More documentation on godoc.
pgchangestream is a library used to stream changes off of a postgres database using logical decoding. The basic API is that you provide a connection string and replication slot name, and you get change messages sent along a channel. This can be useful for any sort of data streaming, such as responding to changes, loading data into a data warehouse, and more.
It is recommended that you familiarize yourself with the ideas around logical decoding before using this library to avoid sadness. For example, if you create a replicaiton slot and don't consume from it, your database will slowly use more and more disk space.
In order to use this library, you first need to ensure that an appropriate logical decoding plugin is installed on your postgres instance. Postgres comes with test_decoding, although wal2json is easier to use.
Once that's set up, you can create a replication slot using
select pg_create_logical_replication_slot('my_slot', 'wal2json');
my_slot is the name you will pass in as slotName when creating a reader.
The test cases require postgres to be installed and on your PATH. They can be run using go test.