src

Go monorepo.
git clone git://code.dwrz.net/src
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download.go (2690B)

      1 // Copyright 2023 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 configstore abstracts interaction with the telemetry config server.
      6 // Telemetry config (golang.org/x/telemetry/config) is distributed as a go
      7 // module containing go.mod and config.json. Programs that upload collected
      8 // counters download the latest config using `go mod download`. This provides
      9 // verification of downloaded configuration and cacheability.
     10 package configstore
     11 
     12 import (
     13 	"bytes"
     14 	"encoding/json"
     15 	"fmt"
     16 	"os"
     17 	"os/exec"
     18 	"path/filepath"
     19 	"sync/atomic"
     20 
     21 	"golang.org/x/telemetry/internal/telemetry"
     22 )
     23 
     24 const (
     25 	ModulePath     = "golang.org/x/telemetry/config"
     26 	configFileName = "config.json"
     27 )
     28 
     29 // needNoConsole is used on windows to set the windows.CREATE_NO_WINDOW
     30 // creation flag.
     31 var needNoConsole = func(cmd *exec.Cmd) {}
     32 
     33 var downloads int64
     34 
     35 // Downloads reports, for testing purposes, the number of times [Download] has
     36 // been called.
     37 func Downloads() int64 {
     38 	return atomic.LoadInt64(&downloads)
     39 }
     40 
     41 // Download fetches the requested telemetry UploadConfig using "go mod
     42 // download". If envOverlay is provided, it is appended to the environment used
     43 // for invoking the go command.
     44 //
     45 // The second result is the canonical version of the requested configuration.
     46 func Download(version string, envOverlay []string) (*telemetry.UploadConfig, string, error) {
     47 	atomic.AddInt64(&downloads, 1)
     48 
     49 	if version == "" {
     50 		version = "latest"
     51 	}
     52 	modVer := ModulePath + "@" + version
     53 	var stdout, stderr bytes.Buffer
     54 	cmd := exec.Command("go", "mod", "download", "-json", modVer)
     55 	needNoConsole(cmd)
     56 	cmd.Env = append(os.Environ(), envOverlay...)
     57 	cmd.Stdout = &stdout
     58 	cmd.Stderr = &stderr
     59 	if err := cmd.Run(); err != nil {
     60 		var info struct {
     61 			Error string
     62 		}
     63 		if err := json.Unmarshal(stdout.Bytes(), &info); err == nil && info.Error != "" {
     64 			return nil, "", fmt.Errorf("failed to download config module: %v", info.Error)
     65 		}
     66 		return nil, "", fmt.Errorf("failed to download config module: %w\n%s", err, &stderr)
     67 	}
     68 
     69 	var info struct {
     70 		Dir     string
     71 		Version string
     72 		Error   string
     73 	}
     74 	if err := json.Unmarshal(stdout.Bytes(), &info); err != nil || info.Dir == "" {
     75 		return nil, "", fmt.Errorf("failed to download config module (invalid JSON): %w", err)
     76 	}
     77 	data, err := os.ReadFile(filepath.Join(info.Dir, configFileName))
     78 	if err != nil {
     79 		return nil, "", fmt.Errorf("invalid config module: %w", err)
     80 	}
     81 	cfg := new(telemetry.UploadConfig)
     82 	if err := json.Unmarshal(data, cfg); err != nil {
     83 		return nil, "", fmt.Errorf("invalid config: %w", err)
     84 	}
     85 	return cfg, info.Version, nil
     86 }