blob: a38f371d0f51b651df832c4162244759d23f5aa5 [file] [log] [blame]
// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package configstore abstracts interaction with the telemetry config server.
// Telemetry config (golang.org/x/telemetry/config) is distributed as a go
// module containing go.mod and config.json. Programs that upload collected
// counters download the latest config using `go mod download`. This provides
// verification of downloaded configuration and cacheability.
package configstore
import (
"bytes"
"encoding/json"
"fmt"
"os"
"os/exec"
"path/filepath"
"golang.org/x/telemetry/internal/telemetry"
)
const (
ModulePath = "golang.org/x/telemetry/config"
configFileName = "config.json"
)
// needNoConsole is used on windows to set the windows.CREATE_NO_WINDOW
// creation flag.
var needNoConsole = func(cmd *exec.Cmd) {}
// Download fetches the requested telemetry UploadConfig using "go mod
// download". If envOverlay is provided, it is appended to the environment used
// for invoking the go command.
//
// The second result is the canonical version of the requested configuration.
func Download(version string, envOverlay []string) (*telemetry.UploadConfig, string, error) {
if version == "" {
version = "latest"
}
modVer := ModulePath + "@" + version
var stdout, stderr bytes.Buffer
cmd := exec.Command("go", "mod", "download", "-json", modVer)
needNoConsole(cmd)
cmd.Env = append(os.Environ(), envOverlay...)
cmd.Stdout = &stdout
cmd.Stderr = &stderr
if err := cmd.Run(); err != nil {
var info struct {
Error string
}
if err := json.Unmarshal(stdout.Bytes(), &info); err == nil && info.Error != "" {
return nil, "", fmt.Errorf("failed to download config module: %v", info.Error)
}
return nil, "", fmt.Errorf("failed to download config module: %w\n%s", err, &stderr)
}
var info struct {
Dir string
Version string
Error string
}
if err := json.Unmarshal(stdout.Bytes(), &info); err != nil || info.Dir == "" {
return nil, "", fmt.Errorf("failed to download config module (invalid JSON): %w", err)
}
data, err := os.ReadFile(filepath.Join(info.Dir, configFileName))
if err != nil {
return nil, "", fmt.Errorf("invalid config module: %w", err)
}
cfg := new(telemetry.UploadConfig)
if err := json.Unmarshal(data, cfg); err != nil {
return nil, "", fmt.Errorf("invalid config: %w", err)
}
return cfg, info.Version, nil
}