comments from arrow

[martindurant]

@pitrou wrote the following on dev@arrow.apache.org

Here are some comments:

• API naming: you seem to favour re-using Unix command-line monickers in
  some places, while using more regular verbs or names in other
  places. I think it should be consistent. Since the Unix
  command-line doesn't exactly cover the exposed functionality, and
  since Unix tends to favour short cryptic names, I think it's better
  to use Python-like naming (which is also more familiar to non-Unix
  users). For example "move" or "rename" or "replace" instead of "mv",
  etc.

• **kwargs parameters: a couple APIs (mkdir, put...) allow passing
  arbitrary parameters, which I assume are intended to be
  backend-specific. It makes it difficult to add other optional
  parameters to those APIs in the future. So I'd make the
  backend-specific directives a single (optional) dict parameter rather
  than a **kwargs.

• invalidate_cache doesn't state whether it invalidates recursively
  or not (recursively sounds better intuitively?). Also, I think it
  would be more flexible to take a list of paths rather than a single
  path.

• du: the effect of the deep parameter isn't obvious to me. I don't
  know what it would mean not to recurse here: what is the size of a
  directory if you don't recurse into it?

• glob may need a formal definition (are trailing slashes
  significant for directory or symlink resolution? this kind of thing),
  though you may want to keep edge cases backend-specific.

• are head and tail at all useful? They can be easily recreated
  using a generic open facility.

• read_block tries to do too much in a single API IMHO, and
  using open directly is more flexible anyway.

• if touch is intended to emulate the Unix API of the same name, the
  docstring should state "Create empty file or update last modification
  timestamp".

• the information dicts returned by several APIs (ls, info....)
  need standardizing, at least for non backend-specific fields.

• if the backend is a networked filesystem with non-trivial latency,
  perhaps the operations would deserve being batched (operate on
  several paths at once), though I will happily defer to your expertise
  on the topic.

[martindurant]

@wesm commented on dev@arrow

https://cwiki.apache.org/confluence/display/ARROW/Python+Filesystems+and+Filesystem+API

I added a JIRA filter and tagged a couple of filesystem-related
issues; there are more that should be added to the list. There's a lot
of other work related to filesystem implementations that we can help
organize and plan here.

As far as refining the details of the API, we should see what's the
best place to collect feedback and discuss. Martin, can you set up a
pull request with the entire patch so that many people can comment and
discuss?

NB: TensorFlow defines a filesystem abstraction, albeit in C++ with
SWIG bindings. We might also look there as a check on some of our
assumptions.

[martindurant]

Martin, can you set up a pull request with the entire patch

@wesm , sorry, I didn't understand this - a PR of which patch to where?

I think I said this previously, I'd be very happy to see everything in this repo be taken over by apache/arrow, if it's at all useful. That might in itself improve conversation. I'm also thoroughly behind amending the file-system APIs I'm involved in to adhere to a consensus design.

The link to TensorFlow is interesting, a fairly different and minimalist take on filesystem functions. I assume that there is no file-like layer (yet), i.e., you can neither grab a file descriptor handle nor pass anything directly to python functions expecting to read from files.

[wesm]

It would be just for the purposes of code review / line-by-line comments. So you could create an empty branch (say based on the repo's initial commit) and then make a PR from HEAD into the empty branch

[martindurant]

#7