go list

• 用法
• -f
• -m

用法

• 列举命名包，每行一个。不带参数时判断一个包是否存在工作空间，存在则输出包的导入路径
• 命令 go list [-f format] [-json] [-m] [list flags] [build flags] [packages]
  • 常用的参数是 -f 和 -json，用于控制输出格式
• go list cnet hash
• ... 通配符用于匹配包的导入路径中的任意子串
  • go list ... 枚举工作空间的所有包
  • go list ch3/... 指定子树中的所有包
  • go list ...xml.. 指定具体主题
• go list 获取每个包的完整元数据，提供各种用于对用户或其他工具可访问的格式

-f

• 使用包模板语法指定可选格式。默认输出等价于 -f '{{ImportPath}}'。-f 的值需要满足 text/template 中定义的语法
  • {{.S}} 代表根结构体的 S 字段的值。go list 对应的跟结构体就是指定的代码包所对应的的结构体
  • go list -f {{.GoFiles}} cnet/ctcp
  • go list -e -f {{.Error.Err}} cnet
  • go list -e -f 'The package {{.ImportPath}} is {{if .Incomplete}}incomplete!{{else}}complete.{{end}}' cnet

• 模板结构如下

  type Package struct {
    Dir           string   // directory containing package sources
    ImportPath    string   // import path of package in dir
    ImportComment string   // path in import comment on package statement
    Name          string   // package name
    Doc           string   // package documentation string
    Target        string   // install path
    Shlib         string   // the shared library that contains this package (only set when -linkshared)
    Goroot        bool     // is this package in the Go root?
    Standard      bool     // is this package part of the standard Go library?
    Stale         bool     // would 'go install' do anything for this package?
    StaleReason   string   // explanation for Stale==true
    Root          string   // Go root or Go path dir containing this package
    ConflictDir   string   // this directory shadows Dir in $GOPATH
    BinaryOnly    bool     // binary-only package (no longer supported)
    ForTest       string   // package is only for use in named test
    Export        string   // file containing export data (when using -export)
    Module        *Module  // info about package's containing module, if any (can be nil)
    Match         []string // command-line patterns matching this package
    DepOnly       bool     // package is only a dependency, not explicitly listed
  
    // Source files
    GoFiles         []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
    CgoFiles        []string // .go source files that import "C"
    CompiledGoFiles []string // .go files presented to compiler (when using -compiled)
    IgnoredGoFiles  []string // .go source files ignored due to build constraints
    CFiles          []string // .c source files
    CXXFiles        []string // .cc, .cxx and .cpp source files
    MFiles          []string // .m source files
    HFiles          []string // .h, .hh, .hpp and .hxx source files
    FFiles          []string // .f, .F, .for and .f90 Fortran source files
    SFiles          []string // .s source files
    SwigFiles       []string // .swig files
    SwigCXXFiles    []string // .swigcxx files
    SysoFiles       []string // .syso object files to add to archive
    TestGoFiles     []string // _test.go files in package
    XTestGoFiles    []string // _test.go files outside package
  
    // Cgo directives
    CgoCFLAGS    []string // cgo: flags for C compiler
    CgoCPPFLAGS  []string // cgo: flags for C preprocessor
    CgoCXXFLAGS  []string // cgo: flags for C++ compiler
    CgoFFLAGS    []string // cgo: flags for Fortran compiler
    CgoLDFLAGS   []string // cgo: flags for linker
    CgoPkgConfig []string // cgo: pkg-config names
  
    // Dependency information
    Imports      []string          // import paths used by this package
    ImportMap    map[string]string // map from source import to ImportPath (identity entries omitted)
    Deps         []string          // all (recursively) imported dependencies
    TestImports  []string          // imports from TestGoFiles
    XTestImports []string          // imports from XTestGoFiles
  
    // Error information
    Incomplete bool            // this package or a dependency has an error
    Error      *PackageError   // error loading package
    DepsErrors []*PackageError // errors loading dependencies
  }
  
  type PackageError struct {
    ImportStack   []string // shortest path from package named on command line to this one
    Pos           string   // position of error (if present, file:line:col)
    Err           string   // the error itself
  }
  

• 模板函数 join 调用 strings.Join

  • go list -f '{{join .Deps " "}}' strconv 输出 strconv 包的依赖过渡关系记录，空格分隔
  • go list -f '{{.ImportPath}} -> {{join .Imports " "}}' compress/... 输出标准库的 compress 子树中每个包的直接导入记录

• 模板函数 context 返回构建上下文，定义如下

  type Context struct {
    GOARCH        string   // target architecture
    GOOS          string   // target operating system
    GOROOT        string   // Go root
    GOPATH        string   // Go path
    CgoEnabled    bool     // whether cgo can be used
    UseAllFiles   bool     // use files regardless of +build lines, file names
    Compiler      string   // compiler to assume when computing target paths
    BuildTags     []string // build constraints to match in +build lines
    ReleaseTags   []string // releases the current release is compatible with
    InstallSuffix string   // suffix to use in the name of the install dir
  }
  

-m

• 默认输出模块路径、版本信息，如果有替换，输出替换信息
  • 如果有替换，即 Replace 不为 nil 时，下面的 Dir 设置的是 Replace.Dir
• 主模块是包含当前目录的模块。活动模块是主模块及其依赖模块。默认显示主模块
  • all 指定所有活动模块
• 和 -f 一起使用，指定模块模板

• 结构体 Module 有一个 String 方法，用于格式化输出行，因此默认输出等价于 -f {{.String}}

  type Module struct {
    Path      string       // module path
    Version   string       // module version
    Versions  []string     // available module versions (with -versions)
    Replace   *Module      // replaced by this module
    Time      *time.Time   // time version was created
    Update    *Module      // available update, if any (with -u)
    Main      bool         // is this the main module?
    Indirect  bool         // is this module only an indirect dependency of main module?
    Dir       string       // directory holding files for this module, if any
    GoMod     string       // path to go.mod file for this module, if any
    GoVersion string       // go version used in module
    Error     *ModuleError // error loading module
  }
  
  type ModuleError struct {
    Err string // the error itself
  }
  

• -u 增加了关于可以升级的信息：go list -m -u -json all

• -version 设置 Module.Version 域为模块已知的版本

• 模板函数 module 接收一个字符串参数(必须是一个模块路径或查询)，返回指定的模块对应的 Module 结构体