Subscribers

A subscriber function reads data from tables in the Tabsdata server and writes the data to an external system.

Subscribers in Action

Tabsdata server

collection · warehouse

Table

vendors

//sales

Committed

Table

items

//sales

Committed

Connection

conn-mysql-dest.yaml

Subscriber

write_sales

Database

MySQL

MySQL · external

Not yet synced

Subscriber Code Anatomy

sales-sub.py

1from tabsdatak.api import subscriber, TableFrameSpec
2import tabsdatak.api.tableframe as tdf
3from tabsdatak.conn.mysql import MySQLDest
4 
5 
1@subscriber(
2    destination=MySQLDest(
8        tables=["vendors", "items"],
9        if_table_exists="replace",
10    ),
3    input_tables=["sales/vendors", "sales/items"],
12)
45def write_sales(vendors: TableFrameSpec, items: TableFrameSpec):
6    vendors = vendors.filter(tdf.col("active") == 1)
7    return (vendors, items)

• Declares the tables to read and where to write them.

  • Connector class that performs the write. Address and credentials come from the collection's connection.

  • Tables to ship out, as collection/table, mapped positionally to function body arguments.

• Plain Python over TableFrames. Usually short, since the connector does the writing.

  • One parameter per input table, in order.

  • Shapes the frames before they are written out.

  • One frame per destination table, in order. None skips that write.

For step-by-step guides on building a subscriber for a specific external system, see Subscribers under How-to Guides.