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Posted to github@beam.apache.org by GitBox <gi...@apache.org> on 2021/09/30 23:24:02 UTC
[GitHub] [beam] lostluck opened a new pull request #15632: [BEAM-12513] Schemas and Coders
lostluck opened a new pull request #15632:
URL: https://github.com/apache/beam/pull/15632
Add documentation around Beam Schemas and coders to the BPG.
One aspect was less convenient than it should have been so I also expanded the functionality to unify the approach for both interface and non-interface struct types.
------------------------
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`ValidatesRunner` compliance status (on master branch)
--------------------------------------------------------
<table>
<thead>
<tr>
<th>Lang</th>
<th>ULR</th>
<th>Dataflow</th>
<th>Flink</th>
<th>Samza</th>
<th>Spark</th>
<th>Twister2</th>
</tr>
</thead>
<tbody>
<tr>
<td>Go</td>
<td>---</td>
<td>
<a href="https://ci-beam.apache.org/job/beam_PostCommit_Go/lastCompletedBuild/">
<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Go/lastCompletedBuild/badge/icon">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Go_VR_Samza/lastCompletedBuild/badge/icon">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Go_VR_Spark/lastCompletedBuild/badge/icon">
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<td>---</td>
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<tr>
<td>Java</td>
<td>
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Java_PVR_Spark_Batch/lastCompletedBuild/badge/icon?subject=Portable">
</a><br>
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Java_ValidatesRunner_SparkStructuredStreaming/lastCompletedBuild/badge/icon?subject=Structured+Streaming">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Java_ValidatesRunner_Twister2/lastCompletedBuild/badge/icon">
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<td>Python</td>
<td>---</td>
<td>
<a href="https://ci-beam.apache.org/job/beam_PostCommit_Py_VR_Dataflow/lastCompletedBuild/">
<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Py_VR_Dataflow/lastCompletedBuild/badge/icon?subject=V1">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PreCommit_Python_PVR_Flink_Cron/lastCompletedBuild/badge/icon?subject=Portable">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Python_VR_Flink/lastCompletedBuild/badge/icon">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Python_VR_Samza/lastCompletedBuild/badge/icon">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Python_VR_Spark/lastCompletedBuild/badge/icon">
</a>
</td>
<td>---</td>
</tr>
<tr>
<td>XLang</td>
<td>
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_XVR_Direct/lastCompletedBuild/badge/icon">
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<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_XVR_Spark/lastCompletedBuild/badge/icon">
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</td>
<td>---</td>
</tr>
</tbody>
</table>
Examples testing status on various runners
--------------------------------------------------------
<table>
<thead>
<tr>
<th>Lang</th>
<th>ULR</th>
<th>Dataflow</th>
<th>Flink</th>
<th>Samza</th>
<th>Spark</th>
<th>Twister2</th>
</tr>
</thead>
<tbody>
<tr>
<td>Go</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
</tr>
<tr>
<td>Java</td>
<td>---</td>
<td>
<a href="https://ci-beam.apache.org/job/beam_PreCommit_Java_Examples_Dataflow_Cron/lastCompletedBuild/">
<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PreCommit_Java_Examples_Dataflow_Cron/lastCompletedBuild/badge/icon?subject=V1">
</a><br>
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</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
</tr>
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<td>Python</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
</tr>
<tr>
<td>XLang</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
<td>---</td>
</tr>
</tbody>
</table>
Post-Commit SDK/Transform Integration Tests Status (on master branch)
------------------------------------------------------------------------------------------------
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<th>Go</th>
<th>Java</th>
<th>Python</th>
</tr>
</thead>
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<td>
<a href="https://ci-beam.apache.org/job/beam_PostCommit_Go/lastCompletedBuild/">
<img alt="Build Status" src="https://ci-beam.apache.org/job/beam_PostCommit_Go/lastCompletedBuild/badge/icon">
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Pre-Commit Tests Status (on master branch)
------------------------------------------------------------------------------------------------
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<th>---</th>
<th>Java</th>
<th>Python</th>
<th>Go</th>
<th>Website</th>
<th>Whitespace</th>
<th>Typescript</th>
</tr>
</thead>
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<td>Non-portable</td>
<td>
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<td>Portable</td>
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<td>---</td>
<td>---</td>
<td>---</td>
</tr>
</tbody>
</table>
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[GitHub] [beam] jrmccluskey commented on a change in pull request #15632: [BEAM-12513] Schemas and Coders
Posted by GitBox <gi...@apache.org>.
jrmccluskey commented on a change in pull request #15632:
URL: https://github.com/apache/beam/pull/15632#discussion_r720287476
##########
File path: website/www/site/content/en/documentation/programming-guide.md
##########
@@ -2666,6 +2666,11 @@ infer the correct schema based on the members of the class.
In Python you can use the following set of classes to represent the purchase schema. Beam will automatically infer the correct schema based on the members of the class.
{{< /paragraph >}}
+{{< paragraph class="language-go" >}}
+In Go, schema encoding used by default for struct types, with Exported fields becoming part of the schema.
Review comment:
Is there a word missing here?
##########
File path: website/www/site/content/en/documentation/programming-guide.md
##########
@@ -3191,13 +3264,63 @@ output_pc = input_pc | beam.Map(lambda item: beam.Row(bank=str(item["bank"]),
purchase_amount=float(item["purchase_amount"])))
{{< /highlight >}}
+{{< paragraph class="language-go" >}}
+Beam currently only infers schemas for exported fields in Go structs.
+{{< /paragraph >}}
+
+{{< paragraph class="language-go" >}}
+**Structs**
+{{< /paragraph >}}
+
+{{< paragraph class="language-go" >}}
+Beam will automatically infer schemas for all Go structs used
+as PCollection elements, and default to encoding them using
+schema encoding.
+{{< /paragraph >}}
+
+{{< highlight go >}}
+type Transaction struct{
+ Bank string
+ PurchaseAmount float64
+
+ checksum []byte // ignored
+}
+{{< /highlight >}}
+
+{{< paragraph class="language-go" >}}
+Unexported fields are ignored, and cannot be automatically infered as part of the schema.
+Fields of type func, channel, unsafe.Pointer, or uintptr will be ignored by inference.
+Fields of interface types are ignored, unless a schema provider
+is registered for them.
+{{< /paragraph >}}
+
+{{< paragraph class="language-go" >}}
+By default, schema field names will match the exported struct field names.
+In the above example, "Bank" and "PurchaseAmount" are the schema field names.
+A schema field name can be overridden with a struct tag for the field.
+{{< /paragraph >}}
+
+{{< highlight go >}}
+type Transaction struct{
+ Bank string `beam:"bank"`
+ PurchaseAmount float64 `beam:"purchase_amount"`
+}
+{{< /highlight >}}
+
+{{< paragraph class="language-go" >}}
+Overriding schema field names is useful for compatibility cross language transforms.
Review comment:
Is it worth elaborating on this point a bit or linking to documentation that does? This line being stand-alone in its current context doesn't convey much information.
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[GitHub] [beam] lostluck commented on pull request #15632: [BEAM-12513] Schemas and Coders
Posted by GitBox <gi...@apache.org>.
lostluck commented on pull request #15632:
URL: https://github.com/apache/beam/pull/15632#issuecomment-931817493
R: @youngoli @riteshghorse @jrmccluskey
Big wall of text. I'm going to do more passes myself on checking things myself, but this is worth a go.
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[GitHub] [beam] lostluck merged pull request #15632: [BEAM-12513] Schemas and Coders
Posted by GitBox <gi...@apache.org>.
lostluck merged pull request #15632:
URL: https://github.com/apache/beam/pull/15632
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[GitHub] [beam] lostluck commented on a change in pull request #15632: [BEAM-12513] Schemas and Coders
Posted by GitBox <gi...@apache.org>.
lostluck commented on a change in pull request #15632:
URL: https://github.com/apache/beam/pull/15632#discussion_r720618557
##########
File path: website/www/site/content/en/documentation/programming-guide.md
##########
@@ -3191,13 +3264,63 @@ output_pc = input_pc | beam.Map(lambda item: beam.Row(bank=str(item["bank"]),
purchase_amount=float(item["purchase_amount"])))
{{< /highlight >}}
+{{< paragraph class="language-go" >}}
+Beam currently only infers schemas for exported fields in Go structs.
+{{< /paragraph >}}
+
+{{< paragraph class="language-go" >}}
+**Structs**
+{{< /paragraph >}}
+
+{{< paragraph class="language-go" >}}
+Beam will automatically infer schemas for all Go structs used
+as PCollection elements, and default to encoding them using
+schema encoding.
+{{< /paragraph >}}
+
+{{< highlight go >}}
+type Transaction struct{
+ Bank string
+ PurchaseAmount float64
+
+ checksum []byte // ignored
+}
+{{< /highlight >}}
+
+{{< paragraph class="language-go" >}}
+Unexported fields are ignored, and cannot be automatically infered as part of the schema.
+Fields of type func, channel, unsafe.Pointer, or uintptr will be ignored by inference.
+Fields of interface types are ignored, unless a schema provider
+is registered for them.
+{{< /paragraph >}}
+
+{{< paragraph class="language-go" >}}
+By default, schema field names will match the exported struct field names.
+In the above example, "Bank" and "PurchaseAmount" are the schema field names.
+A schema field name can be overridden with a struct tag for the field.
+{{< /paragraph >}}
+
+{{< highlight go >}}
+type Transaction struct{
+ Bank string `beam:"bank"`
+ PurchaseAmount float64 `beam:"purchase_amount"`
+}
+{{< /highlight >}}
+
+{{< paragraph class="language-go" >}}
+Overriding schema field names is useful for compatibility cross language transforms.
Review comment:
Elaborated a bit. Going to merge this in, things are generally easier to understand in rendered form, and it's easy enough to make spot fixes later.
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[GitHub] [beam] lostluck commented on a change in pull request #15632: [BEAM-12513] Schemas and Coders
Posted by GitBox <gi...@apache.org>.
lostluck commented on a change in pull request #15632:
URL: https://github.com/apache/beam/pull/15632#discussion_r720376795
##########
File path: website/www/site/content/en/documentation/programming-guide.md
##########
@@ -2666,6 +2666,11 @@ infer the correct schema based on the members of the class.
In Python you can use the following set of classes to represent the purchase schema. Beam will automatically infer the correct schema based on the members of the class.
{{< /paragraph >}}
+{{< paragraph class="language-go" >}}
+In Go, schema encoding used by default for struct types, with Exported fields becoming part of the schema.
Review comment:
Nice catch! the missing word was "is". ...encoding is used by....
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