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Re: Lineage


Hi Bolke,

Data lineage support sounds very interesting.

I'm not very familiar with Atlas but first sight seems like a tool specific
to the Hadoop ecosystem. How would this look like if the files (inlets or
outlets) were stored on s3?.

An example of a service that manages a similar use case is AWS Glue[1],
which creates a hive metastore based on the schema and other metadata it
can get from different sources (amongst them, s3 files).


On Sun, May 6, 2018 at 7:49 AM, Bolke de Bruin <bdbruin@xxxxxxxxx> wrote:

> Hi All,
>
> I have made a first implementation that allows tracking of lineage in
> Airflow and integration with Apache Atlas. It was inspired by Jeremiah’s
> work in the past on Data Flow pipelines, but I think I kept it a little bit
> simpler.
>
> Operators now have two new parameters called “inlets” and “outlets”. These
> can be filled with objects derived from “DataSet”, like “File” and
> “HadoopFile”. Parameters are jinja2 templated, which
> means they receive the context of the task when it is running and get
> rendered. So you can get definitions like this:
>
> f_final = File(name="/tmp/final")
> run_this_last = DummyOperator(task_id='run_this_last', dag=dag,
>     inlets={"auto": True},
>     outlets={"datasets": [f_final,]})
>
> f_in = File(name="/tmp/whole_directory/")
> outlets = []
> for file in FILE_CATEGORIES:
>     f_out = File(name="/tmp/{}/{{{{ execution_date }}}}".format(file))
>     outlets.append(f_out)
> run_this = BashOperator(
>     task_id='run_after_loop', bash_command='echo 1', dag=dag,
>     inlets={"auto": False, "task_ids": [], "datasets": [f_in,]},
>     outlets={"datasets": outlets}
>     )
> run_this.set_downstream(run_this_last)
>
> So I am trying to keep to boilerplate work down for developers. Operators
> can also extend inlets and outlets automatically. This will probably be a
> bit harder for the BashOperator without some special magic, but an update
> to the DruidOperator can be relatively quite straightforward.
>
> In the future Operators can take advantage of the inlet/outlet definitions
> as they are also made available as part of the context for templating (as
> “inlets” and “outlets”).
>
> I’m looking forward to your comments!
>
> https://github.com/apache/incubator-airflow/pull/3321
>
> Bolke.



[1] https://aws.amazon.com/glue/

Cheers,

-- 
Gerardo Curiel // https://gerar.do