Business Register PAYE API

Supports retrieval of Paye As You Earn (PAYE) admin data.

See the Open API Specification for details of the API.

Development Tasks

Run the service in development mode (default Play port of 9000):

sbt run

Run the service in development mode (custom port of 9123):

sbt "run 9123"

Run unit tests with coverage:

sbt clean coverage test coverageReport

Run acceptance tests:

sbt it:test

Run all tests:

sbt clean test it:test

Generate static analysis report:

sbt scapegoat

Testing Against a Local HBase Database

Start HBase
```
bin/start-hbase.sh
```
Create Database Schema
```
bin/hbase shell
```
In the resulting HBase Shell, create the namespace:
```
create_namespace 'br_paye_db'
```
followed by the table:
```
create 'br_paye_db:paye', 'd', 'h'
```

Create Sample Data

Create one record with only mandatory fields:

put 'br_paye_db:paye', '054G6Y20621', 'd:payeref', '054G6Y20621-payeref'
put 'br_paye_db:paye', '054G6Y20621', 'd:nameline1', '054G6Y20621-nameline1'
put 'br_paye_db:paye', '054G6Y20621', 'd:legalstatus', '054G6Y20621-legalstatus'
put 'br_paye_db:paye', '054G6Y20621', 'd:address1', '054G6Y20621-address1'
put 'br_paye_db:paye', '054G6Y20621', 'd:postcode', '054G6Y20621-postcode'

And another with all possible fields:

put 'br_paye_db:paye', '076I8A42843', 'd:payeref', '076I8A42843-payeref'
put 'br_paye_db:paye', '076I8A42843', 'd:nameline1', '076I8A42843-nameline1'
put 'br_paye_db:paye', '076I8A42843', 'd:nameline2', '076I8A42843-nameline2'
put 'br_paye_db:paye', '076I8A42843', 'd:nameline3', '076I8A42843-nameline3'
put 'br_paye_db:paye', '076I8A42843', 'd:tradstyle1', '076I8A42843-tradstyle1'
put 'br_paye_db:paye', '076I8A42843', 'd:tradstyle2', '076I8A42843-tradstyle2'
put 'br_paye_db:paye', '076I8A42843', 'd:tradstyle3', '076I8A42843-tradstyle3'
put 'br_paye_db:paye', '076I8A42843', 'd:legalstatus', '076I8A42843-legalstatus'
put 'br_paye_db:paye', '076I8A42843', 'd:prevpaye', '076I8A42843-prevpaye'
put 'br_paye_db:paye', '076I8A42843', 'd:employer_cat', '076I8A42843-employer_cat'
put 'br_paye_db:paye', '076I8A42843', 'd:stc', '076I8A42843-stc'
put 'br_paye_db:paye', '076I8A42843', 'd:actiondate', '076I8A42843-actiondate'
put 'br_paye_db:paye', '076I8A42843', 'd:birthdate', '076I8A42843-birthdate'
put 'br_paye_db:paye', '076I8A42843', 'd:deathdate', '076I8A42843-deathdate'
put 'br_paye_db:paye', '076I8A42843', 'd:deathcode', '076I8A42843-deathcode'
put 'br_paye_db:paye', '076I8A42843', 'd:mar_jobs', '103'
put 'br_paye_db:paye', '076I8A42843', 'd:june_jobs', '106'
put 'br_paye_db:paye', '076I8A42843', 'd:sept_jobs', '109'
put 'br_paye_db:paye', '076I8A42843', 'd:dec_jobs', '112'
put 'br_paye_db:paye', '076I8A42843', 'd:jobs_lastupd', '076I8A42843-jobs_lastupd'
put 'br_paye_db:paye', '076I8A42843', 'd:mfullemp', '211'
put 'br_paye_db:paye', '076I8A42843', 'd:msubemp', '212'
put 'br_paye_db:paye', '076I8A42843', 'd:ffullemp', '221'
put 'br_paye_db:paye', '076I8A42843', 'd:fsubemp', '222'
put 'br_paye_db:paye', '076I8A42843', 'd:unclemp', '231'
put 'br_paye_db:paye', '076I8A42843', 'd:unclsubemp', '232'
put 'br_paye_db:paye', '076I8A42843', 'd:address1', '076I8A42843-address1'
put 'br_paye_db:paye', '076I8A42843', 'd:address2', '076I8A42843-address2'
put 'br_paye_db:paye', '076I8A42843', 'd:address3', '076I8A42843-address3'
put 'br_paye_db:paye', '076I8A42843', 'd:address4', '076I8A42843-address4'
put 'br_paye_db:paye', '076I8A42843', 'd:address5', '076I8A42843-address5'
put 'br_paye_db:paye', '076I8A42843', 'd:postcode', '076I8A42843-postcode'
put 'br_paye_db:paye', '076I8A42843', 'd:ubrn', '076I8A42843-ubrn'

Start HBase Rest Service
```
bin/hbase rest start
```

Start This Service

export BR_PAYE_QUERY_DB_HBASE_NAMESPACE=br_paye_db
export BR_PAYE_QUERY_DB_HBASE_TABLE_NAME=paye

sbt clean run

This runs the service on the default Play port (9000).

Query This API

curl -i http://localhost:9000/v1/paye/054G6Y20621
curl -i http://localhost:9000/v1/paye/076I8A42843

Clerically edit a unit (modifying the existing UBRN)

curl -i \
-H "Content-Type: application/json-patch+json" \
-H "X-User-Id: bloggsj" \
-d '[{"op": "test", "path": "/links/ubrn", "value": "076I8A42843-ubrn"},
     {"op": "replace", "path": "/links/ubrn", "value": "1234567890123456"}]' \
-X PATCH \
"http://localhost:9000/v1/paye/076I8A42843"

Shutdown This Service

Terminate the running command (typically Ctrl-C).

TearDown Database

Delete the table:

disable 'br_paye_db:paye'
drop 'br_paye_db:paye'

followed by the namespace:

drop_namespace 'br_paye_db'

Shutdown HBase REST Service

bin/hbase rest stop
Shutdown HBase
```
bin/hbase stop-hbase.sh
```

API Specification

The api.yaml file in the root project directory documents the API using the Open API Specification. This file is best edited using Swagger Editor and best viewed using Swagger UI. The Docker approach outlined here seems to work well.

Tracing

kamon is used to automatically instrument the application and report trace spans to zipkin. The AspectJ Weaver is required to make this happen, see adding-the-aspectj-weaver for further details.

Kamon takes care of propagating the traceId across threads, and making the relevant traceId available to logback's Mapped Diagnostic Context (MDC).

Tracing is not enabled during the execution of tests, resulting in log statements that contain a traceId with the value "undefined".

To undertake manual trace testing, run a local Zipkin 2 server. One simple way to do this is via Docker:

docker run --rm -d -p 9411:9411 openzipkin/zipkin:2.11

Then run this service via sbt run, and exercise an endpoint.

The resulting trace information should be available in the Zipkin UI at http://localhost:9411/zipkin/.

Service Configuration

As is standard for Play, the runtime configuration file can be found at src/main/resources/application.conf.

This file adopts a pattern where each variable has a sensible default for running the application locally, which may then be overridden by an environment variable (if defined). For example:

host = "localhost"
host = ${?BR_PAYE_QUERY_DB_HBASE_HOST}

The actual settings used for our formal deployment environments are held outside of Github, and rely on the the ability to override settings via environment variables in accordance with the '12-factor app' approach.

Note that acceptance tests (and the entire IntegrationTest phase generally) use a dedicated configuration that is defined at src/it/resources/it_application.conf. This imports the standard configuration, and then overrides the environment to that expected by locally executing acceptance tests. This allows us to specify non-standard ports for example, to avoid conflicts with locally running services. For this to work, the build file overrides the -Dconfig.resource setting when executing the IntegrationTest phase.

Edit History

A history of edits is maintained in a separate 'h' column family.

For each edit a new history cell is created. The column name of this cell is a UUID, and the cell value has the format:

{userId}~{iso-local-date-time}~{old-ubrn}~{new-ubrn}

For example:

column=h:90731d6b-d98f-450b-871d-806d13901953,
value=bloggsj~2019-01-23T09:22:39.264~1234567890123456~9999999999999999

Metadata for the edit (currently the editedBy userId) must be supplied by HTTP Headers (currently X-User-Id). Any PATCH request without the required metadata headers will receive a Bad Request (400) response.