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Source file src/pkg/cmd/go/internal/modcmd/download.go

     1	// Copyright 2018 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	package modcmd
     6	
     7	import (
     8		"cmd/go/internal/cfg"
     9		"encoding/json"
    10		"os"
    11	
    12		"cmd/go/internal/base"
    13		"cmd/go/internal/modfetch"
    14		"cmd/go/internal/modload"
    15		"cmd/go/internal/module"
    16		"cmd/go/internal/par"
    17	)
    18	
    19	var cmdDownload = &base.Command{
    20		UsageLine: "go mod download [-json] [modules]",
    21		Short:     "download modules to local cache",
    22		Long: `
    23	Download downloads the named modules, which can be module patterns selecting
    24	dependencies of the main module or module queries of the form path@version.
    25	With no arguments, download applies to all dependencies of the main module.
    26	
    27	The go command will automatically download modules as needed during ordinary
    28	execution. The "go mod download" command is useful mainly for pre-filling
    29	the local cache or to compute the answers for a Go module proxy.
    30	
    31	By default, download reports errors to standard error but is otherwise silent.
    32	The -json flag causes download to print a sequence of JSON objects
    33	to standard output, describing each downloaded module (or failure),
    34	corresponding to this Go struct:
    35	
    36	    type Module struct {
    37	        Path     string // module path
    38	        Version  string // module version
    39	        Error    string // error loading module
    40	        Info     string // absolute path to cached .info file
    41	        GoMod    string // absolute path to cached .mod file
    42	        Zip      string // absolute path to cached .zip file
    43	        Dir      string // absolute path to cached source root directory
    44	        Sum      string // checksum for path, version (as in go.sum)
    45	        GoModSum string // checksum for go.mod (as in go.sum)
    46	    }
    47	
    48	See 'go help modules' for more about module queries.
    49		`,
    50	}
    51	
    52	var downloadJSON = cmdDownload.Flag.Bool("json", false, "")
    53	
    54	func init() {
    55		cmdDownload.Run = runDownload // break init cycle
    56	}
    57	
    58	type moduleJSON struct {
    59		Path     string `json:",omitempty"`
    60		Version  string `json:",omitempty"`
    61		Error    string `json:",omitempty"`
    62		Info     string `json:",omitempty"`
    63		GoMod    string `json:",omitempty"`
    64		Zip      string `json:",omitempty"`
    65		Dir      string `json:",omitempty"`
    66		Sum      string `json:",omitempty"`
    67		GoModSum string `json:",omitempty"`
    68	}
    69	
    70	func runDownload(cmd *base.Command, args []string) {
    71		// Check whether modules are enabled and whether we're in a module.
    72		if cfg.Getenv("GO111MODULE") == "off" {
    73			base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
    74		}
    75		if !modload.HasModRoot() && len(args) == 0 {
    76			base.Fatalf("go mod download: no modules specified (see 'go help mod download')")
    77		}
    78		if len(args) == 0 {
    79			args = []string{"all"}
    80		}
    81	
    82		var mods []*moduleJSON
    83		var work par.Work
    84		listU := false
    85		listVersions := false
    86		for _, info := range modload.ListModules(args, listU, listVersions) {
    87			if info.Replace != nil {
    88				info = info.Replace
    89			}
    90			if info.Version == "" && info.Error == nil {
    91				// main module
    92				continue
    93			}
    94			m := &moduleJSON{
    95				Path:    info.Path,
    96				Version: info.Version,
    97			}
    98			mods = append(mods, m)
    99			if info.Error != nil {
   100				m.Error = info.Error.Err
   101				continue
   102			}
   103			work.Add(m)
   104		}
   105	
   106		work.Do(10, func(item interface{}) {
   107			m := item.(*moduleJSON)
   108			var err error
   109			m.Info, err = modfetch.InfoFile(m.Path, m.Version)
   110			if err != nil {
   111				m.Error = err.Error()
   112				return
   113			}
   114			m.GoMod, err = modfetch.GoModFile(m.Path, m.Version)
   115			if err != nil {
   116				m.Error = err.Error()
   117				return
   118			}
   119			m.GoModSum, err = modfetch.GoModSum(m.Path, m.Version)
   120			if err != nil {
   121				m.Error = err.Error()
   122				return
   123			}
   124			mod := module.Version{Path: m.Path, Version: m.Version}
   125			m.Zip, err = modfetch.DownloadZip(mod)
   126			if err != nil {
   127				m.Error = err.Error()
   128				return
   129			}
   130			m.Sum = modfetch.Sum(mod)
   131			m.Dir, err = modfetch.Download(mod)
   132			if err != nil {
   133				m.Error = err.Error()
   134				return
   135			}
   136		})
   137	
   138		if *downloadJSON {
   139			for _, m := range mods {
   140				b, err := json.MarshalIndent(m, "", "\t")
   141				if err != nil {
   142					base.Fatalf("%v", err)
   143				}
   144				os.Stdout.Write(append(b, '\n'))
   145				if m.Error != "" {
   146					base.SetExitStatus(1)
   147				}
   148			}
   149		} else {
   150			for _, m := range mods {
   151				if m.Error != "" {
   152					base.Errorf("%s", m.Error)
   153				}
   154			}
   155			base.ExitIfErrors()
   156		}
   157	}
   158	

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