fink-client

Fink client

fink-client is a light package to manipulate catalogs and alerts issued from the fink broker programmatically. It is used in the context of 2 major Fink services: Livestream and Data Transfer.

Installation

fink_client requires a version of Python 3.9+.

Install with pip

pip install fink-client --upgrade

Use or develop in a controlled environment

For development, we recommend the use of a virtual environment:

git clone https://github.com/astrolabsoftware/fink-client.git
cd fink-client
python -m venv .fc_env
source .fc_env/bin/activate
pip install -r requirements.txt
pip install .

Registration

In order to connect and poll alerts from Fink, you need to get your credentials:

1. Subscribe to one or more Fink streams by filling this form.
2. After filling the form, we will send your credentials. Register them on your laptop by simply running:

fink_client_register -username <USERNAME> -group_id <GROUP_ID> ...

Livestream usage

Once you have your credentials, you are ready to poll streams! You can easily access the documentation using -h or --help:

fink_consumer -h
usage: fink_consumer [-h] [--display] [--display_statistics] [-limit LIMIT]
                     [--available_topics] [--save] [-outdir OUTDIR]
                     [-schema SCHEMA] [--dump_schema] [-start_at START_AT]

Kafka consumer to listen and archive Fink streams from the Livestream service

optional arguments:
  -h, --help            show this help message and exit
  --display             If specified, print on screen information about
                        incoming alert.
  --display_statistics  If specified, print on screen information about queues,
                        and exit.
  -limit LIMIT          If specified, download only `limit` alerts. Default is
                        None.
  --available_topics    If specified, print on screen information about
                        available topics.
  --save                If specified, save alert data on disk (Avro). See also
                        -outdir.
  -outdir OUTDIR        Folder to store incoming alerts if --save is set. It
                        must exist.
  -schema SCHEMA        Avro schema to decode the incoming alerts. Default is
                        None (version taken from each alert)
  --dump_schema         If specified, save the schema on disk (json file)
  -start_at START_AT    If specified, reset offsets to 0 (`earliest`) or empty
                        queue (`latest`).

You can also look at an alert on the disk:

fink_alert_viewer -h
usage: fink_alert_viewer [-h] [-filename FILENAME]

Display cutouts and lightcurve from a ZTF alert

optional arguments:
  -h, --help          show this help message and exit
  -filename FILENAME  Path to an alert data file (avro format)

More information at docs/livestream.

Data Transfer usage

If you requested data using the Data Transfer service, you can easily poll your stream using:

usage: fink_datatransfer.py [-h] [-topic TOPIC] [-limit LIMIT] [-outdir OUTDIR] [-partitionby PARTITIONBY] [-batchsize BATCHSIZE] [-nconsumers NCONSUMERS]
                            [-maxtimeout MAXTIMEOUT] [-number_partitions NUMBER_PARTITIONS] [--restart_from_beginning] [--verbose]

Kafka consumer to listen and archive Fink streams from the data transfer service

optional arguments:
  -h, --help            show this help message and exit
  -topic TOPIC          Topic name for the stream that contains the data.
  -limit LIMIT          If specified, download only `limit` alerts from the stream. Default is None, that is download all alerts.
  -outdir OUTDIR        Folder to store incoming alerts. It will be created if it does not exist.
  -partitionby PARTITIONBY
                        Partition data by `time` (year=YYYY/month=MM/day=DD), or `finkclass` (finkclass=CLASS), or `tnsclass` (tnsclass=CLASS). `classId` is
                        also available for ELASTiCC data. Default is time.
  -batchsize BATCHSIZE  Maximum number of alert within the `maxtimeout` (see conf). Default is 1000 alerts.
  -nconsumers NCONSUMERS
                        Number of parallel consumer to use. Default (-1) is the number of logical CPUs in the system.
  -maxtimeout MAXTIMEOUT
                        Overwrite the default timeout (in seconds) from user configuration. Default is None.
  -number_partitions NUMBER_PARTITIONS
                        Number of partitions for the topic in the distant Kafka cluster. Do not touch unless you know what your are doing. Default is 10
                        (Fink Kafka cluster)
  --restart_from_beginning
                        If specified, restart downloading from the 1st alert in the stream. Default is False.
  --verbose             If specified, print on screen information about the consuming.

More information at docs/datatransfer.