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https://issues.apache.org/jira/browse/BEAM-9679?focusedWorklogId=447294&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-447294
]
ASF GitHub Bot logged work on BEAM-9679:
----------------------------------------
Author: ASF GitHub Bot
Created on: 17/Jun/20 14:08
Start Date: 17/Jun/20 14:08
Worklog Time Spent: 10m
Work Description: henryken commented on a change in pull request #12024:
URL: https://github.com/apache/beam/pull/12024#discussion_r441564315
##########
File path: learning/katas/go/Core Transforms/Side Input/Side Input/task.md
##########
@@ -0,0 +1,68 @@
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one
+ or more contributor license agreements. See the NOTICE file
+ distributed with this work for additional information
+ regarding copyright ownership. The ASF licenses this file
+ to you 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.
+-->
+
+# Side Input
+
+In addition to the main input PCollection, you can provide additional inputs
to a ParDo transform
+in the form of side inputs. A side input is an additional input that your DoFn
can access each time
+it processes an element in the input PCollection. When you specify a side
input, you create a view
+of some other data that can be read from within the ParDo transform’s DoFn
while processing each
+element.
+
+Side inputs are useful if your ParDo needs to inject additional data when
processing each element
+in the input PCollection, but the additional data needs to be determined at
runtime (and not
+hard-coded). Such values might be determined by the input data, or depend on a
different branch of
+your pipeline.
+
+**Kata:** Please enrich each Person with the country based on the city he/she
lives in.
+
+<div class="hint">
+ Use <a
href="https://godoc.org/github.com/apache/beam/sdks/go/pkg/beam#hdr-Side_Inputs";>
+ beam.SideInput</a> to create a side input of the citiesToCountries
PCollection
+</div>
+
+<div class="hint">
+ Use <a
href="https://godoc.org/github.com/apache/beam/sdks/go/pkg/beam#ParDo";>
+ beam.ParDo</a> with a DoFn that accepts a
+ <a
href="https://godoc.org/github.com/apache/beam/sdks/go/pkg/beam#hdr-Side_Inputs";>
+ beam.SideInput</a>.
+</div>
+
+<div class="hint">
+ Refer to the Beam Programming Guide
+ <a
href="https://beam.apache.org/documentation/programming-guide/#side-inputs";>"Side
inputs"</a>
+ section for more information.
+</div>
+
+<div class="hint">
+ A ParDo that has a PCollection KV as side input expects a DoFn that looks
like the following.
+
+ ```
Review comment:
This code snippet needs to have no indentation to render properly.
##########
File path: learning/katas/go/Core Transforms/Side Input/Side
Input/pkg/task/task.go
##########
@@ -0,0 +1,45 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You 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.
+
+package task
+
+import (
+ "github.com/apache/beam/sdks/go/pkg/beam"
+)
+
+type Person struct {
+ Name, City, Country string
+}
+
+func ApplyTransform(s beam.Scope, personsKV beam.PCollection,
citiesToCountries beam.PCollection) beam.PCollection {
+ citiesToCountriesView := beam.SideInput{
+ Input: citiesToCountries,
+ }
+ return beam.ParDo(s, joinFn, personsKV, citiesToCountriesView)
+}
+
+func joinFn(person Person, citiesToCountriesIter func(*string, *string) bool,
emit func(Person)) {
+ var city, country string
+ for citiesToCountriesIter(&city, &country) {
Review comment:
Is there a way to use a KV-like API (e.g. get(key)) instead of iterating
each of the KV pair?
The way this works seems like a List collection with a tuple.
Or probably the naming KV is misleading?
##########
File path: learning/katas/go/Core Transforms/Side Input/Side
Input/pkg/task/task.go
##########
@@ -0,0 +1,45 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You 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.
+
+package task
+
+import (
+ "github.com/apache/beam/sdks/go/pkg/beam"
+)
+
+type Person struct {
+ Name, City, Country string
+}
+
+func ApplyTransform(s beam.Scope, personsKV beam.PCollection,
citiesToCountries beam.PCollection) beam.PCollection {
+ citiesToCountriesView := beam.SideInput{
+ Input: citiesToCountries,
+ }
+ return beam.ParDo(s, joinFn, personsKV, citiesToCountriesView)
+}
+
+func joinFn(person Person, citiesToCountriesIter func(*string, *string) bool,
emit func(Person)) {
+ var city, country string
+ for citiesToCountriesIter(&city, &country) {
+ if person.City == city {
+ emit(Person{
+ Name: person.Name,
+ City: city,
+ Country: country,
+ })
Review comment:
Add `break` statement here?
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Issue Time Tracking
-------------------
Worklog Id: (was: 447294)
Time Spent: 12h 20m (was: 12h 10m)
> Core Transforms | Go SDK Code Katas
> -----------------------------------
>
> Key: BEAM-9679
> URL: https://issues.apache.org/jira/browse/BEAM-9679
> Project: Beam
> Issue Type: Sub-task
> Components: katas, sdk-go
> Reporter: Damon Douglas
> Assignee: Damon Douglas
> Priority: P2
> Time Spent: 12h 20m
> Remaining Estimate: 0h
>
> A kata devoted to core beam transforms patterns after
> [https://github.com/apache/beam/tree/master/learning/katas/java/Core%20Transforms]
> where the take away is an individual's ability to master the following using
> an Apache Beam pipeline using the Golang SDK.
>
> ||Transform||Pull Request||Status||
> |Map|[11564|https://github.com/apache/beam/pull/11564]|Closed|
> |GroupByKey|[11734|https://github.com/apache/beam/pull/11734]|Closed|
> |CoGroupByKey|[11803|https://github.com/apache/beam/pull/11803]|Closed|
> |Combine Simple
> Function|[11866|https://github.com/apache/beam/pull/11866]|Closed|
> |CombineFn|[11883|https://github.com/apache/beam/pull/11883]|Closed|
> |CombinePerKey|[11936|https://github.com/apache/beam/pull/11936]|Closed|
> |Flatten|[11806|https://github.com/apache/beam/pull/11806]|Closed|
> |Partition|[11979|https://github.com/apache/beam/pull/11979]|Closed|
> |Side Input|[12024|https://github.com/apache/beam/pull/12024]|Open|
> |Side Output| | |
> |Branching| | |
> |Composite Transform| | |
> |DoFn Additional Parameters| | |
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