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.
- jba/errfmt
{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 } - emperror
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 - cockroachdb/errors
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 - palantir/stacktrace
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 - pkg/errors
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 - Panic Parse creates detailed HTML reports as well as rich structures:
parsedStack stack.Stack{ Calls: { { Func: stack.Func{ Complete: "runtime/debug.Stack", ImportPath: "runtime/debug", DirName: "debug", Name: "Stack", IsExported: true, IsPkgMain: false, _: struct {}{}, }, Args: stack.Args{ Values: { { Value: 0x12011b9, Name: "", IsPtr: true, _: struct {}{}, }, { Value: 0xb, Name: "", IsPtr: false, _: struct {}{}, }, { Value: 0x1245b40, Name: "", IsPtr: true, _: struct {}{}, }, }, Processed: {"0x12011b9", "0xb", "0x1245b40"}, Elided: false, _: struct {}{}, }, RemoteSrcPath: "/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/debug/stack.go", Line: 24, SrcName: "stack.go", DirSrc: "debug/stack.go", LocalSrcPath: "/Users/steve/.asdf/installs/golang/1.14.15/go/src/runtime/debug/stack.go", RelSrcPath: "runtime/debug/stack.go", ImportPath: "runtime/debug", Location: 4, _: struct {}{}, }, { Func: stack.Func{ Complete: "main.main", ImportPath: "main", DirName: "main", Name: "main", IsExported: true, IsPkgMain: true, _: struct {}{}, }, Args: stack.Args{}, RemoteSrcPath: "/Users/steve/Documents/git/comparerr/panicparse-err/main.go", Line: 38, SrcName: "main.go", DirSrc: "panicparse-err/main.go", LocalSrcPath: "/Users/steve/Documents/git/comparerr/panicparse-err/main.go", RelSrcPath: "main.go", ImportPath: "github.com/StevenACoffman/comparerr/panicparse-err", Location: 1, _: struct {}{}, }, }, Elided: false, _: struct {}{}, }
You can clone this repo, cd into any of the directories and run go run main.go to see an example
Here are some runnable go playground examples:
- jba errfmt output example
- emperror output example
- cockroackdb/errors playground times out? Not sure what that is all about.
- pkg/errors
- palantir/stacktrace
- maruel/panicparse