fail-rs

Documentation

A fail point implementation for Rust.

Fail point is a code point that are used to inject errors by users at runtime. This crate is inspired by FreeBSD's failpoints.

Usage

First, add this to your Cargo.toml:

toml [dependencies] fail = "0.2"

Next, add the following code to your crate:

```rust

[macro_use]

extern crate fail; ```

Define the fail points:

``` fn functionreturntuple() { fail_point!("name1"); }

fn functionreturnothers() -> u64 { failpoint!("name2", |r| r.mapor(2, |e| e.parse().unwrap())); 0 }

fn functionconditional(enable: bool) { failpoint!("name3", enable, |_| {}); } ```

Trigger a fail point via the environment variable:

$ FAILPOINTS=foo=panic cargo run

In unit tests:

```

[test]

fn test_foo() { fail::cfg("foo", "panic"); foo(); } ```

Caveats

Before putting any fail points, you should carefully consider the consequences. A list of suggestions you should keep in mind:

• Enable the no_fail feature in the release build.
• Be careful about the complex combination.
• Be careful about the fail point name and make sure it is self-described.
• Fail points might have the same name, and in this case, they take the same actions.

To Do

Triggering a fail point via the HTTP API is planned but not implemented yet.