradlew -Pflyway.user=pcquser -Pflyway.password=pcqpass -Pflyway.url=jdbc:postgresql://0.0.0.0:5050/pcq flywayMigrate

Running the application in Docker

Build docker image

Create docker image:

  docker-compose build

Bring the database and pcq-backend application up in Docker. by executing the following command:

  docker-compose up

az login az acr login --name hmctspublic --subscription DCD-CNP-Prod

This will start the API container exposing the application's port (set to 4550 in this template app).

In order to test if the application is up, you can call its health endpoint:

  curl http://localhost:4550/health

You should get a response similar to this:

  {"status":"UP","diskSpace":{"status":"UP","total":249644974080,"free":137188298752,"threshold":10485760}}

Notes:

Accessing Azure Container Repository

Run the following to install the azure and kubernetes command-line tools

  brew install azure-cli
  az acs kubernetes install-cli

login to azure - you'll not need hmctsprivate access for PCQ.

  az login (will open a browser to login)
  az acr login --name hmctspublic --subscription DCD-CNP-Prod
  az acr login --name hmctsprivate --subscription DCD-CNP-Prod

Removing old docker images

Old containers can be removed by executing the following command:

  docker rm $(docker ps -a -q)

You may need to forcibly remove any relevant images by executing the following command:

  docker rmi $(docker images -q)

Finally you can remove all volumes - note this removes all existing database values:

  docker volume rm $(docker volume ls -q)

There is no need to remove postgres and java or similar core images.

Hystrix

Hystrix is a library that helps you control the interactions between your application and other services by adding latency tolerance and fault tolerance logic. It does this by isolating points of access between the services, stopping cascading failures across them, and providing fallback options. We recommend you to use Hystrix in your application if it calls any services.

Hystrix circuit breaker

This API has Hystrix Circuit Breaker already enabled. It monitors and manages all the@HystrixCommand or HystrixObservableCommand annotated methods inside @Component or @Service annotated classes.

Other

Hystrix offers much more than Circuit Breaker pattern implementation or command monitoring. Here are some other functionalities it provides:

• Separate, per-dependency thread pools
• Semaphores, which you can use to limit the number of concurrent calls to any given dependency
• Request caching, allowing different code paths to execute Hystrix Commands without worrying about duplicating work

License

This project is licensed under the MIT License - see the LICENSE file for details