Redis 在Rust中将同步闭包移植到异步闭包时的生存期问题

我目前正在尝试将一些使用crate和Redis事务的锈迹代码从同步代码移植到异步代码，并且遇到了一些问题（目前与生存期相关，但根本原因可能在端口的其他地方）

这两种情况下的代码都在

Cargo.toml

中使用以下依赖项：

[dependencies]
redis = "0.16"
tokio = { version = "0.2", features = ["full"] }

工作同步代码的最小示例如下所示：

使用redis:：{pipe，cmd，Pipeline，ToRedisArgs，RedisResult}；
fn main（）->RedisResult{
让client=redis:：client:：open（“redis://127.0.0.1/）展开（）；
让mut sync_conn=client.get_connection（）？；
让key=“foo”；
let（val，）：（u32，）=事务（&mut-sync_-conn，&key]，|conn，pipe |{
管道组件（图例1）
.ignore（）
.get（键）
.查询（康涅狄格州）
})?;
println！（“val:{}”，val）；
好（（））
}
fn交易<
C:redis:：连接类，
K:ToRedisArgs，
T
F:FnMut（&mut C，&mut管道）->RedisResult，
>(
con:&mut C，
键：&[K]，
func:F，
)->重新分配结果{
设mut func=func；
环路{
cmd（“WATCH”）.arg（键）.query（con）？；
如果让一些（响应）=func（con，pipe（）.atomic（））{
cmd（“UNWATCH”）.query（con）？；
返回Ok（响应）；
}
}
}

我尝试将此代码转换为异步代码，如下所示：

使用redis:：{AsyncCommands，pipe，cmd，Pipeline，ToRedisArgs，RedisResult，aio:：ConnectionLike}；
使用std:：future:：future；
#[tokio:：main]
异步fn main（）->RedisResult{
让client=redis:：client:：open（“redis://127.0.0.1/）展开（）；
让mut async_conn=client.get_async_connection（）.wait？；
让key=“foo”；
let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe|async{
管道组件（图例1）
.ignore（）
.get（键）
.query\u async（conn）.等待
}).等待？；
println！（“val:{}”，val）；
好（（））
}
发布异步fn异步\u事务<
C:连接式+发送，
K:ToRedisArgs，
T
F:FnMut（&mut C，&mut管道）->Fut，
未来,，
>(
con:&mut C，
键：&[K]，
func:F，
)->重新分配结果{
设mut func=func；
环路{
cmd（“WATCH”）.arg（键）。query_async（con）。wait？；
如果让一些（响应）=func（con，pipe（）.atomic（））。等待{
cmd（“UNWATCH”）.query_async（con.wait？；
返回Ok（响应）；
}
}
}

主要的变化是使用异步连接，使用async/wait和

query\u async

而不是

query

。另一个主要变化是传递给

async_transaction

的函数返回一个

Future

，而不是直接返回结果

然而，试图编译此文件会导致19个错误（它们大多是基于生命周期的）：

error[E0486]：表达式类型包含在表达式中无效的引用：`for fn（&mut redis:：aio:：Connection，&[&str][closure@src/main.rs:11:69:16:6键：&&str]）->impl std:：future:：future{async_事务：：}`
-->src/main.rs:11:26
|
11 | let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe | async{
|                          ^^^^^^^^^^^^^^^^^
|
注意：类型仅对11:69在主体上定义的匿名生存期#2有效
-->src/main.rs:11:69
|
11 | let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe | async{
|  _____________________________________________________________________^
12 | |管道组（图例1）
13 | |忽略（）
14 | |获取（关键）
15 | |.查询异步（conn）.等待
等待？；
| |_____^
错误[E0486]：表达式类型包含在表达式中无效的引用：`for fn（&mut redis:：aio:：Connection，&[&str][closure@src/main.rs:11:69:16:6键：&&str]）->impl std:：future:：future{async_事务：：}`
-->src/main.rs:11:26
|
11 | let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe | async{
|                          ^^^^^^^^^^^^^^^^^
|
注意：类型仅对11:69在主体上定义的匿名生存期#3有效
-->src/main.rs:11:69
|
11 | let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe | async{
|  _____________________________________________________________________^
12 | |管道组（图例1）
13 | |忽略（）
14 | |获取（关键）
15 | |.查询异步（conn）.等待
等待？；
| |_____^
错误[E0486]：表达式类型包含在表达式中无效的引用：`impl std:：future:：future`
-->src/main.rs:11:26
|
11 | let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe | async{
|  __________________________^
12 | |管道组（图例1）
13 | |忽略（）
14 | |获取（关键）
15 | |.查询异步（conn）.等待
等待？；
| |______^
|
注意：类型仅对11:69在主体上定义的匿名生存期#2有效
-->src/main.rs:11:69
|
11 | let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe | async{
|  _____________________________________________________________________^
12 | |管道组（图例1）
13 | |忽略（）
14 | |获取（关键）
15 | |.查询异步（conn）.等待
等待？；
| |_____^
错误[E0486]：表达式类型包含在表达式中无效的引用：`impl std:：future:：future`
-->src/main.rs:11:26
|
11 | let（val，）：（u32，）=async_事务（&mut async_conn，&key]，| conn，pipe | async{
|  __________________________^
12 | |管道组（图例1）
13 | |忽略（）
14 | |获取（关键）
15 | |.查询异步（conn）.等待
等待？；
| |______^
|
注：类型仅为v
error[E0486]: type of expression contains references that are not valid during the expression: `for<'_, '_> fn(&mut redis::aio::Connection, &[&str], [closure@src/main.rs:11:69: 16:6 key:&&str]) -> impl std::future::Future {async_transaction::<redis::aio::Connection, &str, (u32,), [closure@src/main.rs:11:69: 16:6 key:&&str], impl std::future::Future>}`
  --> src/main.rs:11:26
   |
11 |     let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |                          ^^^^^^^^^^^^^^^^^
   |
note: type is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `for<'_, '_> fn(&mut redis::aio::Connection, &[&str], [closure@src/main.rs:11:69: 16:6 key:&&str]) -> impl std::future::Future {async_transaction::<redis::aio::Connection, &str, (u32,), [closure@src/main.rs:11:69: 16:6 key:&&str], impl std::future::Future>}`
  --> src/main.rs:11:26
   |
11 |     let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |                          ^^^^^^^^^^^^^^^^^
   |
note: type is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `impl std::future::Future`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |______^
   |
note: type is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `impl std::future::Future`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |______^
   |
note: type is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `impl std::future::Future`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `impl std::future::Future`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `&mut impl std::future::Future`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `&mut impl std::future::Future`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `unsafe fn(&mut impl std::future::Future) -> std::pin::Pin<&mut impl std::future::Future> {std::pin::Pin::<&mut impl std::future::Future>::new_unchecked}`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `unsafe fn(&mut impl std::future::Future) -> std::pin::Pin<&mut impl std::future::Future> {std::pin::Pin::<&mut impl std::future::Future>::new_unchecked}`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `std::pin::Pin<&mut impl std::future::Future>`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `std::pin::Pin<&mut impl std::future::Future>`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `for<'r, 's, 't0> fn(std::pin::Pin<&'r mut impl std::future::Future>, &'s mut std::task::Context<'t0>) -> std::task::Poll<<impl std::future::Future as std::future::Future>::Output> {<impl std::future::Future as std::future::Future>::poll}`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0486]: type of expression contains references that are not valid during the expression: `for<'r, 's, 't0> fn(std::pin::Pin<&'r mut impl std::future::Future>, &'s mut std::task::Context<'t0>) -> std::task::Poll<<impl std::future::Future as std::future::Future>::Output> {<impl std::future::Future as std::future::Future>::poll}`
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: type is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0481]: lifetime of function argument does not outlive the function call
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: the function argument is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0481]: lifetime of function argument does not outlive the function call
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: the function argument is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0488]: lifetime of variable does not enclose its declaration
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: the variable is only valid for the anonymous lifetime #2 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0488]: lifetime of variable does not enclose its declaration
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: the variable is only valid for the anonymous lifetime #3 defined on the body at 11:69
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^

error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
   |
note: first, the lifetime cannot outlive the anonymous lifetime #3 defined on the body at 11:69...
  --> src/main.rs:11:69
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  _____________________________________________________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |_____^
note: ...so that the type `impl std::future::Future` is not borrowed for too long
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
note: but, the lifetime must be valid for the call at 11:26...
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^
note: ...so that argument is valid for the call
  --> src/main.rs:11:26
   |
11 |       let (val,): (u32,) = async_transaction(&mut async_conn, &[key], |conn, pipe| async {
   |  __________________________^
12 | |         pipe.set(key, 1)
13 | |             .ignore()
14 | |             .get(key)
15 | |             .query_async(conn).await
16 | |     }).await?;
   | |____________^

error: aborting due to 19 previous errors

For more information about this error, try `rustc --explain E0495`.
error: could not compile `redistest`.

To learn more, run the command again with --verbose.