Fault is a library that helps with package internal error handling in Go.
It supports a simple idiom for reducing the amount of package internal error handling. It allows you to panic with a Fault instance in package internal code. This is then recovered using a defer for a all exported methods, which then return an error extracted from the fault. As an example, if you were to be reading data from a file and then writing it you could use
import (
"github.com/surullabs/fault"
)
var check = fault.NewChecker()
func ExportedMethod() (err error) {
// Set up the recovery. err will be automatically populated and all
// non-fault panics will be propogated.
defer check.Recover(&err)
// If there is an error in ReadFile the method will automatically return
// the error.
data := check.Return(ioutil.ReadFile("filename")).([]byte)
// If yourFn returns false the function will return an error
// formatted as "condition is not true: yourData"
check.Truef(yourFn(data), "condition is not true: %s", string(data))
}
It also provides access to an ErrorChain class which can be used to chain errors together. Errors can be transparently checked for existence in a chain by calling the Contains method.
NOTE: The API is still not final and will be changed as better usage patterns emerge
Please consult the package GoDoc for detailed documentation.
On an 2.000 GHz Intel i7-2630QM CPU there was ~70 ns overhead per CheckReturn call with 164 ns overhead for the call to Recover(...). The results of the naive benchmarks in the package are below (formatted for clarity)
BenchmarkNormalSuccess 200000000 8.50 ns/op
BenchmarkNormalFailure 200000000 8.98 ns/op
BenchmarkCheckReturnFailure 2000000 941 ns/op
BenchmarkCheckReturnOnly 20000000 77.8 ns/op
BenchmarkCheckRecoverOnlyNoError 10000000 164 ns/op
If you wish to test the overhead on your machine please run
go test github.com/surullabs/fault -bench .
Fault is licensed under a 3-Clause BSD license. Please consult the LICENSE file for details.
We also ask that you please file bugs and enhancement requests if you run into any problems. In additon, we're always happy to accept pull requests! If you do find this useful please share it with others who might also find it useful. The more users we have the better the software becomes.