panicparse

panicparse

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:

Features

• >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.
• Usable as a library!
  • Warning: please pin the major version (i.e. vendor it via dep) as breaking changes happen on major version update.
• Parses the source files if available to augment the output.

Usage

Piping a stack trace from another process

TL;DR

• Ubuntu (bash v4 or zsh): |&
• Fish shell: ^|

Longer version

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 print() function.

Bash v4 or zsh: |& tells the shell to redirect stderr to stdout, it's an alias for 2>&1 | (bash v4, zsh):

go test -v |&pp

Fish: It uses ^ for stderr redirection so the shortcut is ^|:

go test -v ^|pp

Investigate deadlock

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

Tips

GOTRACEBACK

GOTRACEBACK defaults to single.

To get all goroutines trace and not just the crashing one, set the environment variable:

export GOTRACEBACK=all

Probably worth to put it in your .bashrc.

If you have /usr/bin/pp installed

If you try pp for the first time and you get:

Creating tables and indexes...
Done.

and/or

/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 begining of $PATH or use panicparse instead of pp:

go test 2> panicparse