+1 (binding) On Wed, Jun 17, 2020 at 3:39 AM 蒋晓峰 <thanosxnicho...@gmail.com> wrote:
> +1(not binding) > > On Wed, Jun 17, 2020 at 3:03 AM Gerard Casas Saez > <gcasass...@twitter.com.invalid> wrote: > > > Hi everyone, > > > > Sending an email here to consolidate an update to the AIP-31 that has > > happened while we have been implementing this. > > > > When AIP-31 was proposed, the proposal mentioned that all operators would > > have a __call__ method which would be used to define DAG in a functional > > manner. While implementing this with the SIG Functional Ops team, we > > decided to change that requirement and replace it with a better > integration > > with templated_fields and a new property in BaseOperator called output. > The > > idea is that (see AIP DAG example for variable reference) get_ip() == > > get_ip.output. > > > > I updated the AIP-31 doc to reflect those changes. Also took the chance > to > > clean the doc a bit to reword some smaller stuff, in order to make it > > easier for consumption by people outside of this group in the future. > > Update diff: > > > https://cwiki.apache.org/confluence/pages/diffpagesbyversion.action?pageId=148638736&selectedPageVersions=12&selectedPageVersions=11 > > Updated AIP-31: > > > https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=148638736 > > > > Regarding the output property change, you can follow this discussion in > > the current Airflow PR between me and Ash, to understand better the > > motivations behind it: > > https://github.com/apache/airflow/pull/8962/files#r441004317. > > > > A short summary: > > The main reason for this change was that sometimes templated args > > in operators are required on initialization > > (example: subject on EmailOperator). This meant that you needed to add a > > placeholder value on initialization, and then specify the XComArg that > > needed to be used instead in the __call__ method. This seemed a bit > > confusing, so when implementing we decided to rollback > > the __call__ addition to BaseOperator. > > > > This made it difficult to get XComArg from an operator as the > > initializer returns an instance of the operator instead of > > an XComArg compared to the proposed __call__ method. For that, we > proposed > > to add a new property output to BaseOperator that would generate an > XComArg > > for the operator with return_value as the default key. > > > > An example of how different the DAG looks between the previous AIP and > the > > new update can be found here: > > https://github.com/apache/airflow/pull/8962/files#r441013469 > > > > With that said, I will follow Ash recommendation and try to get a lazy > > consensus on this change: > > Allow 48h for committers and developers to comment/bring up > > objections on the change. > > > > If no objection is raised by Thursday June 18th at 1PM MST, we will move > > forward with the change and merge > > https://github.com/apache/airflow/pull/8962 PR. > > > > Thanks everyone for all the work on this change! 🎉 > > > > Gerard Casas Saez > > Twitter | Cortex | @casassaez > > >
