VOLTTRON base tagging library that provide common tagging api for users to associate haystack based tags and values to topic names and topic name prefixes. Implementing agents can persist tags in specific data store.

Tags used by this library have to be pre-defined in a resource file at volttron_data/tagging_resources. The library validates against this predefined list of tags every time user add tags to topics. Tags can be added to one topic at a time or multiple topics by using a topic name pattern(regular expression). This library uses tags from project haystack and adds a few custom tags for campus and VOLTTRON point name.

Each tag has an associated value and users can query for topic names based tags and its values using a simplified sql-like query string. Queries can specify tag names with values or tags without values for boolean tags(markers). Queries can combine multiple conditions with keyword AND, and OR, and use the keyword NOT to negate a conditions.

Requirements

• Python >= 3.10

Installation

This library can be installed using pip install volttron-lib-tagging. However, this is not necessary. Any implementing tagging agent that uses this library will automatically install it as part of its installation. For example, installing SQLiteTaggingAgent will automatically install volttron-lib-tagging into the same python environment

Dependencies and Limitations

1. When adding tags to topics this library calls the platform.historian's (or a configured historian's) get_topic_list and hence requires a platform.historian or configured historian to be running, but it doesn't require the historian to use sqlite3 or any specific database. It requires historian to be running only for using this api (add_tags) and does not require historian to be running for any other api.
2. Resource files that provides the list of valid tags is mandatory and should be in data_model/tags.csv
3. Tagging library only provides APIs to query for topic names based on tags. Once the list of topic names is retrieved, users should use the historian APIs to get the data corresponding to those topics.
4. Current version of tagging library does not support versioning of tag/values. When tags values are set it will overwrite any existing tag entries in the database

Development

Please see the following for contributing guidelines contributing.

Please see the following helpful guide about developing modular VOLTTRON agents

Disclaimer Notice

This material was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the United States Department of Energy, nor Battelle, nor any of their employees, nor any jurisdiction or organization that has cooperated in the development of these materials, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product, software, or process disclosed, or represents that its use would not infringe privately owned rights.

Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.