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https://github.com/uber-archive/go-torch

Stochastic flame graph profiler for Go programs
https://github.com/uber-archive/go-torch

Last synced: about 2 months ago
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Stochastic flame graph profiler for Go programs

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# go-torch [![Build Status](https://travis-ci.org/uber/go-torch.svg?branch=master)](https://travis-ci.org/uber/go-torch) [![Coverage Status](http://coveralls.io/repos/uber/go-torch/badge.svg?branch=master&service=github)](http://coveralls.io/github/uber/go-torch?branch=master) [![GoDoc](https://godoc.org/github.com/uber/go-torch?status.svg)](https://godoc.org/github.com/uber/go-torch)

## go-torch is deprecated, use pprof instead

As of Go 1.11, flamegraph visualizations are available in `go tool pprof` directly!

```
# This will listen on :8081 and open a browser.
# Change :8081 to a port of your choice.
$ go tool pprof -http=":8081" [binary] [profile]
```

If you cannot use Go 1.11, you can get the latest `pprof` tool and use it instead:

```
# Get the pprof tool directly
$ go get -u github.com/google/pprof

$ pprof -http=":8081" [binary] [profile]
```

## Synopsis

Tool for stochastically profiling Go programs. Collects stack traces and
synthesizes them into a flame graph. Uses Go's built in [pprof][] library.

[pprof]: https://golang.org/pkg/net/http/pprof/

## Example Flame Graph

[![Inception](http://uber.github.io/go-torch/meta.svg)](http://uber.github.io/go-torch/meta.svg)

## Basic Usage

```
$ go-torch -h
Usage:
go-torch [options] [binary]

pprof Options:
-u, --url= Base URL of your Go program (default: http://localhost:8080)
-s, --suffix= URL path of pprof profile (default: /debug/pprof/profile)
-b, --binaryinput= File path of previously saved binary profile. (binary profile is anything accepted by https://golang.org/cmd/pprof)
--binaryname= File path of the binary that the binaryinput is for, used for pprof inputs
-t, --seconds= Number of seconds to profile for (default: 30)
--pprofArgs= Extra arguments for pprof

Output Options:
-f, --file= Output file name (must be .svg) (default: torch.svg)
-p, --print Print the generated svg to stdout instead of writing to file
-r, --raw Print the raw call graph output to stdout instead of creating a flame graph; use with Brendan Gregg's flame graph perl script (see https://github.com/brendangregg/FlameGraph)
--title= Graph title to display in the output file (default: Flame Graph)
--width= Generated graph width (default: 1200)
--hash Colors are keyed by function name hash
--colors= Set color palette. Valid choices are: hot (default), mem, io, wakeup, chain, java,
js, perl, red, green, blue, aqua, yellow, purple, orange
--hash Graph colors are keyed by function name hash
--cp Graph use consistent palette (palette.map)
--inverted Icicle graph
Help Options:
-h, --help Show this help message
```

### Write flamegraph using /debug/pprof endpoint

The default options will hit `http://localhost:8080/debug/pprof/profile` for
a 30 second CPU profile, and write it out to torch.svg

```
$ go-torch
INFO[19:10:58] Run pprof command: go tool pprof -raw -seconds 30 http://localhost:8080/debug/pprof/profile
INFO[19:11:03] Writing svg to torch.svg
```

You can customize the base URL by using `-u`

```
$ go-torch -u http://my-service:8080/
INFO[19:10:58] Run pprof command: go tool pprof -raw -seconds 30 http://my-service:8080/debug/pprof/profile
INFO[19:11:03] Writing svg to torch.svg
```

Or change the number of seconds to profile using `--seconds`:

```
$ go-torch --seconds 5
INFO[19:10:58] Run pprof command: go tool pprof -raw -seconds 5 http://localhost:8080/debug/pprof/profile
INFO[19:11:03] Writing svg to torch.svg
```

### Using pprof arguments

`go-torch` will pass through arguments to `go tool pprof`, which lets you take
existing pprof commands and easily make them work with `go-torch`.

For example, after creating a CPU profile from a benchmark:
```
$ go test -bench . -cpuprofile=cpu.prof

# This creates a cpu.prof file, and the $PKG.test binary.
```

The same arguments that can be used with `go tool pprof` will also work
with `go-torch`:
```
$ go tool pprof main.test cpu.prof

# Same arguments work with go-torch
$ go-torch main.test cpu.prof
INFO[19:00:29] Run pprof command: go tool pprof -raw -seconds 30 main.test cpu.prof
INFO[19:00:29] Writing svg to torch.svg
```

Flags that are not handled by `go-torch` are passed through as well:
```
$ go-torch --alloc_objects main.test mem.prof
INFO[19:00:29] Run pprof command: go tool pprof -raw -seconds 30 --alloc_objects main.test mem.prof
INFO[19:00:29] Writing svg to torch.svg
```

## Integrating With Your Application

To add profiling endpoints in your application, follow the official
Go docs [here][].
If your application is already running a server on the DefaultServeMux,
just add this import to your application.

[here]: https://golang.org/pkg/net/http/pprof/

```go
import _ "net/http/pprof"
```

If your application is not using the DefaultServeMux, you can still easily
expose pprof endpoints by manually registering the net/http/pprof handlers or by
using a library like [this one](https://github.com/e-dard/netbug).

## Installation

```
$ go get github.com/uber/go-torch
```

You can also use go-torch using docker:
```
$ docker run uber/go-torch -u http://[address-of-host] -p > torch.svg
```

Using `-p` will print the SVG to standard out, which can then be redirected
to a file. This avoids mounting volumes to a container.

### Get the flame graph script:

When using the `go-torch` binary locally, you will need the Flamegraph scripts
in your `PATH`:

```
$ cd $GOPATH/src/github.com/uber/go-torch
$ git clone https://github.com/brendangregg/FlameGraph.git
```

## Development and Testing

### Install the Go dependencies:

```
$ go get github.com/Masterminds/glide
$ cd $GOPATH/src/github.com/uber/go-torch
$ glide install
```

### Run the Tests

```
$ go test ./...
ok github.com/uber/go-torch 0.012s
ok github.com/uber/go-torch/graph 0.017s
ok github.com/uber/go-torch/visualization 0.052s
```