Trade Tariff Backend

Now maintainded by HMRC

The API back-end for:

• Trade Tariff Frontend
• Trade Tariff Admin

Other related projects:

• Trade Tariff Oracle

Development

Dependencies

• Ruby
• Postgresql
• ElasticSearch
• Redis

Setup

Please go through this updated setup document

1. Setup your environment.

   bin/setup

2. Update .env file with valid data.

3. Start Foreman.

   foreman start

4. Verify that the app is up and running.

   open http://localhost:3018/healthcheck

Load database

Check out wiki article on the subject, or get a recent database snapshot.

Performing daily updates

These are run hourly by a background worker UpdatesSynchronizerWorker.

Sync process

• checking failures (check tariff_synchronizer.rb) - if any of updates failed in the past, sync process will not proceed
• downloading missing files up to Date.today (check base_update.rb and download methods in taric_update.rb and chief_update.rb)
• applying downloaded files (applying measures, etc. TARIC first, then CHIEF)

Updates are performed in portions and protected by redis lock (see TariffSynchronizer#apply).

BaseUpdate#apply is responsible for most of the logging/checking job and running import! methods located in Taric/ChiefUpdate classes. Then it runs TaricImporter and ChiefImporter to parse and store xml/csv files.

Whole process is quite similar for both TARIC and CHIEF, but CHIEF updates undergo a tranformation transformation process to convert them into a TARIC format. Check ChiefTransformer class for more info (and ChiefUpdate#import!).

In case of any errors, changes (per single update) are roll-backed and record itself is marked as failed. The sync would need to be rerun after a rollback.

Deployment

We deploy to cloud foundry, so you need to have the CLI installed, and the following cf plugin installed:

Set the following ENV variables:

• CF_USER
• CF_PASSWORD
• CF_ORG
• CF_SPACE
• CF_APP
• CF_APP_WORKER
• HEALTHCHECK_URL
• SLACK_CHANNEL
• SLACK_WEBHOOK

Then run

./bin/deploy

NB: In the newer Diego architecture from CloudFoundry, no-route skips creating and binding a route for the app, but does not specify which type of health check to perform. If your app does not listen on a port, for example the sidekiq worker, then it does not satisfy the port-based health check and Cloud Foundry marks it as crashed. To prevent this, disable the port-based health check with cf set-health-check APP_NAME none.

Scaling the application

We are using CF AutoScaler plugin to perform application autoscaling. Set up guide and documentation are available by links below:

https://docs.cloud.service.gov.uk/managing_apps.html#autoscaling

https://github.com/cloudfoundry/app-autoscaler/blob/develop/docs/Readme.md

To check autoscaling history run:

cf autoscaling-history APPNAME

To check autoscaling metrics run:

cf autoscaling-metrics APP_NAME METRIC_NAME

To remove autoscaling policy and disable App Autoscaler run:

cf detach-autoscaling-policy APP_NAME

To create or update autoscaling policy for your application run:

cf attach-autoscaling-policy APP_NAME ./policy.json

Current autosscaling policy files are here.

Notes

• When writing validators in app/validators please run the rake task audit:verify which runs the validator against existing data.

Contributing

Please check out the Contributing guide

Licence

Trade Tariff is licenced under the MIT licence