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)

• Defines the input Tables and destination for the Subscriber.

  • Writes data to the external system. The Collection's Connection provides the address and credentials.

  • Tabsdata Tables to read. This Subscriber reads vendors and items from the sales Collection.

• Receives the input data and returns the data to write to MySQL.

  • The vendors and items arguments receive the data from input_tables in the order listed.

  • Filters the vendors to include only active vendors.

  • The returned data is written to the destination Tables in the order listed in tables. Returning None for a Table skips the write.

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