一款好用的 Go 調用鏈可視化工具

作者：機器鈴砍菜刀 2022-08-15 08:02:09

開發前端

go-callvis 工具將 Go 程序函數調用關系通過圖形可視化出來，它能幫助開發人員更好地梳理程序脈絡。且 go-callvis 的使用非常簡單，可以開箱即用。

在接手他人代碼或調研一些開源項目時，如果能夠理清其中的代碼調用鏈路，這將加速我們對實現的理解。

本文介紹一款工具 go-callvis，它能夠將 Go 代碼的調用關系可視化出來，并提供了可交互式的 web 服務。

go-callvis 使用

依賴

Go 1.17+
Graphviz (可選，當工具指定了 ??-graphviz?? 時需要)

工具安裝

go get -u github.com/ofabry/go-callvis
# or
git clone https://github.com/ofabry/go-callvis.git
cd go-callvis && make install

示例

package main

import (

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
    }
   }
  }()
 }
}

以上是一個簡單的TCP服務端代碼，通過 go-callvis 工具，可將其代碼調用關系梳理出來。

$ go-callvis main.go
2022/08/14 21:23:03 http serving at http://localhost:7878
2022/08/14 21:23:03 converting dot to svg..
2022/08/14 21:23:03 serving file: /var/folders/xk/gn46n46d503dsztbc6_9qb2h0000gn/T/go-callvis_export.svg

go-callvis 默認將代碼調用關系存儲成 svg 格式的圖形，并會在 http://localhost:7878 服務上進行展示。

在?瀏覽器界面上，如果點擊 log 單元，將會進入 log 模塊的代碼調用交互圖中。

使用參數

go-callvis 默認以 main 作為鏈路起點進行分析，因此 package 需要為 main 包。

go-callvis [flags] package

如果不想從 main 方法開始，那么需要使用 -tests 參數，并且在 yourpackage 下創建單元測試，在測試中調用你想要的起始點方法。

go-callvis -tests yourpackage

詳細使用說明可通過執行 go-callvis 命令查看

$ 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:

  -algo string
     The algorithm used to construct the call graph. Possible values inlcude: "static", "cha", "rta", "pointer" (default "pointer")
  -cacheDir string
     Enable caching to avoid unnecessary re-rendering, you can force rendering by adding 'refresh=true' to the URL query or emptying the cache directory
  -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)
  -nodeshape string
     graph node shape (see graphvis manpage for valid values) (default "box")
  -nodestyle string
     graph node style (see graphvis manpage for valid values) (default "filled,rounded")
  -nointer
     Omit calls to unexported functions.
  -nostd
     Omit calls to/from packages in standard library.
  -rankdir string
     Direction of graph layout [LR | RL | TB | BT] (default "LR")
  -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 build constraints in the documentation for the go/build package
  -tests
     Include test code.
  -version
     Show version and exit.
[slp@slpdeMacBook-Pro:] ~/repo/MongoShake/cmd/collector $ go-callvis --help
Usage of go-callvis:
  -algo string
     The algorithm used to construct the call graph. Possible values inlcude: "static", "cha", "rta", "pointer" (default "pointer")
  -cacheDir string
     Enable caching to avoid unnecessary re-rendering, you can force rendering by adding 'refresh=true' to the URL query or emptying the cache directory
  -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)
  -nodeshape string
     graph node shape (see graphvis manpage for valid values) (default "box")
  -nodestyle string
     graph node style (see graphvis manpage for valid values) (default "filled,rounded")
  -nointer
     Omit calls to unexported functions.
  -nostd
     Omit calls to/from packages in standard library.
  -rankdir string
     Direction of graph layout [LR | RL | TB | BT] (default "LR")
  -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 build constraints in the documentation for the go/build package
  -tests
     Include test code.
  -version
     Show version and exit.

每個參數都有對應的說明，無需詳細介紹。

有幾個比較有用的參數可以注意：nostd?用以忽略標準庫的調用；group?用以對函數分類；include?、limit?、ignore參數則用以控制過濾或保留調用關系。

總結

go-callvis 工具將 Go 程序函數調用關系通過圖形可視化出來，它能幫助開發人員更好地梳理程序脈絡。且 go-callvis 的使用非常簡單，可以開箱即用。

之后同學們在接觸復雜項目時，不妨用 go-callvis 試試看。?

責任編輯：武曉燕來源： Golang技術分享

Go 程序函數