Crate slog_unwraps

Syntactic sugar to slog an error before unwrapping. It will add caller file and line information to the log statement, but know that that only makes sense in debug mode. In release mode this information will either be missing or unreliable.

Anyways, this is meant to make your life easier while developping. It will also report file and line number of the unwraps so you don't have to turn on RUST_BACKTRACE to see what went wrong.

At first I had an expects function as well to be able to add context, but I really think you should use the failure crate, which provides a context method on errors, and it's much cleaner, so expects no longer exists. If you don't want to use failure, you will have to make sure your errors display sensible messages.

Example

run with cargo run --example basic

use
{
   std          :: { fs::File                       } ,
   slog         :: { Drain, Level, Logger, o, crit  } ,
   slog_term    :: { FullFormat, PlainSyncDecorator } ,
   slog_unwraps :: { ResultExt                      } ,
};

fn main()
{
   let plain = PlainSyncDecorator::new( std::io::stderr() )                  ;
   let log   = Logger::root( FullFormat::new( plain ).build().fuse(), o!() ) ;


   // This will output (in one line, wrapped here for readablility):
   //
   // Mar 08 18:13:52.034 CRIT PANIC - fn `main` calls `unwraps` @ examples/basic.rs:20
   // -> Error: No such file or directory (os error 2)
   //
   // and then will call unwrap for you
   //
   let f     = File::open( "dont.exist" );
   let _file = f.unwraps( &log );


   // This is equivalent. Of course you can do something else with the result after logging
   // rather than unwrapping. This only logs if the result is an error.
   //
   let g     = File::open( "dont.exist" );
   let _file = g.log( &log, Level::Critical ).unwrap();

   // Without this crate, everytime you want to unwrap, you would write something like:
   //
   let h     = File::open( "dont.exist" );

   let _file = match h
   {
      Ok ( f ) => f,
      Err( e ) => { crit!( log, "{}", e ); panic!() }
   };
}

Traits

ResultExt

Extends the std::result::Result type with extra methods to ease logging of errors.