Survey Service

This repository contains the Survey service. This microservice is a RESTful web service implemented using Go. This service features structured JSON logging, a self-bootstrapping database schema and database connection code that retries the connection if it's not available, increasing the time between each attempt. This eliminates the need to deploy services in a specific order.

Prerequisites

• Install the Godep package manager using go get github.com/tools/godep
• Run godep get to download and install the other dependencies managed by Godep

API

See API.md for API documentation.

Building

Install Go and ensure your GOPATH environment variable is set (usually it's ~/go).

Make

A Makefile is provided for compiling the code:

make

The compiled executable is placed within the build directory tree.

Docker Image

To build the Docker image, first compile the code using make then from the project root run:

make docker

Running

First compile the code using make then execute the binary in the background using ./surveysvc & from within the bin directory within the build directory tree.

The following environment variables may be overridden:

Environment Variable	Purpose	Default Value
DATABASE_URL	PostgreSQL postgres user connection string	postgres://postgres:password@localhost/postgres?sslmode=disable
PORT	HTTP listener port	:8080
security_user_name	HTTP basic authentication user name	N/A
security_user_password	HTTP basic authentication password	N/A
CONN_MAX_LIFETIME	Max lifetime of connection in pool in seconds	0, so there is no time limit
MAX_IDLE_CONN	Max idle connections to have in pool	2

Running locally with go run

It's possible to run the application locally using just go run main.go but in order to do so there are a few things to change:

• Update the dataSource database url in main.go to a valid postgres instance
• Update the migrationSource variable in main.go to file://./db-migrations

Once the app is running you should call the app with blank http auth values. This is because it's looking for the security_user_name and security_user_password environment variables. If they're not set, they just default to nothing.

Docker Image and PostgreSQL

To start Docker containers for both PostgreSQL and the Survey service, run:

docker compose up -d

To stop and remove the two Docker containers, run:

docker compose down

Testing

Run the unit tests using:

make test

To run the integration tests using make run:

make integration-test

This will build a docker image from source and run the container then run all tests including integration tests.

Cleaning

To clobber the build directory tree that's created when running make, run:

make clean

Database Migrations in Kubernetes

Due to limitations on the DB migration library in use in this project the following steps need to be followed to ensure a database migration is successful on a Kubernetes environment.

1. deploy the application via Spinnaker
2. scale the replicas to 1 pod (so it does the migration)
3. scale the replicas to 0 pods (to release the lock)
4. scale the replicas back to 2 pods again (or redeploy via Spinnaker)

Copyright

Copyright (C) 2017 - 2020 Crown Copyright (Office for National Statistics)