TheNeuralBit commented on a change in pull request #13871: URL: https://github.com/apache/beam/pull/13871#discussion_r571129144
########## File path: website/www/site/content/en/documentation/basics.md ########## @@ -0,0 +1,193 @@ +--- +title: "Basics of the Beam model" +--- +<!-- +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + +http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +--> + +# Basics of the Beam model + +Suppose you have a data processing engine that can pretty easily process graphs +of operations. You want to integrate it with the Beam ecosystem to get access +to other languages, great event time processing, and a library of connectors. +You need to know the core vocabulary: + + * [_Pipeline_](#pipeline) - A pipeline is a graph of transformations that a user constructs + that defines the data processing they want to do. + * [_PCollection_](#pcollections) - Data being processed in a pipeline is part of a PCollection. + * [_PTransforms_](#ptransforms) - The operations executed within a pipeline. These are best + thought of as operations on PCollections. + * _SDK_ - A language-specific library for pipeline authors (we often call them + "users" even though we have many kinds of users) to build transforms, + construct their pipelines and submit them to a runner + * _Runner_ - You are going to write a piece of software called a runner that + takes a Beam pipeline and executes it using the capabilities of your data + processing engine. + +These concepts may be very similar to your processing engine's concepts. Since +Beam's design is for cross-language operation and reusable libraries of +transforms, there are some special features worth highlighting. + +### Pipeline + +A pipeline in Beam is a graph of PTransforms operating on PCollections. A +pipeline is constructed by a user in their SDK of choice, and makes its way to +your runner either via the SDK directly or via the Runner API's (forthcoming) +RPC interfaces. + +### PTransforms + +In Beam, a PTransform can be one of the five primitives or it can be a +composite transform encapsulating a subgraph. The primitives are: + + * [_Read_](#implementing-the-read-primitive) - parallel connectors to external + systems + * [_ParDo_](#implementing-the-pardo-primitive) - per element processing + * [_GroupByKey_](#implementing-the-groupbykey-and-window-primitive) - + aggregating elements per key and window + * [_Flatten_](#implementing-the-flatten-primitive) - union of PCollections + * [_Window_](#implementing-the-window-primitive) - set the windowing strategy + for a PCollection Review comment: Note these links don't work. They refer to anchors in the runner contributioin guide where this content came from. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
