Support cloud storage in load_dataset via fsspec

Closes https://github.com/huggingface/datasets/issues/5281

This PR uses fsspec to support datasets on cloud storage (tested manually with GCS). ETags are currently unsupported for cloud storage. In general, a much larger refactor could be done to just use fsspec for all schemes (ftp, http/s, s3, gcs) to unify the interfaces here, but I ultimately opted to leave that out of this PR

I didn't create a GCS filesystem class in `datasets.filesystems` since the S3 one appears to be a wrapper around `s3fs.S3FileSystem` and mainly used to generate docs.

Comments:
_The documentation is not available anymore as the PR was closed or merged._

> Regarding the tests I think it should be possible to use the mockfs fixture, it allows to play with a dummy fsspec FileSystem with the "mock://" protocol.

> However it requires some storage_options to be passed. Maybe it can be added to DownloadConfig which is passed to cached_path, so that fsspec_get and fsspec_head can use the user's storage_options ?

@lhoestq I went ahead and tested this with a patch so that I could assign the mockfs as a return value. Let me know if I'm missing something though and we need to pass storage_options down

> Instead of patching think it would be better to have a new filesystem TmpDirFileSystem (tmpfs) that doesn't need storage_options for the tests, and that is based on a temporary directory created just for the fixture. Maybe something like this ?

Thanks for the recommendation, this works great.

Feel free to merge `main` into your PR to fix the CI :)

Should be good to go. Thanks!

<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.006183 / 0.011353 (-0.005170) | 0.004180 / 0.011008 (-0.006829) | 0.095965 / 0.038508 (0.057457) | 0.026754 / 0.023109 (0.003645) | 0.339724 / 0.275898 (0.063826) | 0.381628 / 0.323480 (0.058149) | 0.004615 / 0.007986 (-0.003371) | 0.004469 / 0.004328 (0.000140) | 0.074035 / 0.004250 (0.069784) | 0.035089 / 0.037052 (-0.001963) | 0.352253 / 0.258489 (0.093764) | 0.389598 / 0.293841 (0.095757) | 0.032262 / 0.128546 (-0.096285) | 0.011392 / 0.075646 (-0.064254) | 0.323884 / 0.419271 (-0.095388) | 0.042658 / 0.043533 (-0.000874) | 0.331533 / 0.255139 (0.076394) | 0.364723 / 0.283200 (0.081523) | 0.086349 / 0.141683 (-0.055334) | 1.465687 / 1.452155 (0.013533) | 1.559782 / 1.492716 (0.067066) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.198562 / 0.018006 (0.180556) | 0.457170 / 0.000490 (0.456680) | 0.000409 / 0.000200 (0.000209) | 0.000061 / 0.000054 (0.000006) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.022439 / 0.037411 (-0.014973) | 0.096551 / 0.014526 (0.082025) | 0.102230 / 0.176557 (-0.074326) | 0.160878 / 0.737135 (-0.576257) | 0.109348 / 0.296338 (-0.186990) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.456635 / 0.215209 (0.241426) | 4.563571 / 2.077655 (2.485916) | 2.313048 / 1.504120 (0.808928) | 2.117433 / 1.541195 (0.576239) | 2.127478 / 1.468490 (0.658988) | 0.699478 / 4.584777 (-3.885299) | 3.358955 / 3.745712 (-0.386757) | 1.821437 / 5.269862 (-3.448424) | 1.158239 / 4.565676 (-3.407438) | 0.083207 / 0.424275 (-0.341068) | 0.012925 / 0.007607 (0.005318) | 0.556526 / 0.226044 (0.330482) | 5.552364 / 2.268929 (3.283435) | 2.744696 / 55.444624 (-52.699928) | 2.374455 / 6.876477 (-4.502022) | 2.442021 / 2.142072 (0.299949) | 0.809393 / 4.805227 (-3.995834) | 0.152305 / 6.500664 (-6.348359) | 0.066164 / 0.075469 (-0.009305) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.258268 / 1.841788 (-0.583520) | 13.402391 / 8.074308 (5.328083) | 13.816927 / 10.191392 (3.625535) | 0.148466 / 0.680424 (-0.531958) | 0.016487 / 0.534201 (-0.517714) | 0.385888 / 0.579283 (-0.193395) | 0.378840 / 0.434364 (-0.055524) | 0.444527 / 0.540337 (-0.095810) | 0.531011 / 1.386936 (-0.855925) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.006230 / 0.011353 (-0.005123) | 0.004488 / 0.011008 (-0.006520) | 0.077539 / 0.038508 (0.039031) | 0.026611 / 0.023109 (0.003502) | 0.342093 / 0.275898 (0.066195) | 0.371555 / 0.323480 (0.048075) | 0.004665 / 0.007986 (-0.003321) | 0.003289 / 0.004328 (-0.001039) | 0.078378 / 0.004250 (0.074128) | 0.035223 / 0.037052 (-0.001829) | 0.339972 / 0.258489 (0.081483) | 0.378755 / 0.293841 (0.084914) | 0.031331 / 0.128546 (-0.097215) | 0.011406 / 0.075646 (-0.064241) | 0.086891 / 0.419271 (-0.332381) | 0.047713 / 0.043533 (0.004180) | 0.342678 / 0.255139 (0.087539) | 0.364536 / 0.283200 (0.081337) | 0.092132 / 0.141683 (-0.049551) | 1.537050 / 1.452155 (0.084895) | 1.639927 / 1.492716 (0.147211) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.219933 / 0.018006 (0.201927) | 0.391627 / 0.000490 (0.391137) | 0.002238 / 0.000200 (0.002038) | 0.000072 / 0.000054 (0.000018) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.024890 / 0.037411 (-0.012521) | 0.098989 / 0.014526 (0.084464) | 0.104505 / 0.176557 (-0.072052) | 0.156252 / 0.737135 (-0.580884) | 0.108027 / 0.296338 (-0.188312) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.443957 / 0.215209 (0.228748) | 4.450850 / 2.077655 (2.373196) | 2.076043 / 1.504120 (0.571923) | 1.866396 / 1.541195 (0.325202) | 1.902692 / 1.468490 (0.434202) | 0.703160 / 4.584777 (-3.881617) | 3.373761 / 3.745712 (-0.371951) | 2.615649 / 5.269862 (-2.654213) | 1.340612 / 4.565676 (-3.225065) | 0.083836 / 0.424275 (-0.340439) | 0.012619 / 0.007607 (0.005012) | 0.553410 / 0.226044 (0.327365) | 5.526500 / 2.268929 (3.257571) | 2.513213 / 55.444624 (-52.931411) | 2.152701 / 6.876477 (-4.723776) | 2.165092 / 2.142072 (0.023019) | 0.818381 / 4.805227 (-3.986846) | 0.152118 / 6.500664 (-6.348546) | 0.066950 / 0.075469 (-0.008519) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.291468 / 1.841788 (-0.550320) | 13.694828 / 8.074308 (5.620520) | 13.821019 / 10.191392 (3.629627) | 0.126077 / 0.680424 (-0.554347) | 0.016543 / 0.534201 (-0.517658) | 0.381399 / 0.579283 (-0.197884) | 0.377326 / 0.434364 (-0.057038) | 0.439275 / 0.540337 (-0.101063) | 0.524021 / 1.386936 (-0.862915) |

</details>
</details>

![](https://cml.dev/watermark.png#3e6269979fc80ae8939294d26298897f0db5b84d "CML watermark")


@dwyatte 
> (tested manually with GCS)

Can you please paste the code you used to test this with? It's not clear how one would go about actually using this to access datasets in Google Cloud Storage or S3.

@Xe 

With GCS, this can be completely seamless if you have an activated set of credentials with access to the file (which is how I use the functionality). You should be able to pass `storage_options` with credentials too

```
dwyatte-mac:tmp dwyatte$ gcloud auth list
     Credentialed Accounts
ACTIVE  ACCOUNT
*       [YOUR_EMAIL]
```

```
In [1]: from datasets import load_dataset
   ...: 
   ...: dataset = load_dataset("parquet", data_files="gs://path/to/file.pq")

Downloading data: 100%|████████████████████████████████████████| 26.5M/26.5M [00:01<00:00, 20.7MB/s]
Generating train split: 2000 examples [00:00, 26434.38 examples/s]
```