Home | About | Sematext search-lucene.com search-hadoop.com
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB
 Search Hadoop and all its subprojects:

Switch to Threaded View
Avro >> mail # dev >> Python-Avro Codegen Proposal


Copy link to this message
-
Re: Python-Avro Codegen Proposal
yes, SpecificCompiler is template driven, but there are a few things that
are specific to the language... like

addStringType, reserved words in the language, how to map avro types to
language specific types.

the changes are pretty minimal, but enough to confuse or overload the class
if made to handle both python and java... in my opinion.

Thanks,
Tal
On Tue, Jun 4, 2013 at 5:16 PM, Philip Zeyliger <[EMAIL PROTECTED]> wrote:

> Thanks!  Please do file the JIRA.
> https://cwiki.apache.org/AVRO/how-to-contribute.html is a guide on
> contributing.
>
> SpecificCompiler is template driven (or was, at some point).  I wonder if
> you could have implemented it by just substituting a different set of
> templates.
>
> Cheers,
>
> -- Philip
>
>
> On Tue, Jun 4, 2013 at 1:54 PM, Tal Levy <[EMAIL PROTECTED]> wrote:
>
> > I will try and clean it up and set up a patch to submit via JIRA
> >
> > 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.
> >
> >
> > let me know what you think
> >
> >
> > On Tue, Jun 4, 2013 at 11:24 AM, Philip Zeyliger <[EMAIL PROTECTED]
> > >wrote:
> >
> > > Hi Tal,
> > >
> > > I would encourage you to file a JIRA and contribute your changes!
> > >
> > > I agree that the generated code approach is a great one for things like
> > RPC
> > > usage, where the schema changes slowly and the extra checking is super
> > > handy.
> > >
> > > -- Philip
> > >
> > >
> > > On Mon, Jun 3, 2013 at 6:28 PM, Stefan Krawczyk <[EMAIL PROTECTED]>
> > > wrote:
> > >
> > > > Hi Tal,
> > > >
> > > > I'm interested in using Avro + Python. That would sound useful, any
> > > chance
> > > > I could have a play with what you've done?
> > > >
> > > > Cheers,
> > > >
> > > > Stefan
> > > >
> > > >
> > > > On Sun, Jun 2, 2013 at 10:28 PM, Tal Levy <[EMAIL PROTECTED]>
> wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > 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
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB