Why do we need airflow hooks?

Question

Doc says:

Hooks are interfaces to external platforms and databases like Hive, S3, MySQL, Postgres, HDFS, and Pig. Hooks implement a common interface when possible, and act as a building block for operators. Ref

But why do we need them?

I want to select data from one Postgres DB, and store to another one. Can I use, for example, psycopg2 driver inside python script, which runs by a python operator, or airflow should know for some reason what exactly I'm doing inside script, so, I need to use PostgresHook instead of just psycopg2 driver?

Answer 1

You should use just PostresHook. Instead of using psycopg2 as so:

conn = f'{pass}:{server}@host etc}'
cur = conn.cursor()
cur.execute(query)
data = cur.fetchall()

You can just type:

postgres = PostgresHook('connection_id')
data = postgres.get_pandas_df(query)

Which can also make use of encryption of connections.

So using hooks is cleaner, safer and easier.