Trait MultipartWrite 

pub trait MultipartWrite:
    Send
    + Sync
    + Unpin
    + 'static {
    // Required methods
    fn write_once(
        &self,
        size: u64,
        body: Buffer,
    ) -> impl Future<Output = Result<Metadata>> + MaybeSend;
    fn initiate_part(&self) -> impl Future<Output = Result<String>> + MaybeSend;
    fn write_part(
        &self,
        upload_id: &str,
        part_number: usize,
        size: u64,
        body: Buffer,
    ) -> impl Future<Output = Result<MultipartPart>> + MaybeSend;
    fn complete_part(
        &self,
        upload_id: &str,
        parts: &[MultipartPart],
    ) -> impl Future<Output = Result<Metadata>> + MaybeSend;
    fn abort_part(
        &self,
        upload_id: &str,
    ) -> impl Future<Output = Result<()>> + MaybeSend;
}

MultipartWrite is used to implement oio::Write based on multipart uploads. By implementing MultipartWrite, services don’t need to care about the details of uploading parts.

Architecture

The architecture after adopting MultipartWrite:

• Services impl MultipartWrite
• MultipartWriter impl Write
• Expose MultipartWriter as Accessor::Writer

Notes

MultipartWrite has an oneshot optimization when write has been called only once:

w.write(bs).await?;
w.close().await?;

We will use write_once instead of starting a new multipart upload.

Requirements

Services that implement BlockWrite must fulfill the following requirements:

• Must be a http service that could accept AsyncBody.
• Don’t need initialization before writing.
• Block ID is generated by caller BlockWrite instead of services.
• Complete block by an ordered block id list.

Required Methods

fn write_once( &self, size: u64, body: Buffer, ) -> impl Future<Output = Result<Metadata>> + MaybeSend

write_once is used to write the data to underlying storage at once.

MultipartWriter will call this API when:

• All the data has been written to the buffer and we can perform the upload at once.

fn initiate_part(&self) -> impl Future<Output = Result<String>> + MaybeSend

initiate_part will call start a multipart upload and return the upload id.

MultipartWriter will call this when:

• the total size of data is unknown.
• the total size of data is known, but the size of current write is less than the total size.

fn write_part( &self, upload_id: &str, part_number: usize, size: u64, body: Buffer, ) -> impl Future<Output = Result<MultipartPart>> + MaybeSend

write_part will write a part of the data and returns the result MultipartPart.

MultipartWriter will call this API and stores the result in order.

• part_number is the index of the part, starting from 0.

fn complete_part( &self, upload_id: &str, parts: &[MultipartPart], ) -> impl Future<Output = Result<Metadata>> + MaybeSend

complete_part will complete the multipart upload to build the final file.

fn abort_part( &self, upload_id: &str, ) -> impl Future<Output = Result<()>> + MaybeSend

abort_part will cancel the multipart upload and purge all data.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors