packer-cn/main.go

294 lines
6.9 KiB
Go

// This is the main package for the `packer` application.
package main
import (
"fmt"
"io"
"io/ioutil"
"log"
"os"
"path/filepath"
"runtime"
"sync"
"github.com/mitchellh/cli"
"github.com/mitchellh/packer/command"
"github.com/mitchellh/packer/packer"
"github.com/mitchellh/packer/packer/plugin"
"github.com/mitchellh/panicwrap"
"github.com/mitchellh/prefixedio"
)
func main() {
// Call realMain instead of doing the work here so we can use
// `defer` statements within the function and have them work properly.
// (defers aren't called with os.Exit)
os.Exit(realMain())
}
// realMain is executed from main and returns the exit status to exit with.
func realMain() int {
var wrapConfig panicwrap.WrapConfig
if !panicwrap.Wrapped(&wrapConfig) {
// Determine where logs should go in general (requested by the user)
logWriter, err := logOutput()
if err != nil {
fmt.Fprintf(os.Stderr, "Couldn't setup log output: %s", err)
return 1
}
if logWriter == nil {
logWriter = ioutil.Discard
}
// We always send logs to a temporary file that we use in case
// there is a panic. Otherwise, we delete it.
logTempFile, err := ioutil.TempFile("", "packer-log")
if err != nil {
fmt.Fprintf(os.Stderr, "Couldn't setup logging tempfile: %s", err)
return 1
}
defer os.Remove(logTempFile.Name())
defer logTempFile.Close()
// Tell the logger to log to this file
os.Setenv(EnvLog, "")
os.Setenv(EnvLogFile, "")
// Setup the prefixed readers that send data properly to
// stdout/stderr.
doneCh := make(chan struct{})
outR, outW := io.Pipe()
go copyOutput(outR, doneCh)
// Create the configuration for panicwrap and wrap our executable
wrapConfig.Handler = panicHandler(logTempFile)
wrapConfig.Writer = io.MultiWriter(logTempFile, logWriter)
wrapConfig.Stdout = outW
exitStatus, err := panicwrap.Wrap(&wrapConfig)
if err != nil {
fmt.Fprintf(os.Stderr, "Couldn't start Packer: %s", err)
return 1
}
// If >= 0, we're the parent, so just exit
if exitStatus >= 0 {
// Close the stdout writer so that our copy process can finish
outW.Close()
// Wait for the output copying to finish
<-doneCh
return exitStatus
}
// We're the child, so just close the tempfile we made in order to
// save file handles since the tempfile is only used by the parent.
logTempFile.Close()
}
// Call the real main
return wrappedMain()
}
// wrappedMain is called only when we're wrapped by panicwrap and
// returns the exit status to exit with.
func wrappedMain() int {
// If there is no explicit number of Go threads to use, then set it
if os.Getenv("GOMAXPROCS") == "" {
runtime.GOMAXPROCS(runtime.NumCPU())
}
log.SetOutput(os.Stderr)
log.Printf(
"[INFO] Packer version: %s %s %s",
Version, VersionPrerelease, GitCommit)
log.Printf("Packer Target OS/Arch: %s %s", runtime.GOOS, runtime.GOARCH)
log.Printf("Built with Go Version: %s", runtime.Version())
// Prepare stdin for plugin usage by switching it to a pipe
setupStdin()
config, err := loadConfig()
if err != nil {
fmt.Fprintf(os.Stderr, "Error loading configuration: \n\n%s\n", err)
return 1
}
log.Printf("Packer config: %+v", config)
// Fire off the checkpoint.
go runCheckpoint(config)
cacheDir := os.Getenv("PACKER_CACHE_DIR")
if cacheDir == "" {
cacheDir = "packer_cache"
}
cacheDir, err = filepath.Abs(cacheDir)
if err != nil {
fmt.Fprintf(os.Stderr, "Error preparing cache directory: \n\n%s\n", err)
return 1
}
log.Printf("Setting cache directory: %s", cacheDir)
cache := &packer.FileCache{CacheDir: cacheDir}
// Determine if we're in machine-readable mode by mucking around with
// the arguments...
args, machineReadable := extractMachineReadable(os.Args[1:])
defer plugin.CleanupClients()
// Setup the UI if we're being machine-readable
var ui packer.Ui = &packer.BasicUi{
Reader: os.Stdin,
Writer: os.Stdout,
ErrorWriter: os.Stdout,
}
if machineReadable {
ui = &packer.MachineReadableUi{
Writer: os.Stdout,
}
// Set this so that we don't get colored output in our machine-
// readable UI.
if err := os.Setenv("PACKER_NO_COLOR", "1"); err != nil {
fmt.Fprintf(os.Stderr, "Packer failed to initialize UI: %s\n", err)
return 1
}
}
// Create the CLI meta
CommandMeta = &command.Meta{
CoreConfig: &packer.CoreConfig{
Components: packer.ComponentFinder{
Builder: config.LoadBuilder,
Hook: config.LoadHook,
PostProcessor: config.LoadPostProcessor,
Provisioner: config.LoadProvisioner,
},
},
Cache: cache,
Ui: ui,
}
//setupSignalHandlers(env)
cli := &cli.CLI{
Args: args,
Commands: Commands,
HelpFunc: cli.BasicHelpFunc("packer"),
HelpWriter: os.Stdout,
Version: Version,
}
exitCode, err := cli.Run()
if err != nil {
fmt.Fprintf(os.Stderr, "Error executing CLI: %s\n", err)
return 1
}
return exitCode
}
// extractMachineReadable checks the args for the machine readable
// flag and returns whether or not it is on. It modifies the args
// to remove this flag.
func extractMachineReadable(args []string) ([]string, bool) {
for i, arg := range args {
if arg == "-machine-readable" {
// We found it. Slice it out.
result := make([]string, len(args)-1)
copy(result, args[:i])
copy(result[i:], args[i+1:])
return result, true
}
}
return args, false
}
func loadConfig() (*config, error) {
var config config
config.PluginMinPort = 10000
config.PluginMaxPort = 25000
if err := config.Discover(); err != nil {
return nil, err
}
configFilePath := os.Getenv("PACKER_CONFIG")
if configFilePath == "" {
var err error
configFilePath, err = configFile()
if err != nil {
log.Printf("Error detecting default config file path: %s", err)
}
}
if configFilePath == "" {
return &config, nil
}
log.Printf("Attempting to open config file: %s", configFilePath)
f, err := os.Open(configFilePath)
if err != nil {
if !os.IsNotExist(err) {
return nil, err
}
log.Printf("[WARN] Config file doesn't exist: %s", configFilePath)
return &config, nil
}
defer f.Close()
if err := decodeConfig(f, &config); err != nil {
return nil, err
}
return &config, nil
}
// copyOutput uses output prefixes to determine whether data on stdout
// should go to stdout or stderr. This is due to panicwrap using stderr
// as the log and error channel.
func copyOutput(r io.Reader, doneCh chan<- struct{}) {
defer close(doneCh)
pr, err := prefixedio.NewReader(r)
if err != nil {
panic(err)
}
stderrR, err := pr.Prefix(ErrorPrefix)
if err != nil {
panic(err)
}
stdoutR, err := pr.Prefix(OutputPrefix)
if err != nil {
panic(err)
}
defaultR, err := pr.Prefix("")
if err != nil {
panic(err)
}
var wg sync.WaitGroup
wg.Add(3)
go func() {
defer wg.Done()
io.Copy(os.Stderr, stderrR)
}()
go func() {
defer wg.Done()
io.Copy(os.Stdout, stdoutR)
}()
go func() {
defer wg.Done()
io.Copy(os.Stdout, defaultR)
}()
wg.Wait()
}