pombredanne / backdrop

Storing and querying data for the Performance Platform

Backdrop

##What is it?

Backdrop is a datastore built with Python and MongoDB. It is made up of two separately deployable APIs for reading and writing data over HTTP. The plan is to be able to gather data from a variety of sources and then aggregate and compare this data in useful ways.

• Data is grouped into data sets.
• Data is stored by posting JSON to the write API.
• Certain types of data are identified by reserved keys eg events are objects containing a timestamp.
• Reserved keys start with an underscore eg { "_timestamp": "2013-01-01T00:00:00Z }"
• Data is retrieved using HTTP GET requests against the read API.
• Data can be manipulated in a few useful ways with HTTP query strings eg /$DATA_GROUP/$DATA_TYPE?period=month for monthly grouped data.
• Backdrop is in constant development, so the best place to find examples and features are the feature tests

Getting set up

This assumes you are using the Performance Platform development environment and so have Python and MongoDB installed.

1. Check that you have virtualenv installed, if not sudo apt-get install python-virtualenv.
2. If you don't have virtualenvwrapper installed, create a virtualenv using virtualenv venv and source venv/bin/activate to enable it.
3. Navigate to the top level backdrop directory and run ./run_tests.sh. This will create a new virtualenv (if virtualenvwraper is installed), install all dependencies and run the tests.
4. source venv/bin/activate to enable the virtualenv if you didn't do this in step 2.
5. Copy backdrop/write/config/development_environment_sample.py to development_environment.py (if you want to) and edit as needed.

Starting the app

1. ./run_development.sh will start backdrop read and write on ports 3038 and 3039 respectively
2. Confirm you're up and running by requesting http://www.development.performance.service.gov.uk/_status

To start just the read or write applications:

1. ./start-app.sh takes two arguments: app (read or write) and port
2. ./start-app.sh read 3038 and/or ./start-app.sh write 3039

Testing

Run tests with ./run_tests.sh

Splinter tests are not run in Travis or Jenkins due to their instability.

Getting set up locally to test signon

Sign-on-o-Tron is a GOV.UK Ruby project that runs on a separate infrastructure to the Performance Platform.

Set up Sign-on-o-tron so that it can be accessed from signon.dev.gov.uk on your machine. It's easiest to do this using the GOV.UK development machine.

Add a new application: bundle exec rake applications:create name=backdrop redirect_uri=http://admin.development.performance.service.gov.uk/authorized

Edit /backdrop/admin/config/development_environment.py to contain your OAuth token and secret from the previous step.

Create a new user by following the prompts: bundle exec rake users:create name=Test [email protected] applications=backdrop

Visit http://admin.development.performance.service.gov.uk/

Requesting data

Requests return a JSON object containing a data array.

GET /data/$DATA_GROUP/$DATA_TYPE will return an array of data. Each element is an object.

GET /data/$DATA_GROUP/$DATA_TYPE?collect=score&group_by=name will return an array. In this case, each element of the array is an object containing a name value, a score array with the scores for that name and a _count value with the number of scores.

GET /data/$DATA_GROUP/$DATA_TYPE?filter_by=name:Foo returns all elements with name equal to "Foo".

GET /data/$DATA_GROUP/$DATA_TYPE?filter_by_prefix=name:Foo returns all elements with name beginning with "Foo".

Other parameters:

• start_at (YYYY-MM-DDTHH:MM:SS+HH:MM) and end_at (YYYY-MM-DDTHH:MM:SS+HH:MM)
• period ("week", "month")
• sort_by (FIELD:ascending)
• limit (integer)

Useful tools

• Copy data from an environment to the local Backdrop database (should be run on your host machine): cd tools && ./replicate-db.sh <youruser>@mongo-1.pp-preview

Emptying a dataset

To empty a dataset, get its token from stagecraft. Then run the following curl command

curl -X PUT -d "[]" https://{backdrop_url}/data/<data-group>/<data-type> -H 'Authorization: Bearer <token-from-stagecraft>' -H 'Content-Type: application/json'