GoLang调用链可视化go-callvis使用介绍

本文介绍一款工具 go-callvis，它能够将 Go 代码的调用关系可视化出来，并提供了可交互式的 web 服务。

go get -u github.com/ofabry/go-callvis
在windows系统上并没有自动安装，需要进入下载的目录go install
在linux系统上自动安装了

> go-callvis

go-callvis: visualize call graph of a Go program.

Usage:

  go-callvis [flags] package

  Package should be main package, otherwise -tests flag must be used.

Flags:

  -debug
        Enable verbose log.
  -file string
        output filename - omit to use server mode
  -focus string
        Focus specific package using name or import path. (default "main")
  -format string
        output file format [svg | png | jpg | ...] (default "svg")
  -graphviz
        Use Graphviz's dot program to render images.
  -group string
        Grouping functions by packages and/or types [pkg, type] (separated by comma) (default "pkg")
  -http string
        HTTP service address. (default ":7878")
  -ignore string
        Ignore package paths containing given prefixes (separated by comma)
  -include string
        Include package paths with given prefixes (separated by comma)
  -limit string
        Limit package paths to given prefixes (separated by comma)
  -minlen uint
        Minimum edge length (for wider output). (default 2)
  -nodesep float
        Minimum space between two adjacent nodes in the same rank (for taller output). (default 0.35)
  -nointer
        Omit calls to unexported functions.
  -nostd
        Omit calls to/from packages in standard library.
  -skipbrowser
        Skip opening browser.
  -tags build tags
        a list of build tags to consider satisfied during the build. For more information about build tags, see the description of buil
d constraints in the documentation for the go/build package
  -tests
        Include test code.
  -version
        Show version and exit.

依赖

• Go 1.17+
• Graphviz (可选，当工具指定了 -graphviz 时需要)

测试代码

package main
import (
	"log"
	"net"
)
func main() {
	// Part 1: create a listener
	l, err := net.Listen("tcp", ":8000")
	if err != nil {
		log.Fatalf("Error listener returned: %s", err)
	}
	defer l.Close()
	for {
		// Part 2: accept new connection
		c, err := l.Accept()
		if err != nil {
			log.Fatalf("Error to accept new connection: %s", err)
		}
		// Part 3: create a goroutine that reads and write back data
		go func() {
			log.Printf("TCP session open")
			defer c.Close()
			for {
				d := make([]byte, 1024)
				// Read from TCP buffer
				_, err := c.Read(d)
				if err != nil {
					log.Printf("Error reading TCP session: %s", err)
					break
				}
				log.Printf("reading data from client: %s\n", string(d))
				// write back data to TCP client
				_, err = c.Write(d)
				if err != nil {
					log.Printf("Error writing TCP session: %s", err)
					break
				}
			}
		}()
	}
}

在linux上可以正常运行，windows上会报错

> go-callvis main67.go
2022/09/21 15:28:50 http serving at http://localhost:7878

go-callvis 默认将代码调用关系存储成 svg 格式的图形。

在浏览器中访问 http://localhost:7878

点击上面的 log 模块，将会进入 log 模块的代码调用交互图中

它主要是作用是清晰的列出了包与包之间的依赖以及调用关系，用来理解项目的大致架构。