packer-cn/packer.go

234 lines
5.7 KiB
Go

// This is the main package for the `packer` application.
package main
import (
"bytes"
"fmt"
"github.com/mitchellh/packer/packer"
"github.com/mitchellh/packer/packer/plugin"
"github.com/mitchellh/panicwrap"
"io"
"io/ioutil"
"log"
"os"
"path/filepath"
"runtime"
)
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 {
// If there is no explicit number of Go threads to use, then set it
if os.Getenv("GOMAXPROCS") == "" {
runtime.GOMAXPROCS(runtime.NumCPU())
}
// 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
}
// We also 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()
// Reset the log variables to minimize work in the subprocess
os.Setenv("PACKER_LOG", "")
os.Setenv("PACKER_LOG_FILE", "")
// Create the configuration for panicwrap and wrap our executable
wrapConfig := &panicwrap.WrapConfig{
Handler: panicHandler(logTempFile),
Writer: io.MultiWriter(logTempFile, logWriter),
}
exitStatus, err := panicwrap.Wrap(wrapConfig)
if err != nil {
fmt.Fprintf(os.Stderr, "Couldn't start Packer: %s", err)
return 1
}
if exitStatus >= 0 {
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()
return wrappedMain()
}
// wrappedMain is called only when we're wrapped by panicwrap and
// returns the exit status to exit with.
func wrappedMain() int {
log.SetOutput(os.Stderr)
log.Printf(
"Packer Version: %s %s %s",
packer.Version, packer.VersionPrerelease, packer.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)
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
}
if err := os.MkdirAll(cacheDir, 0755); 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()
// Create the environment configuration
envConfig := packer.DefaultEnvironmentConfig()
envConfig.Cache = cache
envConfig.Commands = config.CommandNames()
envConfig.Components.Builder = config.LoadBuilder
envConfig.Components.Command = config.LoadCommand
envConfig.Components.Hook = config.LoadHook
envConfig.Components.PostProcessor = config.LoadPostProcessor
envConfig.Components.Provisioner = config.LoadProvisioner
if machineReadable {
envConfig.Ui = &packer.MachineReadableUi{
Writer: os.Stdout,
}
}
env, err := packer.NewEnvironment(envConfig)
if err != nil {
fmt.Fprintf(os.Stderr, "Packer initialization error: \n\n%s\n", err)
return 1
}
setupSignalHandlers(env)
exitCode, err := env.Cli(args)
if err != nil {
fmt.Fprintf(os.Stderr, "Error executing CLI: %s\n", err.Error())
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
if err := decodeConfig(bytes.NewBufferString(defaultConfig), &config); err != nil {
return nil, err
}
mustExist := true
configFilePath := os.Getenv("PACKER_CONFIG")
if configFilePath == "" {
var err error
configFilePath, err = configFile()
mustExist = false
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
}
if mustExist {
return nil, err
}
log.Println("File doesn't exist, but doesn't need to. Ignoring.")
return &config, nil
}
defer f.Close()
if err := decodeConfig(f, &config); err != nil {
return nil, err
}
return &config, nil
}
// logOutput determines where we should send logs (if anywhere).
func logOutput() (logOutput io.Writer, err error) {
logOutput = ioutil.Discard
if os.Getenv("PACKER_LOG") != "" {
logOutput = os.Stderr
if logPath := os.Getenv("PACKER_LOG_PATH"); logPath != "" {
var err error
logOutput, err = os.Create(logPath)
if err != nil {
return nil, err
}
}
}
return
}