statsviz

package module
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 Go to latest Published: Oct 8, 2023 License: MIT Imports: 13 Imported by: 84

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Statsviz

Statsviz Gopher Logo statsviz ui


Visualize real time plots of your Go program runtime metrics, including heap, objects, goroutines, GC pauses, scheduler and more, in your browser.

Install

Download the latest version:

go get github.com/arl/statsviz@latest

Please note that, as new metrics are added to the /runtime/metrics package, new plots are added to Statsviz. This also means that the presence of some plots on the dashboard depends on the Go version you're using.

When in doubt, use the latest ;-)

Usage

Register Statsviz HTTP handlers with your application http.ServeMux.

mux := http.NewServeMux()
statsviz.Register(mux)

go func() {
    log.Println(http.ListenAndServe("localhost:8080", mux))
}()

Open your browser at http://localhost:8080/debug/statsviz

Advanced Usage

If you want more control over Statsviz HTTP handlers, examples are:

  • you're using some HTTP framework
  • you want to place Statsviz handler behind some middleware

then use statsviz.NewServer to obtain a Server instance. Both the Index() and Ws() methods return http.HandlerFunc.

srv, err := statsviz.NewServer(); // Create server or handle error
srv.Index()                       // UI (dashboard) http.HandlerFunc
srv.Ws()                          // Websocket http.HandlerFunc

Please look at examples of usage in the Examples directory.

How Does That Work?

statsviz.Register registers 2 HTTP handlers within the given http.ServeMux:

  • the Index handler serves Statsviz user interface at /debug/statsviz at the address served by your program.

  • The Ws serves a Websocket endpoint. When the browser connects to that endpoint, runtime/metrics are sent to the browser, once per second.

Data points are in a browser-side circular-buffer.

Documentation

Go API

Check out the API reference on pkg.go.dev.

User interface

Controls at the top of the page act on all plots:

menu
  • the groom shows/hides the vertical lines representing garbage collections.
  • the time range selector defines the visualized time span.
  • the play/pause icons stops and resume the refresh of the plots.
  • the light/dark selector switches between light and dark modes.

On top of each plot there are 2 icons:

menu
  • the camera downloads a PNG image of the plot.
  • the info icon shows details about the metrics displayed.
Plots

Depending on your go version, some plots may not be available.

Heap (global)
heap-global
Heap (details)
heap-details
Live Objects in Heap
live-objects
Live Bytes in Heap
live-bytes
MSpan/MCache
mspan-mcache
Memory classes
memory-classes
Goroutines
goroutines
Size Classes
size-classes
GC Scan
gc-scan
GC Cycles
gc-cycles
Stop-the-world Pause Latencies
gc-pauses
CPU Classes (GC)
cpu-classes-gc
Time Goroutines Spend in 'Runnable' state
runnable-time
Time Goroutines Spend Blocked on Mutexes
mutex-wait
Starting Size of Goroutines Stacks
gc-stack-size
Goroutine Scheduling Events
sched-events
CGO Calls
cgo
User Plots

Since v0.6 you can add your own plots to Statsviz dashboard, in order to easily visualize your application metrics next to runtime metrics.

Please see the userplots example.

Examples

Check out the _example directory to see various ways to use Statsviz, such as:

  • use of http.DefaultServeMux or your own http.ServeMux
  • wrap HTTP handler behind a middleware
  • register the web page at /foo/bar instead of /debug/statsviz
  • use https:// rather than http://
  • register Statsviz handlers with various Go HTTP libraries/frameworks:

Questions / Troubleshooting

Either use GitHub's discussions or come to say hi and ask a live question on #statsviz channel on Gopher's slack.

Contributing

Please use issues for bugs and feature requests.
Pull-requests are always welcome!
More details in CONTRIBUTING.md.

Changelog

See CHANGELOG.md.

License: MIT

See LICENSE

Documentation

Overview

Package statsviz allows visualizing Go runtime metrics data in real time in your browser.

Register a Statsviz HTTP handlers with your server's http.ServeMux (preferred method): 

mux := http.NewServeMux()
statsviz.Register(mux)

Alternatively, you can register with http.DefaultServeMux: 

ss := statsviz.Server{}
s.Register(http.DefaultServeMux)

By default, Statsviz is served at http://host:port/debug/statsviz/. This, and other settings, can be changed by passing some Option to NewServer.

If your application is not already running an HTTP server, you need to start one. Add "net/http" and "log" to your imports, and use the following code in your main function: 

go func() {
    log.Println(http.ListenAndServe("localhost:8080", nil))
}()

Then open your browser and visit http://localhost:8080/debug/statsviz/.

Advanced usage:

If you want more control over Statsviz HTTP handlers, examples are:

  • you're using some HTTP framework
  • you want to place Statsviz handler behind some middleware

then use NewServer to obtain a Server instance. Both the Server.Index and Server.Ws() methods return http.HandlerFunc. 

srv, err := statsviz.NewServer(); // Create server or handle error
srv.Index()                       // UI (dashboard) http.HandlerFunc
srv.Ws()                          // Websocket http.HandlerFunc

Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrNoTimeSeries is returned when a user plot has no time series.
	ErrNoTimeSeries = errors.New("user plot must have at least one time series")

	// ErrEmptyPlotName is returned when a user plot has an empty name.
	ErrEmptyPlotName = errors.New("user plot name can't be empty")
)

Functions

func Register 

func Register(mux *http.ServeMux, opts ...Option) error

Register registers the Statsviz HTTP handlers on the provided mux.

func RegisterDefault 

func RegisterDefault(opts ...Option) error

RegisterDefault registers the Statsviz HTTP handlers on http.DefaultServeMux.

RegisterDefault should not be used in production.

Types

type BarMode added in v0.6.0 

type BarMode string

BarMode determines how bars at the same location are displayed on a bar plot. 

const (
	// Stack indicates that bars are stacked on top of one another.
	Stack BarMode = "stack"

	// Ggroup indicates that bars are plotted next to one another, centered
	// around the shared location.
	Group BarMode = "group"

	// Relative indicates that bars are stacked on top of one another, with
	// negative values below the axis and positive values above.
	Relative BarMode = "relative"

	// Overlay indicates that bars are plotted over one another.
	Overlay BarMode = "overlay"
)

type ErrReservedPlotName added in v0.6.0 

type ErrReservedPlotName string

ErrReservedPlotName is returned when a reserved plot name is used for a user plot.

func (ErrReservedPlotName) Error added in v0.6.0 

func (e ErrReservedPlotName) Error() string

type HoverOnType added in v0.6.0 

type HoverOnType string

HoverOnType describes the type of hover effect on a time series plot. 

const (
	// HoverOnPoints specifies that the hover effects highlights individual
	// points.
	HoverOnPoints HoverOnType = "points"

	// HoverOnPoints specifies that the hover effects highlights filled regions.
	HoverOnFills HoverOnType = "fills"

	// HoverOnPointsAndFills specifies that the hover effects highlights both
	// points and filled regions.
	HoverOnPointsAndFills HoverOnType = "points+fills"
)

type Option added in v0.6.0 

type Option func(*Server) error

Option is a configuration option for the Server.

func Root added in v0.2.0 

func Root(path string) Option

Root changes the root path of the Statsviz user interface. The default is "/debug/statsviz".

func SendFrequency added in v0.2.0 

func SendFrequency(intv time.Duration) Option

SendFrequency changes the interval between successive acquisitions of metrics and their sending to the user interface. The default interval is one second.

func TimeseriesPlot added in v0.6.0 

func TimeseriesPlot(tsp TimeSeriesPlot) Option

TimeseriesPlot adds a new time series plot to Statsviz. This options can be added multiple times.

type Server added in v0.6.0 

type Server struct {
	// contains filtered or unexported fields
}

Server is the core component of Statsviz. It collects and periodically updates metrics data and provides two essential HTTP handlers:

  • the Index handler serves Statsviz user interface, allowing you to visualize runtime metrics on your browser.
  • The Ws handler establishes a WebSocket connection allowing the connected browser to receive metrics updates from the server.

The zero value is not a valid Server, use NewServer to create a valid one.

func NewServer added in v0.6.0 

func NewServer(opts ...Option) (*Server, error)

NewServer constructs a new Statsviz Server with the provided options, or the default settings.

Note that once the server is created, its HTTP handlers needs to be registered with some HTTP server. You can either use the Register method or register yourself the Index and Ws handlers.

func (*Server) Index added in v0.6.0 

func (s *Server) Index() http.HandlerFunc

Index returns the index handler, which responds with the Statsviz user interface HTML page. By default, the handler is served at the path specified by the root. Use [WithRoot] to change the path.

func (*Server) Register added in v0.6.0 

func (s *Server) Register(mux *http.ServeMux)

Register registers the Statsviz HTTP handlers on the provided mux.

func (*Server) Ws added in v0.6.0 

func (s *Server) Ws() http.HandlerFunc

Ws returns the WebSocket handler used by Statsviz to send application metrics. The underlying net.Conn is used to upgrade the HTTP server connection to the WebSocket protocol.

type TimeSeries added in v0.6.0 

type TimeSeries struct {
	// Name is the name identifying this time series in the user interface.
	Name string

	// UnitFmt is the d3-format string used to format the numbers of this time
	// series in the user interface. See https://github.com/d3/d3-format.
	Unitfmt string

	// HoverOn configures whether the hover effect highlights individual points
	// or do they highlight filled regions, or both. Defaults to HoverOnFills.
	HoverOn HoverOnType

	// Type is the time series type, either [Scatter] or [Bar]. default: [Scatter].
	Type TimeSeriesType

	// GetValue specifies the function called to get the value of this time
	// series.
	GetValue func() float64
}

A TimeSeries describes a single time series of a plot.

type TimeSeriesPlot added in v0.6.0 

type TimeSeriesPlot struct {
	// contains filtered or unexported fields
}

TimeSeriesPlot is an opaque type representing a timeseries plot. A plot can be created with TimeSeriesPlotConfig.Build.

type TimeSeriesPlotConfig added in v0.6.0 

type TimeSeriesPlotConfig struct {
	// Name is the plot name, it must be unique.
	Name string

	// Title is the plot title, shown above the plot.
	Title string

	// Type is either [Scatter] or [Bar]. default: [Scatter].
	Type TimeSeriesType

	// BarMode is either [Stack], [Group], [Relative] or [Overlay].
	// default: [Group].
	BarMode BarMode

	// Tooltip is the html-aware text shown when the user clicks on the plot
	// Info icon.
	InfoText string

	// YAxisTitle is the title of Y axis.
	YAxisTitle string

	// YAxisTickSuffix is the suffix added to tick values.
	YAxisTickSuffix string

	// Series contains the time series shown on this plot, there must be at
	// least one.
	Series []TimeSeries
}

TimeSeriesPlotConfig describes the configuration of a time series plot.

func (TimeSeriesPlotConfig) Build added in v0.6.0 

func (p TimeSeriesPlotConfig) Build() (TimeSeriesPlot, error)

Build validates the configuration and builds a time series plot for it

type TimeSeriesType added in v0.6.0 

type TimeSeriesType string

TimeSeriesType describes the type of a time series plot. 

const (
	// Scatter is a time series plot made of lines.
	Scatter TimeSeriesType = "scatter"

	// Bar is a time series plot made of bars.
	Bar TimeSeriesType = "bar"
)

Source Files

View all Source files

Directories

Path Synopsis
internal
plot
static

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