cloud-file

Simple reading of cloud files in Rust

Highlights

• HTTP, AWS S3, Azure, Google, or local
• Sequential or random access
• Simplifies use of the powerful object_store crate, focusing on a useful subset of its features
• Access files via URLs and string-based options
• Read binary or text
• Fully async
• Used by genomics crate BedReader, which is used by other Rust and Python projects
• Also see Nine Rules for Accessing Cloud Files from Your Rust Code Practical Lessons from Upgrading Bed-Reader, a Bioinformatics Library in Towards Data Science.

Install

cargo add cloud-file

Examples

Find the size of a cloud file.

use cloud_file::CloudFile;
# Runtime::new().unwrap().block_on(async {  // '#' needed for doctest

let url = "https://raw.githubusercontent.com/fastlmm/bed-sample-files/main/toydata.5chrom.fam";
let cloud_file = CloudFile::new(url)?;
let file_size = cloud_file.read_file_size().await?;
assert_eq!(file_size, 14_361);
# Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
# use {cloud_file::CloudFileError, tokio::runtime::Runtime};

Find the number of lines in a cloud file.

use cloud_file::CloudFile;
use futures::StreamExt; // Enables `.next()` on streams.
# Runtime::new().unwrap().block_on(async { // '#' needed for doctest

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);
# Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
# use {cloud_file::CloudFileError, tokio::runtime::Runtime};   

More examples

Project Links

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