Parses panic stack traces, densifies and deduplicates goroutines with similar stack traces. Helps debugging crashes and deadlocks in heavily parallelized process.
panicparse helps make sense of Go crash dumps:
- New in v1.4.0!: webstack.SnapshotHandler is a http handler that serves a very tight and swell snapshot of your goroutines, much more readable than net/http/pprof.
- >50% more compact output than original stack dump yet more readable.
- Exported symbols are bold, private symbols are darker.
- Stdlib is green, main is yellow, rest is red.
- Deduplicates redundant goroutine stacks. Useful for large server crashes.
- Arguments as pointer IDs instead of raw pointer values.
- Pushes stdlib-only stacks at the bottom to help focus on important code.
- Parses the source files if available to augment the output.
- Works on Windows.
webstack in action
panicparse was created with ❤️️ and passion by Marc-Antoine
go get github.com/maruel/panicparse/cmd/pp
Piping a stack trace from another process
- Ubuntu (bash v4 or zsh):
- macOS, install bash 4+, then:
- Windows or macOS with stock bash v3:
- Fish shell:
pp streams its stdin to stdout as long as it doesn't detect any panic.
panic() and Go's native deadlock detector print to
stderr via the native
Bash v4 or zsh:
|& tells the shell to redirect stderr to stdout,
it's an alias for
2>&1 | (bash
go test -v |&pp
Windows or macOS native bash (which is 3.2.57): They don't have this shortcut, so use the long form:
go test -v 2>&1 | pp
Fish: It uses ^ for stderr
so the shortcut is
go test -v ^|pp
PowerShell: It has broken
2>&1 redirection. The workaround is to shell out to cmd.exe. :(
On POSIX, use
Ctrl-\ to send SIGQUIT to your process,
pp will ignore
the signal and will parse the stack trace.
Parsing from a file
To dump to a file then parse, pass the file path of a stack trace
go test 2> stack.txt pp stack.txt
Starting with go1.11, the toolchain starts to inline more often. This causes traces to be less informative. You can use the following to help diagnosing issues:
go install -gcflags '-l' path/to/foo foo |& pp
go test -gcflags '-l' ./... |& pp
Starting with Go 1.6,
single instead of
1 that was used in 1.5 and before. To get all
goroutines trace and not just the crashing one, set the environment variable:
set GOTRACEBACK=all on Windows. Probably worth to put it in your
Updating bash on macOS
Install bash v4+ on macOS via homebrew or macports. Your future self will appreciate having done that.
If you have
If you try
pp for the first time and you get:
Creating tables and indexes... Done.
/usr/bin/pp5.18: No input files specified
you may be running the Perl PAR Packager instead of panicparse.
You have two choices, either you put
$GOPATH/bin at the beginning of
or use long name
go get github.com/maruel/panicparse
panicparse instead of
go test 2> panicparse
panicparse: analyzes stack dump of Go processes and simplifies it.
It is mostly useful on servers will large number of identical goroutines, making the crash dump harder to read than strictly necessary.
panic crashes in various ways.
|panic crashes in various ways.|
Package internal is for use for panic.
|Package internal is for use for panic.|
Package correct is in directory incorrect.
|Package correct is in directory incorrect.|
Package ùtf8 tests a package and function with non-ASCII names.
|Package ùtf8 tests a package and function with non-ASCII names.|
panicweb implements a simulation of a web server that panics.
|panicweb implements a simulation of a web server that panics.|
Package internal implements the handlers for panicweb so they are in a separate package than "main".
|Package internal implements the handlers for panicweb so they are in a separate package than "main".|
pp: analyzes stack dump of Go processes and simplifies it.
|pp: analyzes stack dump of Go processes and simplifies it.|
Package internal implements panicparse It is mostly useful on servers will large number of identical goroutines, making the crash dump harder to read than strictly necessary.
|Package internal implements panicparse It is mostly useful on servers will large number of identical goroutines, making the crash dump harder to read than strictly necessary.|
Package stack analyzes stack dump of Go processes and simplifies it.
|Package stack analyzes stack dump of Go processes and simplifies it.|
Package webstack provides a http.HandlerFunc that serves a snapshot similar to net/http/pprof.Index().
|Package webstack provides a http.HandlerFunc that serves a snapshot similar to net/http/pprof.Index().|