[jira] [Updated] (ARROW-3916) [Python] Support caller-provided filesystem in `ParquetWriter` constructor

["Wes McKinney (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-3916?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Wes McKinney updated ARROW-3916:
--------------------------------
    Fix Version/s:     (was: 0.13.0)
                   0.12.0

> [Python] Support caller-provided filesystem in `ParquetWriter` constructor
> --------------------------------------------------------------------------
>
>                 Key: ARROW-3916
>                 URL: https://issues.apache.org/jira/browse/ARROW-3916
>             Project: Apache Arrow
>          Issue Type: New Feature
>          Components: Python
>    Affects Versions: 0.11.1
>            Reporter: Mackenzie
>            Priority: Major
>              Labels: parquet
>             Fix For: 0.12.0
>
>
> Currently to write files incrementally to S3, the following pattern appears necessary:
> {{def write_dfs_to_s3(dfs, fname):}}
> {{    first_df = dfs[0]}}
> {{    table = pa.Table.from_pandas(first_df, preserve_index=False)}}
> {{    fs = s3fs.S3FileSystem()}}
> {{    fh = fs.open(fname, 'wb')}}
> {{    with pq.ParquetWriter(fh, table.schema) as writer:}}
> {{         # set file handle on writer so writer manages closing it when it is itself closed}}
> {{        writer.file_handle = fh}}
> {{        writer.write_table(table=table)}}
> {{        for df in dfs[1:]:}}
> {{            table = pa.Table.from_pandas(df, preserve_index=False)}}
> {{            writer.write_table(table=table)}}
> This works as expected, but is quite roundabout. It would be much easier if `ParquetWriter` supported `filesystem` as a keyword argument in its constructor, in which case the `_get_fs_from_path` would be overriden by the usual pattern of using the kwarg after ensuring it is a proper file system with `_ensure_filesystem`.



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