Downloading data from WIS2


This section provides guidance how to download data from WIS2 Global Services.

WIS2 Global Services include a Global Broker that provides users the ability to subscribe to data (via topics) and download to their local environment / workstation / decision support system from the WIS2 Global Cache.

The pywis-pubsub tool

wis2box enables subscribe and data download workflow the WIS2 network, by using the wis2box-subscribe-download container, inside of which runs the pywis-pubsub tool

pywis-pubsub is a Python package that provides publish, subscription and download capability of data from WIS2 Global Services.

Before starting the wis2box-subscribe-download container, the default configuration (provided in wis2box-subscribe-download/local.yml) must be updated, by defining the URL of the MQTT broker as well as the desired topic(s) to subscribe to.

In addition, the storage path should be updated to specify where downloaded data should be saved to.

# fully qualified URL of broker
broker: mqtts://username:password@host:port

# whether to run checksum verification when downloading data (default true)
verify_data: true

# whether to validate broker messages (default true)
validate_message: true

# list of 1..n topics to subscribe to
    - 'cache/a/wis2/topic1/#'
    - 'cache/a/wis2/topic2/#'

# storage: filesystem
    type: fs
        path: /tmp/foo/bar

To start a continuous subscribe and download process, run the wis2box-subscribe-download container as follows (-d for detached mode, --build to ensure changes in local.yml are built into the container):

docker compose -f docker.subscribe-download.yml up -d --build

To stop the subscribe and download process, run the following command:

docker compose -f docker.subscribe-download.yml down

Running pywis-pubsub interactively

pywis-pubsub can also be run interactively from inside the wis2box main container as follows:

# login to wis2box main container
python3 login

# edit a local configuration by using wis2box-subscribe-download/local.yml as a template
vi /data/wis2box/local.yml

# connect, and simply display data notifications
pywis-pubsub subscribe --config local.yml

# connect, and additionally download messages
pywis-pubsub subscribe --config local.yml --download

# connect, and filter messages by bounding box geometry
pywis-pubsub subscribe --config local.yml --bbox=-142,42,-52,84