[C++] Filesystems: detect if URI is passed where a file path is required and raise informative error

[asfimport]

Currently, when passing a URI to a filesystem method (except for from_uri) or other functions that accept a filesystem object, you can get a rather cryptic error message (eg in this case about "No response body" for S3, in the example below).

Ideally, the filesystem object knows its own prefix "scheme", and so can detect if a user is passing a URI instead of file path, and we can provide a nicer error message.

Example with S3:

>>> from pyarrow.fs import S3FileSystem
>>> fs = S3FileSystem(region="us-east-2")
>>> fs.get_file_info('s3://ursa-labs-taxi-data/2016/01/')
...
OSError: When getting information for key '/ursa-labs-taxi-data/2016/01' in bucket 's3:': AWS Error [code 100]: No response body.

>>> import pyarrow.parquet as pq
>>> table = pq.read_table('s3://ursa-labs-taxi-data/2016/01/data.parquet', filesystem=fs)
...
OSError: When getting information for key '/ursa-labs-taxi-data/2016/01/data.parquet' in bucket 's3:': AWS Error [code 100]: No response body.

With a local filesystem, you actually get a not found file:

>>> fs = LocalFileSystem()
>>> fs.get_file_info("file:///home")
<FileInfo for 'file:///home': type=FileType.NotFound>

cc @pitrou

Reporter: Joris Van den Bossche / @jorisvandenbossche
Assignee: Antoine Pitrou / @pitrou

Related issues:

• [Python] ArrowInvalid error on reading partitioned parquet files from S3 (arrow-2.0.0) (is related to)

PRs and other links:

• GitHub Pull Request #11997

_{Note: This issue was originally created as ARROW-10998. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
@jorisvandenbossche Is this something you want to do for 3.0.0?

[asfimport]

Antoine Pitrou / @pitrou:
@ianmcook Are you still planning to work on this?

[asfimport]

Ian Cook / @ianmcook:
@pitrou  I do not have immediate plans to work on this. I have un-assigned myself.

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 11997
#11997