Struct cloud_file::CloudFile

pub struct CloudFile {
    pub cloud_service: Arc<DynObjectStore>,
    pub store_path: StorePath,
}

The main struct representing the location of a file in the cloud.

It is constructed with CloudFile::new. It is, by design, cheap to clone.

Internally, it stores two pieces of information: the file’s cloud service and the path to the file on that service.

Examples

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bed";
let cloud_file = CloudFile::new(url)?;
assert_eq!(cloud_file.read_file_size().await?, 303);

Fields

cloud_service: Arc<DynObjectStore>

A cloud service, for example, Http, AWS S3, Azure, the local file system, etc. Under the covers, it is an Arc-wrapped DynObjectStore. The DynObjectStore, in turn, holds an ObjectStore from the powerful object_store crate.

store_path: StorePath

A path to a file on the cloud service. Under the covers, StorePath is an alias for a Path in the object_store crate.

Implementations

impl CloudFile

pub fn new(location: impl AsRef<str>) -> Result<CloudFile, CloudFileError>

Create a new CloudFile from a URL string.

Example

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bed";
let cloud_file = CloudFile::new(url)?;
assert_eq!(cloud_file.read_file_size().await?, 303);

pub fn new_with_options<I, K, V>( location: impl AsRef<str>, options: I ) -> Result<CloudFile, CloudFileError>

where I: IntoIterator<Item = (K, V)>, K: AsRef<str>, V: Into<String>,

Create a new CloudFile from a URL string and options.

Example

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bed";
let cloud_file = CloudFile::new_with_options(url, [("timeout", "30s")])?;
assert_eq!(cloud_file.read_file_size().await?, 303);

pub async fn count_lines(&self) -> Result<usize, CloudFileError>

Count the lines in a file stored in the cloud.

Example

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.fam";
let cloud_file = CloudFile::new(url)?;
assert_eq!(cloud_file.count_lines().await?, 10);

pub async fn read_file_size(&self) -> Result<usize, CloudFileError>

Return the size of a file stored in the cloud.

Example

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bed";
let cloud_file = CloudFile::new(url)?;
assert_eq!(cloud_file.read_file_size().await?, 303);

pub async fn read_range( &self, range: Range<usize> ) -> Result<Bytes, CloudFileError>

Return the Bytes from a specified range.

Example

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bim";
let cloud_file = CloudFile::new(url)?;
let bytes = cloud_file.read_range((0..10)).await?;
assert_eq!(bytes.as_ref(), b"1\t1:1:A:C\t");

pub async fn read_ranges( &self, ranges: &[Range<usize>] ) -> Result<Vec<Bytes>, CloudFileError>

Return the Vec of Bytes from specified ranges.

Example

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bim";
let cloud_file = CloudFile::new(url)?;
let bytes_vec = cloud_file.read_ranges(&[0..10, 1000..1010]).await?;
assert_eq!(bytes_vec.len(), 2);
assert_eq!(bytes_vec[0].as_ref(), b"1\t1:1:A:C\t");
assert_eq!(bytes_vec[1].as_ref(), b":A:C\t0.0\t4");

pub async fn get_opts( &self, get_options: GetOptions ) -> Result<GetResult, CloudFileError>

Call the object_store crate’s get_opts method.

You can, for example, in one call retrieve a range of bytes from the file and the file’s metadata. The result is a GetResult.

Example

In one call, read the first three bytes of a genomic data file and get the size of the file. Check that the file starts with the expected file signature.

use cloud_file::CloudFile;
use object_store::{GetRange, GetOptions};

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bed";
let cloud_file = CloudFile::new(url)?;
let get_options = GetOptions {
    range: Some(GetRange::Bounded(0..3)),
    ..Default::default()
};
let get_result = cloud_file.get_opts(get_options).await?;
let size: usize = get_result.meta.size;
let bytes = get_result
    .bytes()
    .await?;
assert_eq!(bytes[0], 0x6c);
assert_eq!(bytes[1], 0x1b);
assert_eq!(bytes[2], 0x01);
assert_eq!(size, 303);

pub async fn read_range_and_file_size( &self, range: Range<usize> ) -> Result<(Bytes, usize), CloudFileError>

Retrieve the Bytes from a specified range & the file’s size.

Example

In one call, read the first three bytes of a genomic data file and get the size of the file. Check that the file starts with the expected file signature.

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bed";
let cloud_file = CloudFile::new(url)?;
let (bytes, size) = cloud_file.read_range_and_file_size (0..3).await?;
assert_eq!(bytes[0], 0x6c);
assert_eq!(bytes[1], 0x1b);
assert_eq!(bytes[2], 0x01);
assert_eq!(size, 303);

pub async fn get(&self) -> Result<GetResult, CloudFileError>

Call the object_store crate’s get method.

The result is a GetResult which can, for example, be converted into a stream of bytes.

Example

Do a ‘get’, turn result into a stream, then scan all the bytes of the file for the newline character.

use cloud_file::CloudFile;
use futures_util::StreamExt;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/toydata.5chrom.fam";
let cloud_file = CloudFile::new_with_options(url, [("timeout", "30s")])?;
let mut stream = cloud_file.get().await?.into_stream();
let mut newline_count: usize = 0;
while let Some(bytes) = stream.next().await {
    let bytes = bytes?;
    newline_count += bytecount::count(&bytes, b'\n');
    }
assert_eq!(newline_count, 500);

pub async fn read_all(&self) -> Result<Bytes, CloudFileError>

Read the whole file into an in-memory Bytes.

Example

Read the whole file, then scan all the bytes of the for the newline character.

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/toydata.5chrom.fam";
let cloud_file = CloudFile::new_with_options(url, [("timeout", "30s")])?;
let all = cloud_file.read_all().await?;
let newline_count = bytecount::count(&all, b'\n');
assert_eq!(newline_count, 500);

pub async fn stream_chunks( &self ) -> Result<BoxStream<'static, Result<Bytes>>, CloudFileError>

Retrieve the file’s contents as a stream of Bytes.

Example

Open the file as a stream of bytes, then scan all the bytes for the newline character.

use cloud_file::CloudFile;
use futures::StreamExt; // Enables `.next()` on streams.

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/toydata.5chrom.fam";
let cloud_file = CloudFile::new_with_options(url, [("timeout", "30s")])?;
let mut chunks = cloud_file.stream_chunks().await?;
let mut newline_count: usize = 0;
while let Some(chunk) = chunks.next().await {
    let chunk = chunk?;
    newline_count += bytecount::count(&chunk, b'\n');
    }
assert_eq!(newline_count, 500);

pub async fn stream_line_chunks( &self ) -> Result<BoxStream<'static, Result<Bytes>>, CloudFileError>

Retrieve the file’s contents as a stream of Bytes, each containing one or more whole lines.

Example

Return the 12th line of a file.

use cloud_file::CloudFile;
use futures::StreamExt; // Enables `.next()` on streams.
use std::str::from_utf8;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/toydata.5chrom.fam";
let goal_index = 12;

let cloud_file = CloudFile::new(url)?;
let mut line_chunks = cloud_file.stream_line_chunks().await?;
let mut index_iter = 0..;
let mut goal_line = None;
'outer_loop: while let Some(line_chunk) = line_chunks.next().await {
    let line_chunk = line_chunk?;
    let lines = from_utf8(&line_chunk)?.split_terminator('\n');
    for line in lines {
        let index = index_iter.next().unwrap(); // Safe because the iterator is infinite
        if index == goal_index {
            goal_line = Some(line.to_string());
            break 'outer_loop;
        }
    }
}
assert_eq!(goal_line, Some("per12 per12 0 0 2 -0.0382707".to_string()));

pub fn set_extension(&mut self, extension: &str) -> Result<(), CloudFileError>

Change the CloudFile’s extension (in place).

It removes the current extension, if any. It appends the given extension, if any.

The method is in-place rather than functional to make it consistent with std::path::PathBuf::set_extension.

Example

use cloud_file::CloudFile;

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/plink_sim_10s_100v_10pmiss.bed";
let mut cloud_file = CloudFile::new(url)?;
assert_eq!(cloud_file.read_file_size().await?, 303);
cloud_file.set_extension("fam")?;
assert_eq!(cloud_file.read_file_size().await?, 130);

Trait Implementations

impl Clone for CloudFile

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CloudFile

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for CloudFile

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.