Module opendal::docs::upgrade

Expand description

Upgrade and migrate procedures while OpenDAL meets breaking changes.

Upgrade to v0.28

In v0.28, we introduced Query Based Metadata. Users can query cached metadata with ObjectMetakey to make sure that OpenDAL always makes the best decision.

- pub async fn metadata(&self) -> Result<ObjectMetadata>;
+ pub async fn metadata(
+        &self,
+        flags: impl Into<FlagSet<ObjectMetakey>>,
+    ) -> Result<Arc<ObjectMetadata>>;

Please visit Object::metadata()’s example for more details.

Upgrade to v0.27

In v0.27, we refactored our list related logic and added scan support. So make Pager and BlockingPager associated types in Accessor too!

pub trait Accessor: Send + Sync + Debug + Unpin + 'static {
    type Reader: output::Read;
    type BlockingReader: output::BlockingRead;
+    type Pager: output::Page;
+    type BlockingPager: output::BlockingPage;
}

User defined layers

Due to this change, all layers implementation should be changed. If there is not changed over pager, they can by changed like the following:

impl<A: Accessor> LayeredAccessor for MyAccessor<A> {
    type Inner = A;
    type Reader = MyReader<A::Reader>;
    type BlockingReader = MyReader<A::BlockingReader>;
+    type Pager = A::Pager;
+    type BlockingPager = A::BlockingPager;

+    async fn list(&self, path: &str, args: OpList) -> Result<(RpList, Self::Pager)> {
+        self.inner.list(path, args).await
+    }

+    async fn scan(&self, path: &str, args: OpScan) -> Result<(RpScan, Self::Pager)> {
+        self.inner.scan(path, args).await
+    }

+    fn blocking_list(&self, path: &str, args: OpList) -> Result<(RpList, Self::BlockingPager)> {
+        self.inner.blocking_list(path, args)
+    }

+    fn blocking_scan(&self, path: &str, args: OpScan) -> Result<(RpScan, Self::BlockingPager)> {
+        self.inner.blocking_scan(path, args)
+    }
}

Usage of ops

To reduce the understanding overhead, we move all OpXxx into opendal::ops now. User may need to change:

- use opendal::OpWrite;
+ use opendal::ops::OpWrite;

Usage of RetryLayer

backon is the implementation detail of our RetryLayer, so we hide it from our public API. Users of RetryLayer need to change the code like:

- RetryLayer::new(backon::ExponentialBackoff::default())
+ RetryLayer::new()

Upgrade to v0.26

In v0.26 we have replaced all internal dynamic dispatch usage with static dispatch. With this change, we can ensure that all operations performed inside OpenDAL are zero cost.

Due to this change, we have to refactor the logic of Operator’s init logic. In v0.26, we added opendal::Builder trait and opendal::OperatorBuilder. For the first glance, the only change to existing code will be like:

- let op = Operator::new(builder.build()?);
+ let op = Operator::new(builder.build()?).finish();

By adding a finish() call, we will erase all generic types so that Operator can still be easily to used everywhere as before.

Accessor

In v0.26, Accessor has been changed into trait with associated types.

All services need to declare the types returned as Reader or BlockingReader:

pub trait Accessor: Send + Sync + Debug + Unpin + 'static {
    type Reader: output::Read;
    type BlockingReader: output::BlockingRead;
}

If your service doesn’t support read or blocking_read, we can use () to represent an dummy reader:

impl Accessor for MyDummyAccessor {
    type Reader = ();
    type BlockingReader = ();
}

Layer

As described before, OpenDAL prefer to use static dispatch. Layers are required to implement the new Layer and LayeredAccessor trait:

pub trait Layer<A: Accessor> {
    type LayeredAccessor: Accessor;

    fn layer(&self, inner: A) -> Self::LayeredAccessor;
}

#[async_trait]
pub trait LayeredAccessor: Send + Sync + Debug + Unpin + 'static {
    type Inner: Accessor;
    type Reader: output::Read;
    type BlockingReader: output::BlockingRead;
}

LayeredAccessor is a wrapper of Accessor with the typed Innder. All methods that not implemented will be forward to inner instead.

Builder

Since v0.26, we implement opendal::Builder for all services, and services’ mod will not be exported.

- use opendal::services::s3::Builder;
+ use opendal::services::S3;

Conclusion

Sorry again for the big changes in this release. It’s a big step for OpenDAL to work in more critical systems.

Upgrade to v0.25

In v0.25, we bring the same feature sets from ObjectReader to BlockingObjectReader.

Due to this change, all code that depends on BlockingBytesReader should be refactored.

BlockingBytesReader => input::BlockingReader
BlockingOutputBytesReader => output::BlockingReader

Most changes only happen inside. Users not using opendal::raw::* will not be affected.

Apart from this change, we refactored s3 credential loading logic. After this change, we can disable the config load instead of the credential methods.

builder.disable_credential_loader => builder.disable_config_load

Upgrade to v0.24

In v0.24, we made a big refactor on our internal IO-related traits. In this version, we split our IO traits into input and output versions:

Take Reader as an example:

input::Reader is the user input reader, which only requires futures::AsyncRead + Send.

output::Reader is the reader returned by OpenDAL, which implements futures::AsyncRead, futures::AsyncSeek, and futures::Stream<Item=io::Result<Bytes>>. Besides, output::Reader also implements Send + Sync, which makes it useful for users.

Due to this change, all code that depends on BytesReader should be refactored.

BytesReader => input::Reader
OutputBytesReader => output::Reader

Thanks to the change of IO trait split, we make ObjectReader implements all needed traits:

futures::AsyncRead
futures::AsyncSeek
futures::Stream<Item=io::Result<Bytes>>

Thus, we removed the seekable_reader API. They can be replaced by range_reader:

o.seekable_reader => o.range_reader

Most changes only happen inside. Users not using opendal::raw::* will not be affected.

Sorry for the inconvenience. I think those changes are required and make OpenDAL better! Welcome any comments at Discussion.

Upgrade to v0.21

v0.21 is an internal refactor version of OpenDAL. In this version, we refactored our error handling and our Accessor APIs. Thanks to those internal changes, we added an object-level metadata cache, making it nearly zero cost to reuse existing metadata continuously.

Let’s start with our errors.

Error Handling

As described in RFC-0977: Refactor Error, we refactor opendal error by a new error called opendal::Error.

This change will affect all APIs that are used to return io::Error.

To migrate this, please replace std::io::Error with opendal::Error:

- use std::io::Result;
+ use opendal::Result;

And the following error kinds should be updated:

std::io::ErrorKind::NotFound => opendal::ErrorKind::ObjectNotFound
std::io::ErrorKind::PermissionDenied => opendal::ErrorKind::ObjectPermissionDenied

And since v0.21, we will return errors ObjectIsADirectory and ObjectNotADirectory instead of anyhow::Error.

Accessor API

In v0.21, we refactor the whole Accessor’s API:

- async fn write(&self, path: &str, args: OpWrite, r: BytesReader) -> Result<u64>
+ async fn write(&self, path: &str, args: OpWrite, r: BytesReader) -> Result<RpWrite>

Since v0.21, we will return a reply struct for different operations called RpWrite instead of an exact type. We can split OpenDAL’s public API and raw API with this change.

ObjectList and Page

Since v0.21, Accessor will return Pager for List:

- async fn list(&self, path: &str, args: OpList) -> Result<ObjectStreamer>
+ async fn list(&self, path: &str, args: OpList) -> Result<(RpList, output::Pager)>

And Object will return an ObjectLister which is built upon Page:

pub async fn list(&self) -> Result<ObjectLister> { ... }

ObjectLister can be used as an object stream as before. It also provides the function next_page to get the underlying pages directly:

impl ObjectLister {
    pub async fn next_page(&mut self) -> Result<Option<Vec<Object>>>;
}

Code Layout

Since v0.21, we have categorized all APIs into public and raw.

Public APIs are exposed under opendal::Xxx; they are user-face APIs that are easy to use and understand.

Raw APIs are exposed under opendal::raw::Xxx; they are implementation details for underlying services and layers.

Please replace all usage of opendal::io_util::* and opendal::http_util::* to opendal::raw::* instead.

With this change, new users of OpenDAL maybe be it easier to get started.

Summary

Sorry for introducing too much breaking change in a single version. This version can be a solid version for preparing OpenDAL v1.0.

Upgrade to v0.20

v0.20 is a big release that we introduce a lot of performance related changes.

To make the best of information from read operation, we propose and implemented RFC-0926: Object Reader. By this RFC, we can fetch content length from ObjectReader now!

pub struct ObjectReader {
    inner: BytesReader
    meta: ObjectMetadata,
}

impl ObjectReader {
    pub fn content_length(&self) -> u64 {}
    pub fn last_modified(&self) -> Option<OffsetDateTime> {}
    pub fn etag(&self) -> Option<String> {}
}

To make this happen, we changed our Accessor API:

- async fn read(&self, path: &str, args: OpRead) -> Result<BytesReader> {}
+ async fn read(&self, path: &str, args: OpRead) -> Result<ObjectReader> {}

All layers should be updated to meet this change. Also, it’s required to return content_length while building ObjectReader. Please make sure the returning ObjectMetadata is used correctly.

Upgrade to v0.19

OpenDAL deprecate some features:

serde: We will enable it by default.
layers-retry: We will enable retry support by default.
layers-metadata-cache: We will enable it by default.

Deprecated types like DirEntry has been removed.

Upgrade to v0.18

OpenDAL v0.18 introduces the following breaking changes:

Deprecated feature flag services-http has been removed.
All DirXxx items have been renamed to ObjectXxx to make them more consistent.
- DirEntry -> Entry
- DirStream -> ObjectStream
- DirStreamer -> ObjectStream
- DirIterate -> ObjectIterate
- DirIterator -> ObjectIterator

Besides, we also make a big change to our Entry API. Since v0.18, we can fully reuse the metadata that fetched during list. Take entry.content_length() for example:

If content_length is already known, we will return directly.
If not, we will check if the object entry is complete:
- If complete, the entry already fetched all metadata that it could have, return directly.
- If not, we will send a stat call to get the metadata and refresh our cache.

This change means:

All API like content_length will be changed into async functions.
metadata and blocking_metadata will not return errors anymore.
To retrieve the latest meta, please use entry.into_object().metadata() instead.

Upgrade to v0.17

OpenDAL v0.17 refactor the Accessor to make space for future features.

We move path String out of the OpXxx to function args so that we don’t need to clone twice.

- async fn read(&self, args: OpRead) -> Result<BytesReader>
+ async fn read(&self, path: &str, args: OpRead) -> Result<BytesReader>

For more information about this change, please refer to RFC-0661: Path In Accessor.

And since OpenDAL v0.17, we will use rustls as default tls engine for our underlying http client. Since this release, we will not depend on openssl anymore.

Upgrade to v0.16

OpenDAL v0.16 refactor the internal implementation of http service. Since v0.16, http service can be used directly without enabling services-http feature. Accompany by these changes, http service has the following breaking changes:

services-http feature has been deprecated. Enabling services-http is a no-op now.
http service is read only services and can’t be used to list or write.

OpenDAL introduces a new layer ImmutableIndexLayer that can add list capability for services:

use opendal::layers::ImmutableIndexLayer;
use opendal::Operator;
use opendal::Scheme;

async fn main() {
    let mut iil = ImmutableIndexLayer::default();

    for i in ["file", "dir/", "dir/file", "dir_without_prefix/file"] {
        iil.insert(i.to_string())
    }

    let op = Operator::from_env(Scheme::Http)?.layer(iil);
}

For more information about this change, please refer to RFC-0627: Split Capabilities.

Upgrade to v0.14

OpenDAL v0.14 removed all deprecated APIs in previous versions, including:

Operator::with_backoff in v0.13
All services Builder::finish() in v0.12
All services Backend::build() in v0.12

Please visit related version’s upgrade guide for migration.

And in OpenDAL v0.14, we introduce a break change for write operations.

pub trait Accessor {
    - async fn write(&self, args: &OpWrite) -> Result<BytesWriter> {}
    + async fn write(&self, args: &OpWrite, r: BytesReader) -> Result<u64> {}
}

The following APIs have affected by this change:

Object::write now accept impl Into<Vec<u8>> instead of AsRef<&[u8]>
Object::writer has been removed.
Object::write_from has been added to support write from a reader.
All layers should be refactored to adapt new Accessor trait.

For more information about this change, please refer to RFC-0554: Write Refactor.

Upgrade to v0.13

OpenDAL deprecate Operator::with_backoff since v0.13.

Please use RetryLayer instead:

use anyhow::Result;
use backon::ExponentialBackoff;
use opendal::layers::RetryLayer;
use opendal::Operator;
use opendal::Scheme;

let _ = Operator::from_env(Scheme::Fs)
    .expect("must init")
    .layer(RetryLayer::new(ExponentialBackoff::default()));

Upgrade to v0.12

OpenDAL introduces breaking changes for services initiation.

Since v0.12, Operator::new will accept impl Accessor + 'static instead of Arc<dyn Accessor>:

impl Operator {
    pub fn new(accessor: impl Accessor + 'static) -> Self { .. }
}

Every service’s Builder now have a build() API which can be run without async:

let mut builder = fs::Builder::default();
let op: Operator = Operator::new(builder.build()?);

Along with these changes, Operator::from_iter and Operator::from_env now is a blocking API too.

For more information about this change, please refer to RFC-0501: New Builder.

The following APIs have been deprecated:

All services Builder::finish() (replaced by Builder::build())
All services Backend::build() (replace by Builder::default())

The following APIs have been removed:

public struct Metadata (deprecated in v0.8, replaced by ObjectMetadata)

Upgrade to v0.8

OpenDAL introduces a breaking change of list related operations in v0.8.

Since v0.8, list will return DirStreamer instead:

pub trait Accessor: Send + Sync + Debug {
    async fn list(&self, args: &OpList) -> Result<DirStreamer> {}
}

DirStreamer streams DirEntry which carries ObjectMode, so that we don’t need an extra call to get object mode:

impl DirEntry {
    pub fn mode(&self) -> ObjectMode {
        self.mode
    }
}

And DirEntry can be converted into Object without overhead:

let o: Object = de.into()

Since v0.8, opendal::Metadata has been deprecated by opendal::ObjectMetadata.

Upgrade to v0.7

OpenDAL introduces a breaking change of decompress_read related in v0.7.

Since v0.7, decompress_read and decompress_reader will return Ok(None) while OpenDAL can’t detect the correct compress algorithm.

impl Object {
    pub async fn decompress_read(&self) -> Result<Option<Vec<u8>>> {}
    pub async fn decompress_reader(&self) -> Result<Option<impl BytesRead>> {}
}

So users should match and check the None case:

let bs = o.decompress_read().await?.expect("must have valid compress algorithm");

Upgrade to v0.4

OpenDAL introduces many breaking changes in v0.4.

Object::reader() is not `AsyncSeek` anymore

Since v0.4, Object::reader() will return impl BytesRead instead of Reader that implements AsyncRead and AsyncSeek. Users who want AsyncSeek please wrapped with opendal::io_util::seekable_read:

use opendal::io_util::seekable_read;

let o = op.object("test");
let mut r = seekable_read(&o, 10..);
r.seek(SeekFrom::Current(10)).await?;
let mut bs = vec![0;10];
r.read(&mut bs).await?;

Use RangeBounds instead

Since v0.4, the following APIs will be removed.

Object::limited_reader(size: u64)
Object::offset_reader(offset: u64)
Object::range_reader(offset: u64, size: u64)

Instead, OpenDAL is providing a more general range_reader powered by RangeBounds:

pub async fn range_reader(&self, range: impl RangeBounds<u64>) -> Result<impl BytesRead>

Users can use their familiar rust range syntax:

let r = o.range_reader(1024..2048).await?;

Return io::Result instead

Since v0.4, all functions in OpenDAL will return std::io::Result instead.

Please check via std::io::ErrorKind directly:

use std::io::ErrorKind;

if let Err(e) = op.object("test_file").metadata().await {
    if e.kind() == ErrorKind::NotFound {
        println!("object not exist")
    }
}

Removing Credential

Since v0.4, Credential has been removed, please use the API provided by Builder directly.

builder.access_key_id("access_key_id");
builder.secret_access_key("secret_access_key");

Write returns `BytesWriter` instead

Since v0.4, Accessor::write will return a BytesWriter instead accepting a BoxedAsyncReader.

Along with this change, the old Writer has been replaced by a new set of write functions:

pub async fn write(&self, bs: impl AsRef<[u8]>) -> Result<()> {}
pub async fn writer(&self, size: u64) -> Result<impl BytesWrite> {}

Users can write into an object more easily:

let _ = op.object("path/to/file").write("Hello, World!").await?;

`io_util` replaces `readers`

Since v0.4, mod io_util will replace readers. In io_utils, OpenDAL provides helpful functions like:

into_reader: Convert BytesStream into BytesRead
into_sink: Convert BytesWrite into BytesSink
into_stream: Convert BytesRead into BytesStream
into_writer: Convert BytesSink into BytesWrite
observe_read: Add callback for BytesReader
observe_write: Add callback for BytesWrite

New type alias

For better naming, types that OpenDAL returns have been renamed:

AsyncRead + Unpin + Send => BytesRead
BoxedAsyncReader => BytesReader
AsyncWrite + Unpin + Send => BytesWrite
BoxedAsyncWriter => BytesWriter
ObjectStream => ObjectStreamer