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https://issues.apache.org/jira/browse/AVRO-1345?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13738579#comment-13738579
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Doug Cutting commented on AVRO-1345:
------------------------------------
This looks great. Tests pass for me.
A few concerns I have before we commit this:
- Can we please avoid incompatibly changing the command line for
SpecificCompilerTool? Perhaps we should add a -lang option that defaults to
'java'.
- Shouldn't we add some tests of the generated Python code? We might just add
tests in the python tree that refer to
../../lang/java/tools/src/test/compiler/output/*.py, or we could move these
into share/test.
- We might add something to the Python "getting started" guide about this.
> Python Codegen
> --------------
>
> Key: AVRO-1345
> URL: https://issues.apache.org/jira/browse/AVRO-1345
> Project: Avro
> Issue Type: New Feature
> Components: java, python
> Reporter: Tal Levy
> Attachments: AVRO-1345.patch
>
>
> I recently started using Avro at my work and we found it difficult to keep
> track of what python dict matched to what schema. Instead of having
> random dicts being populated and then attempted to be serialized to avro, I
> thought
> it would be more readable and less error prone to codegen the python dict
> for developers. These classes are type checked field by field. Although it
> does not
> have the advantage of compiled type checking like in the java codegen, it is
> a
> friendly wrapper around python dicts representing avro records to be
> serialized.
> let me know what you think about this, I am still tweaking how it behaves.
> I understand it is a bit unpythonic to enforce types in this way, but the
> readability
> is worth it nonetheless.
> here is an example record:
> https://gist.github.com/talevy/5696236
> I extended the avro compiler/tools to provide both java and python codegen
> functionality.
> so if this sounds like something others would use, maybe it makes sense to
> include it
> into the main repo.
> here are the changes
> https://github.com/talevy/avro/tree/python-codegen
> a few caveats and thoughts about my current version:
> 1. I do not know how to best handle constructors, because some fields are not
> allowed to be null... maybe a builder pattern would work here, but it's kind
> of weird in python
> 2. I copy/pasted a lot of the code from SpecificCompiler to make the
> PythonCompiler... some renaming and code re-use via inheritance would make it
> read better.
> 3. I wanted to reuse the validate methods provided already in Avro to verify
> the record, but it takes away from some of the class type correctness for
> nested records and such.
> 4. I do not know what the best way of outputing multiple files is, I
> currently use the same packaging as the java classes into their namespace
> directories
> 5. I am not familiar with the avro-protocol format, so I only implemented
> enums and records.
> I updated the SpecificCompilerTool to have the following usage
> ```
> "Usage: [-string] (schema|protocol) (python|java) input... outputdir"
> ````
> So generating the python classes is as easy as java.
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