Operators allow for generation of certain types of tasks that become nodes in
the DAG when instantiated. All operators derive from
inherit many attributes and methods that way.
There are 3 main types of operators:
Operators that performs an action, or tell another system to perform an action
Transfer operators move data from one system to another
Sensors are a certain type of operator that will keep running until a certain criterion is met. Examples include a specific file landing in HDFS or S3, a partition appearing in Hive, or a specific time of the day. Sensors are derived from
BaseSensorOperatorand run a poke method at a specified
poke_intervaluntil it returns
All operators are derived from
BaseOperator and acquire much
functionality through inheritance. Since this is the core of the engine,
it’s worth taking the time to understand the parameters of
to understand the primitive features that can be leveraged in your
Hooks are interfaces to external platforms and databases, implementing a common
interface when possible and acting as building blocks for operators. All hooks
are derived from
Executors are the mechanism by which task instances get run. All executors are
Models are built on top of the SQLAlchemy ORM Base class, and instances are persisted in the database.
Core and community package¶
Formerly the core code was maintained by the original creators - Airbnb. The code that was in the contrib package was supported by the community. The project was passed to the Apache community and currently the entire code is maintained by the community, so now the division has no justification, and it is only due to historical reasons. Currently, all new classes are added only to the contrib package.