Unverified Commit 75fc85f6 authored by ysaito1001's avatar ysaito1001 Committed by GitHub
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Remove `futures_core::stream::Stream` from `aws-smithy-async` (#2978) 

## Motivation and Context
Removes `futures_core::stream::Stream` from the `aws-smithy-async`
crate.

## Description
This PR is part of our ongoing effort,
https://github.com/awslabs/smithy-rs/issues/2413. We remove the
`futures_core::stream::Stream` trait from the public API in the
`aws-smithy-async` crate. While doing so, we compensate
- `FnStream` by providing the explicit `.next` and `.collect` methods to
let the previously working code continue working.
- `TryFlatMap` by making it return a new-type wrapper `PaginationStream`
to hide `FnStream` from those who use paginators.

With this change, the latest canary no longer uses
`tokio_stream::StreamExt`, since the paginator does not work in terms of
the `Stream` trait. Furthermore, `aws-sdk-rust` has been more than [3
releases since
release-2023-01-26](https://github.com/awslabs/aws-sdk-rust/releases),
so the module `release-2023-01-26` has been removed from
`canary-lambda`.

## Testing
No new tests added, but made sure the existing tests keep working with
the change.

## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the
smithy-rs codegen or runtime crates
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the AWS
SDK, generated SDK code, or SDK runtime crates

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._
parent 673e385c

CHANGELOG.next.toml

+12 −0
Original line number Diff line number Diff line
@@ -183,3 +183,15 @@ message = "Produce better docs when items are marked @required" 
references = ["smithy-rs#2996"]

meta = { "breaking" = false, "tada" = false, "bug" = false, "target" = "client" }

author = "rcoh"



[[aws-sdk-rust]]

message = "The `futures_core::stream::Stream` trait has been removed from public API. It should not affect usual SDK use cases. If your code uses paginators, you do not need to use the `Stream` trait or its exntension traits, but only the `next`, `try_next`, `collect`, and `try_collect` methods are supported on `PaginationStream`. Other stream operations that were previously available through the trait or its extension traits can be added later in a backward compatible manner. Finally, `fn_stream` has been moved to be a child module of `pagination_stream`."

references = ["smithy-rs#2978"]

meta = { "breaking" = true, "tada" = false, "bug" = false }

author = "ysaito1001"



[[smithy-rs]]

message = "The `futures_core::stream::Stream` trait has been removed from public API. `FnStream` only supports `next`, `try_next`, `collect`, and `try_collect` methods. [`TryFlatMap::flat_map`](https://docs.rs/aws-smithy-async/latest/aws_smithy_async/future/pagination_stream/struct.TryFlatMap.html#method.flat_map) returns [`PaginationStream`](https://docs.rs/aws-smithy-async/latest/aws_smithy_async/future/pagination_stream/struct.PaginationStream.html), which should be preferred to `FnStream` at an interface level. Other stream operations that were previously available through the trait or its extension traits can be added later in a backward compatible manner. Finally, `fn_stream` has been moved to be a child module of `pagination_stream`."

references = ["smithy-rs#2978"]

meta = { "breaking" = true, "tada" = false, "bug" = false, "target" = "client" }

author = "ysaito1001"

aws/sdk/integration-tests/dynamodb/tests/paginators.rs

+0 −2
Original line number Diff line number Diff line
@@ -6,8 +6,6 @@ 
use std::collections::HashMap;

use std::iter::FromIterator;



use tokio_stream::StreamExt;



use aws_credential_types::Credentials;

use aws_sdk_dynamodb::types::AttributeValue;

use aws_sdk_dynamodb::{Client, Config};

aws/sdk/integration-tests/ec2/tests/paginators.rs

+0 −2
Original line number Diff line number Diff line
@@ -3,8 +3,6 @@ 
 * SPDX-License-Identifier: Apache-2.0

 */



use tokio_stream::StreamExt;



use aws_sdk_ec2::{config::Credentials, config::Region, types::InstanceType, Client, Config};

use aws_smithy_client::http_connector::HttpConnector;

use aws_smithy_client::test_connection::TestConnection;

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/PaginatorGenerator.kt

+11 −9
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ class PaginatorGenerator private constructor( 
        "HttpResponse" to RuntimeType.smithyRuntimeApi(runtimeConfig).resolve("client::orchestrator::HttpResponse"),

        "SdkError" to RuntimeType.sdkError(runtimeConfig),

        "client" to RuntimeType.smithyClient(runtimeConfig),

        "fn_stream" to RuntimeType.smithyAsync(runtimeConfig).resolve("future::fn_stream"),

        "pagination_stream" to RuntimeType.smithyAsync(runtimeConfig).resolve("future::pagination_stream"),



        // External Types

        "Stream" to RuntimeType.TokioStream.resolve("Stream"),
@@ -141,13 +141,14 @@ class PaginatorGenerator private constructor( 


                /// Create the pagination stream

                ///

                /// _Note:_ No requests will be dispatched until the stream is used (eg. with [`.next().await`](tokio_stream::StreamExt::next)).

                pub fn send(self) -> impl #{Stream}<Item = #{item_type}> + #{Unpin} {

                /// _Note:_ No requests will be dispatched until the stream is used

                /// (e.g. with the [`.next().await`](aws_smithy_async::future::pagination_stream::PaginationStream::next) method).

                pub fn send(self) -> #{pagination_stream}::PaginationStream<#{item_type}> {

                    // Move individual fields out of self for the borrow checker

                    let builder = self.builder;

                    let handle = self.handle;

                    #{runtime_plugin_init}

                    #{fn_stream}::FnStream::new(move |tx| #{Box}::pin(async move {

                    #{pagination_stream}::PaginationStream::new(#{pagination_stream}::fn_stream::FnStream::new(move |tx| #{Box}::pin(async move {

                        // Build the input for the first time. If required fields are missing, this is where we'll produce an early error.

                        let mut input = match builder.build().map_err(#{SdkError}::construction_failure) {

                            #{Ok}(input) => input,
@@ -177,7 +178,7 @@ class PaginatorGenerator private constructor( 
                                return

                            }

                        }

                    }))

                    })))

                }

            }

            """,
@@ -257,11 +258,12 @@ class PaginatorGenerator private constructor( 
                impl ${paginatorName}Items {

                    /// Create the pagination stream

                    ///

                    /// _Note: No requests will be dispatched until the stream is used (eg. with [`.next().await`](tokio_stream::StreamExt::next))._

                    /// _Note_: No requests will be dispatched until the stream is used

                    /// (e.g. with the [`.next().await`](aws_smithy_async::future::pagination_stream::PaginationStream::next) method).

                    ///

                    /// To read the entirety of the paginator, use [`.collect::<Result<Vec<_>, _>()`](tokio_stream::StreamExt::collect).

                    pub fn send(self) -> impl #{Stream}<Item = #{item_type}> + #{Unpin} {

                        #{fn_stream}::TryFlatMap::new(self.0.send()).flat_map(|page| #{extract_items}(page).unwrap_or_default().into_iter())

                    /// To read the entirety of the paginator, use [`.collect::<Result<Vec<_>, _>()`](aws_smithy_async::future::pagination_stream::PaginationStream::collect).

                    pub fn send(self) -> #{pagination_stream}::PaginationStream<#{item_type}> {

                        #{pagination_stream}::TryFlatMap::new(self.0.send()).flat_map(|page| #{extract_items}(page).unwrap_or_default().into_iter())

                    }

                }

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/client/FluentClientGenerator.kt

+1 −1
Original line number Diff line number Diff line
@@ -433,7 +433,7 @@ class FluentClientGenerator( 
                        """

                        /// Create a paginator for this request

                        ///

                        /// Paginators are used by calling [`send().await`](#{Paginator}::send) which returns a `Stream`.

                        /// Paginators are used by calling [`send().await`](#{Paginator}::send) which returns a [`PaginationStream`](aws_smithy_async::future::pagination_stream::PaginationStream).

                        pub fn into_paginator(self) -> #{Paginator} {

                            #{Paginator}::new(self.handle, self.inner)

                        }