在 catch_unwind 期间将回溯转换为字符串
Transform backtrace to string during catch_unwind
我正在用 Rust 编写跨平台 (Linux/iOS/Android) 库。万一我的库出现恐慌，我希望应用程序继续正常工作而不是崩溃。为此，我使用 catch_unwind;它的结果包含恐慌信息并且没有包含足够的关于问题根源的信息，这里有一段代码解释了我在做什么：
fn calculate(json: &str) -> String {
unimplemented!()
}
#[no_mangle]
pub fn rust_calculation(json: &str) -> String {
let r = std::panic::catch_unwind(||{
// rust calculation
let calc: String = calculate(json).into();
calc
});
let r_str = match r {
Ok(v) => v,
Err(e) => {
let panic_information = match e.downcast::<String>() {
Ok(v) => *v,
_ => "Unknown Source of Error".to_owned()
};
panic_information
}
};
return r_str;
}
fn main() {
println!("{}", rust_calculation("test"));
}
如果发生错误，返回的消息是不够的，有时只包含消息
Unknown Source of Error
我想将回溯发送到调用源，以便它可以记录它，然后我们可以在之后调试 Rust 库。我该怎么做？
some times it countains the message:
Unknown Source of Error
这可能是因为e不仅可以是String，还可以是&str（好吧，基本上可以是任何类型，但这两个是最常见的, 你只能在使用 panic_any() 时得到其他类型)。当在 catch_unwind() 中调用 panic!() 时，如果您使用参数 panic!，您只会得到 String，否则，恐慌消息是 &str（如不需要分配 String).
I want to send the backtrace to the calling source so that he can log it and then we can debug the rust library afterwards, how can I do that ?
夜间 Rust 的解决方案
在 nightly Rust 上，您可以通过 std::backtrace::Backtrace:
在 panic 处理程序中生成回溯
#![feature(backtrace)]
use lazy_static::lazy_static;
use std::sync::{Arc, Mutex};
// on panic, save the backtrace here (as string)
lazy_static! {
static ref BACKTRACE: Arc<Mutex<Option<String>>> = Arc::new(Mutex::new(None));
}
#[no_mangle]
pub fn rust_calculation(json: &str) -> String {
let r = std::panic::catch_unwind(||{
panic!("Panic");
});
let r_str = match r {
Ok(v) => v,
Err(e) => {
let panic_information = match e.downcast::<String>() {
Ok(v) => *v,
Err(e) => match e.downcast::<&str>() {
Ok(v) => v.to_string(),
_ => "Unknown Source of Error".to_owned()
}
};
format!("{}\nBacktrace:\n{}", panic_information, BACKTRACE.lock().unwrap().take().unwrap_or("<Backtrace not found>".to_string()))
}
};
return r_str;
}
fn panic_hook(_: &std::panic::PanicInfo) {
*BACKTRACE.lock().unwrap() = Some(std::backtrace::Backtrace::force_capture().to_string());
}
fn main() {
std::panic::set_hook(Box::new(panic_hook));
println!("{}", rust_calculation(""));
}
输出：
Panic
Backtrace:
0: playground::panic_hook
at ./src/main.rs:32:39
1: core::ops::function::Fn::call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/core/src/ops/function.rs:70:5
2: std::panicking::rust_panic_with_hook
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:626:17
3: std::panicking::begin_panic::{{closure}}
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:542:9
4: std::sys_common::backtrace::__rust_end_short_backtrace
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/sys_common/backtrace.rs:141:18
5: std::panicking::begin_panic
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:541:12
6: playground::rust_calculation::{{closure}}
at ./src/main.rs:13:9
7: std::panicking::try::do_call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:401:40
8: __rust_try
9: std::panicking::try
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:365:19
10: std::panic::catch_unwind
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panic.rs:434:14
11: rust_calculation
at ./src/main.rs:12:13
12: playground::main
at ./src/main.rs:37:20
13: core::ops::function::FnOnce::call_once
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/core/src/ops/function.rs:227:5
14: std::sys_common::backtrace::__rust_begin_short_backtrace
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/sys_common/backtrace.rs:125:18
15: std::rt::lang_start::{{closure}}
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:63:18
16: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/core/src/ops/function.rs:259:13
17: std::panicking::try::do_call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:401:40
18: std::panicking::try
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:365:19
19: std::panic::catch_unwind
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panic.rs:434:14
20: std::rt::lang_start_internal::{{closure}}
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:45:48
21: std::panicking::try::do_call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:401:40
22: std::panicking::try
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:365:19
23: std::panic::catch_unwind
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panic.rs:434:14
24: std::rt::lang_start_internal
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:45:20
25: std::rt::lang_start
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:62:5
26: main
27: __libc_start_main
28: _start
请注意，由于 Rust 的内部恐慌处理代码，此回溯在调用 panic! 之后包含一些额外的帧。
具有依赖关系的解决方案
如果你不使用 nightly Rust，但愿意使用额外的依赖项，你可以对 backtrace crate 做同样的事情（感谢 @BashirAbdelwahed 提醒我注意这一点）：
use lazy_static::lazy_static;
use std::sync::{Arc, Mutex};
// on panic, save the backtrace here (as string)
lazy_static! {
static ref BACKTRACE: Arc<Mutex<Option<String>>> = Arc::new(Mutex::new(None));
}
#[no_mangle]
pub fn rust_calculation(json: &str) -> String {
let r = std::panic::catch_unwind(||{
panic!("Panic");
});
let r_str = match r {
Ok(v) => v,
Err(e) => {
let panic_information = match e.downcast::<String>() {
Ok(v) => *v,
Err(e) => match e.downcast::<&str>() {
Ok(v) => v.to_string(),
_ => "Unknown Source of Error".to_owned()
}
};
format!("{}\nBacktrace:\n{}", panic_information, BACKTRACE.lock().unwrap().take().unwrap_or("<Backtrace not found>".to_string()))
}
};
return r_str;
}
fn panic_hook(_: &std::panic::PanicInfo) {
*BACKTRACE.lock().unwrap() = Some(format!("{:?}", backtrace::Backtrace::new()));
}
fn main() {
std::panic::set_hook(Box::new(panic_hook));
println!("{}", rust_calculation(""));
}
输出：
Panic
Backtrace:
0: playground::panic_hook
at src/main.rs:31:55
1: core::ops::function::Fn::call
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/ops/function.rs:70:5
2: std::panicking::rust_panic_with_hook
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:595:17
3: std::panicking::begin_panic::{{closure}}
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:520:9
4: std::sys_common::backtrace::__rust_end_short_backtrace
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/sys_common/backtrace.rs:141:18
5: std::panicking::begin_panic
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:519:12
6: playground::rust_calculation::{{closure}}
at src/main.rs:12:9
7: std::panicking::try::do_call
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:379:40
8: __rust_try
9: std::panicking::try
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:343:19
10: std::panic::catch_unwind
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panic.rs:431:14
11: rust_calculation
at src/main.rs:11:13
12: playground::main
at src/main.rs:36:20
13: core::ops::function::FnOnce::call_once
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/ops/function.rs:227:5
14: std::sys_common::backtrace::__rust_begin_short_backtrace
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/sys_common/backtrace.rs:125:18
15: std::rt::lang_start::{{closure}}
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/rt.rs:49:18
16: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/ops/function.rs:259:13
std::panicking::try::do_call
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:379:40
std::panicking::try
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:343:19
std::panic::catch_unwind
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panic.rs:431:14
std::rt::lang_start_internal
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/rt.rs:34:21
17: std::rt::lang_start
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/rt.rs:48:5
18: main
19: __libc_start_main
20: _start
我正在用 Rust 编写跨平台 (Linux/iOS/Android) 库。万一我的库出现恐慌，我希望应用程序继续正常工作而不是崩溃。为此，我使用 catch_unwind;它的结果包含恐慌信息并且没有包含足够的关于问题根源的信息，这里有一段代码解释了我在做什么：
fn calculate(json: &str) -> String {
unimplemented!()
}
#[no_mangle]
pub fn rust_calculation(json: &str) -> String {
let r = std::panic::catch_unwind(||{
// rust calculation
let calc: String = calculate(json).into();
calc
});
let r_str = match r {
Ok(v) => v,
Err(e) => {
let panic_information = match e.downcast::<String>() {
Ok(v) => *v,
_ => "Unknown Source of Error".to_owned()
};
panic_information
}
};
return r_str;
}
fn main() {
println!("{}", rust_calculation("test"));
}
如果发生错误，返回的消息是不够的，有时只包含消息
Unknown Source of Error
我想将回溯发送到调用源，以便它可以记录它，然后我们可以在之后调试 Rust 库。我该怎么做？
some times it countains the message:
Unknown Source of Error
这可能是因为e不仅可以是String，还可以是&str（好吧，基本上可以是任何类型，但这两个是最常见的, 你只能在使用 panic_any() 时得到其他类型)。当在 catch_unwind() 中调用 panic!() 时，如果您使用参数 panic!，您只会得到 String，否则，恐慌消息是 &str（如不需要分配 String).
I want to send the backtrace to the calling source so that he can log it and then we can debug the rust library afterwards, how can I do that ?
夜间 Rust 的解决方案
在 nightly Rust 上，您可以通过 std::backtrace::Backtrace:
#![feature(backtrace)]
use lazy_static::lazy_static;
use std::sync::{Arc, Mutex};
// on panic, save the backtrace here (as string)
lazy_static! {
static ref BACKTRACE: Arc<Mutex<Option<String>>> = Arc::new(Mutex::new(None));
}
#[no_mangle]
pub fn rust_calculation(json: &str) -> String {
let r = std::panic::catch_unwind(||{
panic!("Panic");
});
let r_str = match r {
Ok(v) => v,
Err(e) => {
let panic_information = match e.downcast::<String>() {
Ok(v) => *v,
Err(e) => match e.downcast::<&str>() {
Ok(v) => v.to_string(),
_ => "Unknown Source of Error".to_owned()
}
};
format!("{}\nBacktrace:\n{}", panic_information, BACKTRACE.lock().unwrap().take().unwrap_or("<Backtrace not found>".to_string()))
}
};
return r_str;
}
fn panic_hook(_: &std::panic::PanicInfo) {
*BACKTRACE.lock().unwrap() = Some(std::backtrace::Backtrace::force_capture().to_string());
}
fn main() {
std::panic::set_hook(Box::new(panic_hook));
println!("{}", rust_calculation(""));
}
输出：
Panic
Backtrace:
0: playground::panic_hook
at ./src/main.rs:32:39
1: core::ops::function::Fn::call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/core/src/ops/function.rs:70:5
2: std::panicking::rust_panic_with_hook
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:626:17
3: std::panicking::begin_panic::{{closure}}
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:542:9
4: std::sys_common::backtrace::__rust_end_short_backtrace
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/sys_common/backtrace.rs:141:18
5: std::panicking::begin_panic
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:541:12
6: playground::rust_calculation::{{closure}}
at ./src/main.rs:13:9
7: std::panicking::try::do_call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:401:40
8: __rust_try
9: std::panicking::try
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:365:19
10: std::panic::catch_unwind
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panic.rs:434:14
11: rust_calculation
at ./src/main.rs:12:13
12: playground::main
at ./src/main.rs:37:20
13: core::ops::function::FnOnce::call_once
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/core/src/ops/function.rs:227:5
14: std::sys_common::backtrace::__rust_begin_short_backtrace
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/sys_common/backtrace.rs:125:18
15: std::rt::lang_start::{{closure}}
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:63:18
16: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/core/src/ops/function.rs:259:13
17: std::panicking::try::do_call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:401:40
18: std::panicking::try
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:365:19
19: std::panic::catch_unwind
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panic.rs:434:14
20: std::rt::lang_start_internal::{{closure}}
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:45:48
21: std::panicking::try::do_call
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:401:40
22: std::panicking::try
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panicking.rs:365:19
23: std::panic::catch_unwind
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/panic.rs:434:14
24: std::rt::lang_start_internal
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:45:20
25: std::rt::lang_start
at /rustc/2faabf579323f5252329264cc53ba9ff803429a3/library/std/src/rt.rs:62:5
26: main
27: __libc_start_main
28: _start
请注意，由于 Rust 的内部恐慌处理代码，此回溯在调用 panic! 之后包含一些额外的帧。
具有依赖关系的解决方案
如果你不使用 nightly Rust，但愿意使用额外的依赖项，你可以对 backtrace crate 做同样的事情（感谢 @BashirAbdelwahed 提醒我注意这一点）：
use lazy_static::lazy_static;
use std::sync::{Arc, Mutex};
// on panic, save the backtrace here (as string)
lazy_static! {
static ref BACKTRACE: Arc<Mutex<Option<String>>> = Arc::new(Mutex::new(None));
}
#[no_mangle]
pub fn rust_calculation(json: &str) -> String {
let r = std::panic::catch_unwind(||{
panic!("Panic");
});
let r_str = match r {
Ok(v) => v,
Err(e) => {
let panic_information = match e.downcast::<String>() {
Ok(v) => *v,
Err(e) => match e.downcast::<&str>() {
Ok(v) => v.to_string(),
_ => "Unknown Source of Error".to_owned()
}
};
format!("{}\nBacktrace:\n{}", panic_information, BACKTRACE.lock().unwrap().take().unwrap_or("<Backtrace not found>".to_string()))
}
};
return r_str;
}
fn panic_hook(_: &std::panic::PanicInfo) {
*BACKTRACE.lock().unwrap() = Some(format!("{:?}", backtrace::Backtrace::new()));
}
fn main() {
std::panic::set_hook(Box::new(panic_hook));
println!("{}", rust_calculation(""));
}
输出：
Panic
Backtrace:
0: playground::panic_hook
at src/main.rs:31:55
1: core::ops::function::Fn::call
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/ops/function.rs:70:5
2: std::panicking::rust_panic_with_hook
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:595:17
3: std::panicking::begin_panic::{{closure}}
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:520:9
4: std::sys_common::backtrace::__rust_end_short_backtrace
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/sys_common/backtrace.rs:141:18
5: std::panicking::begin_panic
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:519:12
6: playground::rust_calculation::{{closure}}
at src/main.rs:12:9
7: std::panicking::try::do_call
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:379:40
8: __rust_try
9: std::panicking::try
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:343:19
10: std::panic::catch_unwind
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panic.rs:431:14
11: rust_calculation
at src/main.rs:11:13
12: playground::main
at src/main.rs:36:20
13: core::ops::function::FnOnce::call_once
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/ops/function.rs:227:5
14: std::sys_common::backtrace::__rust_begin_short_backtrace
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/sys_common/backtrace.rs:125:18
15: std::rt::lang_start::{{closure}}
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/rt.rs:49:18
16: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/core/src/ops/function.rs:259:13
std::panicking::try::do_call
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:379:40
std::panicking::try
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panicking.rs:343:19
std::panic::catch_unwind
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/panic.rs:431:14
std::rt::lang_start_internal
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/rt.rs:34:21
17: std::rt::lang_start
at /rustc/53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b/library/std/src/rt.rs:48:5
18: main
19: __libc_start_main
20: _start