Copy Activity Fabric

use dataflow/notebook after the copy activity to extract metrics from the output JSON. I have copied some example (from web, hope this will show you the path) in a notebook using Pipeline().activity() output, this stores the rowsRead and rowsCopied values into your Fabric warehouse log table.

import json
from notebookutils import mssparkutils

# Get Copy activity output
output = mssparkutils.pipeline.getOutput("CopyActivityName")
data = json.loads(output)

rows_read = data["rowsRead"]
rows_copied = data["rowsCopied"]

# Write to fabric warehouse tbl
spark.sql(f"""
INSERT INTO log_table (activity_name, rows_read, rows_copied, load_time)
VALUES ('CopyActivityName', {rows_read}, {rows_copied}, CURRENT_TIMESTAMP)
""")

Make sure to customize/modify to suit your req.