Crate checked_command

In std the methods used to retrieve the ExitStatus/Output from executing a Command do not consider the exit status when deciding weather or not the function returns a error.

This creates provides:

1. A CheckedCommand and CheckedChild struct, which wrap std::process::Command and std::process::Child replacing status(),output(),wait() and wait_with_output() with a version which will check the ExitStatus and if it didn’t succeed they will return a Err(...) instead of a Ok(...).

2. A CommandExt and ChildExt extension trait which provide versions of status(), output() etc. which check the ExitStatus returning a Err(...) if the exit status is non successful (i.e. there is no exit code or it is not equal zero). The checked methods are checked_status(), checked_output(), checked_wait(), checked_wait_with_output(). The CheckedCommand and CheckedChild wrapper use this methods as their status()/output() etc. methods.

In case of functions originally returning a Output it might be necessary to process the Output even if the command returned a non-successful exit status. For this reason the Output is included into the error Error::Failure variant (as option as not all functions provide a output)

Note that the provided functions do return their own Output struct instead of std::process::Output which differs in that it does not contain a status field (which is also not anymore needed for the new methods). There is use_std_output feature which will make the crate use the std’s output implementation instead.

Example

use checked_command::{ Error, CheckedCommand };

let result = CheckedCommand::new("ls")
                .arg("--badbadbad").arg("--")
                .output();

match result {
    Ok(_) => panic!("ls should have failed"),
    Err(Error::Io(io_err)) => panic!("unexpected I/O Error: {:?}", io_err),
    Err(Error::Failure(ex, output)) => {
        println!("failed with exit code: {:?}", ex.code());
        if let Some(output) = output {
            println!("error output was:\n{}",
                     String::from_utf8_lossy(&*output.stderr));
        }
    }
}

Features

process_try_wait

Requires nightly rust as the rust feature process_try_wait is required.

Adds a checked_try_wait method to ChildExt as well as a try_wait method to CheckedChild (which uses checked_try_wait internally). Both methods call the unstable std::process::Child::try_wait method internally.

command_envs

Requires nightly rust as the rust feature command_envs is required.

Adds a envs method to CheckedCommand which calls the unstable std::process::Command::env method.

use_std_output

Works with stable.

This crate uses normally it’s own Output struct, with this option the std::process::Output is used instead, which differs in that it has an additional status: ExitStatus field.

enable_integration_tests

Works with stable.

Enable integration tests for this crate.

Structs

CheckedChild

A wrapper around std::process::Child which hides the original wait/wait_with_output methods and replaces it with the versions from checked_command::ChildExt

CheckedCommand

A wrapper around std::process::Command which hides the original status/output methods and replaces them with the versions from checked_command::CommandExt

Output

custom output type which, diferently to std::process::Output is not closely coupled with ExitStatus (it does not have a status field)

Enums

Error

error type representing either a io::Error or a failure caused by a non-successful exit status i.e. without exit code or a exit code not equal zero.

Traits

ChildExt

Extension to std::process::Child adding versions of the wait_with_output/wait functions which also fail/error with a non-success exit status

CommandExt

Extension to std::process::Command adding versions of the output/status functions which also fail/error with a non-success exit status