debugserver

README

debugserver

Note: This repository should be imported as code.cloudfoundry.org/debugserver.

A helper function for running a pre-configured pprof server in go.

Reporting issues and requesting features

Please report all issues and feature requests in cloudfoundry/diego-release.

Endpoints

• /log-level

Sets the log level of the sink passed to the Runner method. This endpoint expects the request method to be POST or PUT and uses the body of the request as the new log level. For example, curl -X POST --data 'debug' http://host:port/log-level will set the log level to debug.

• /debug/pprof/cmdline

Responds with the running program's command line, with arguments separated by NUL bytes.

• /debug/pprof/profile

Responds with the pprof-formatted CPU profile.

• /debug/pprof/heap

Responds with the pprof-formatted heap profile.

• /debug/pprof/block

Responds with the pprof-formatted goroutine blocking profile.

• /debug/pprof/trace?seconds=n

Responds with the pprof-formatted execution trace for n seconds.

• /debug/pprof/symbol

Looks up the program counters listed in the request, responding with a table mapping program counters to function names.

• /block-profile-rate

Controls the fraction of goroutine blocking events that are reported in the blocking profile. The profiler aims to sample an average of one blocking event per rate nanoseconds spent blocked. To include every blocking event in the profile, pass rate = 1. To turn off profiling entirely, pass rate <= 0.

• /debug/pprof/goroutine?debug=2

Responds with the full goroutine stack dump.

• /debug/pprof/<tracename>

Responds with the trace specified by tracename. See: https://golang.org/pkg/net/http/pprof/#Index

Remote debugging

Assuming port forwarding is enabled on the local machine from port 17017 to the debug server, a program profile can be obtained by running the following command:

go tool pprof -seconds=5 http://localhost:17017/debug/pprof/profile

Please see Profiling Go Programs for further information on how to use the go pprof tool.

License

debugserver is licensed under Apache 2.0.

Documentation

Index

• Constants
• func AddFlags(flags *flag.FlagSet)
• func DebugAddress(flags *flag.FlagSet) string
• func Handler(sink *lager.ReconfigurableSink) http.Handler
• func Run(address string, sink *lager.ReconfigurableSink) (ifrit.Process, error)
• func Runner(address string, sink *lager.ReconfigurableSink) ifrit.Runner
• type DebugServerConfig

Constants

const (
	DebugFlag = "debugAddr"
)

Functions

func AddFlags

func AddFlags(flags *flag.FlagSet)

func DebugAddress

func DebugAddress(flags *flag.FlagSet) string

func Handler

func Handler(sink *lager.ReconfigurableSink) http.Handler

func Run

func Run(address string, sink *lager.ReconfigurableSink) (ifrit.Process, error)

func Runner

func Runner(address string, sink *lager.ReconfigurableSink) ifrit.Runner

Types

type DebugServerConfig

type DebugServerConfig struct {
	DebugAddress string `json:"debug_address"`
}