Note: Runnable examples are available here
Golang is great. I mostly love it. However, collecting an error with relevant context and a nicely formatted stacktrace is kind of a mess of competing approaches. This this feature comparison is a good overview of the landscape.
I wanted to compare the output of a few different "nicely formatted" approaches with two different kinds of wrapped
errors, Sentinel errors and custom error types.
Some libraries capture the exact state of the stack when an error happens, including every function call.
Some try to attach relevant contextual information (messages, variables) at strategic places along the call stack,
keeping stack traces compact and maximally useful.
Some eliminate stacktrace duplication from wrapped errors.
{Msg:This is a message Detail:Important detail Err:reading "file"
cmd/prog/reader.go:122
parsing line 23
iff x > 3 {
cmd/prog/parser.go:85
syntax error
cmd/prog/parser.go:214
}
something went wrong
main.foo
/Users/steve/Documents/git/comparerr/emperror/main.go:23
main.main
/Users/steve/Documents/git/comparerr/emperror/main.go:31
runtime.main
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:203
runtime.goexit
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/asm_amd64.s:1373
starting bar
something went wrong
got an error in bar
main.bar
/Users/steve/Documents/git/comparerr/emperror/main.go:27
main.main
/Users/steve/Documents/git/comparerr/emperror/main.go:39
runtime.main
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:203
runtime.goexit
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/asm_amd64.s:1373
Sentinel Something Went Wrong
(1) attached stack trace
-- stack trace:
| main.foo
| /Users/steve/Documents/git/comparerr/cockroachdb-errors/main.go:23
| main.main
| /Users/steve/Documents/git/comparerr/cockroachdb-errors/main.go:31
| [...repeated from below...]
Wraps: (2) attached stack trace
-- stack trace:
| main.init
| /Users/steve/Documents/git/comparerr/cockroachdb-errors/main.go:10
| runtime.doInit
| /Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:5480
| runtime.main
| /Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:190
| runtime.goexit
| /Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/asm_amd64.s:1373
Wraps: (3) Sentinel Something Went Wrong
Error types: (1) *withstack.withStack (2) *withstack.withStack (3) *errutil.leafError
starting bar
got an error in bar: bar something went wrong
(1) attached stack trace
-- stack trace:
| main.bar
| /Users/steve/Documents/git/comparerr/cockroachdb-errors/main.go:27
| main.main
| /Users/steve/Documents/git/comparerr/cockroachdb-errors/main.go:39
| runtime.main
| /Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:203
| runtime.goexit
| /Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/asm_amd64.s:1373
Wraps: (2) got an error in bar
Wraps: (3) bar something went wrong
Error types: (1) *withstack.withStack (2) *errutil.withPrefix (3) main.ErrMyError
foo returned error
--- at /Users/steve/Documents/git/comparerr/palantir-err/main.go:22 (foo) ---
Caused by: Sentinel Something Went Wrong
--- at /Users/steve/Documents/git/comparerr/palantir-err/main.go:9 (init) ---
starting bar
got an error in bar
--- at /Users/steve/Documents/git/comparerr/palantir-err/main.go:26 (bar) ---
Caused by: bar something went wrong
Sentinel Something Went Wrong
main.init
/Users/steve/Documents/git/comparerr/pkg-errors/main.go:10
runtime.doInit
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:5480
runtime.main
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:190
runtime.goexit
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/asm_amd64.s:1373
main.foo
/Users/steve/Documents/git/comparerr/pkg-errors/main.go:23
main.main
/Users/steve/Documents/git/comparerr/pkg-errors/main.go:31
runtime.main
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:203
runtime.goexit
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/asm_amd64.s:1373
starting bar
bar something went wrong
got an error in bar
main.bar
/Users/steve/Documents/git/comparerr/pkg-errors/main.go:27
main.main
/Users/steve/Documents/git/comparerr/pkg-errors/main.go:39
runtime.main
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/proc.go:203
runtime.goexit
/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/asm_amd64.s:1373
You can clone this repo, cd into any of the directories and run go run main.go
to see an example
- jba errfmt output example
- emperror output example
- cockroackdb/errors playground times out? Not sure what that is all about.
- pkg/errors
- palantir/stacktrace
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