packer-cn/config.go

215 lines
5.4 KiB
Go

package main
import (
"encoding/json"
"io"
"log"
"os/exec"
"path/filepath"
"strings"
"github.com/mitchellh/osext"
"github.com/mitchellh/packer/packer"
"github.com/mitchellh/packer/packer/plugin"
)
type config struct {
PluginMinPort uint
PluginMaxPort uint
Builders map[string]string
Commands map[string]string
PostProcessors map[string]string `json:"post-processors"`
Provisioners map[string]string
}
// Decodes configuration in JSON format from the given io.Reader into
// the config object pointed to.
func decodeConfig(r io.Reader, c *config) error {
decoder := json.NewDecoder(r)
return decoder.Decode(c)
}
// Discover discovers plugins.
//
// This looks in the directory of the executable and the CWD, in that
// order for priority.
func (c *config) Discover() error {
// Look in the cwd.
if err := c.discover("."); err != nil {
return err
}
// Next, look in the same directory as the executable. Any conflicts
// will overwrite those found in our current directory.
exePath, err := osext.Executable()
if err != nil {
log.Printf("[ERR] Error loading exe directory: %s", err)
} else {
if err := c.discover(filepath.Dir(exePath)); err != nil {
return err
}
}
return nil
}
// Returns an array of defined command names.
func (c *config) CommandNames() (result []string) {
result = make([]string, 0, len(c.Commands))
for name := range c.Commands {
result = append(result, name)
}
return
}
// This is a proper packer.BuilderFunc that can be used to load packer.Builder
// implementations from the defined plugins.
func (c *config) LoadBuilder(name string) (packer.Builder, error) {
log.Printf("Loading builder: %s\n", name)
bin, ok := c.Builders[name]
if !ok {
log.Printf("Builder not found: %s\n", name)
return nil, nil
}
return c.pluginClient(bin).Builder()
}
// This is a proper packer.CommandFunc that can be used to load packer.Command
// implementations from the defined plugins.
func (c *config) LoadCommand(name string) (packer.Command, error) {
log.Printf("Loading command: %s\n", name)
bin, ok := c.Commands[name]
if !ok {
log.Printf("Command not found: %s\n", name)
return nil, nil
}
return c.pluginClient(bin).Command()
}
// This is a proper implementation of packer.HookFunc that can be used
// to load packer.Hook implementations from the defined plugins.
func (c *config) LoadHook(name string) (packer.Hook, error) {
log.Printf("Loading hook: %s\n", name)
return c.pluginClient(name).Hook()
}
// This is a proper packer.PostProcessorFunc that can be used to load
// packer.PostProcessor implementations from defined plugins.
func (c *config) LoadPostProcessor(name string) (packer.PostProcessor, error) {
log.Printf("Loading post-processor: %s", name)
bin, ok := c.PostProcessors[name]
if !ok {
log.Printf("Post-processor not found: %s", name)
return nil, nil
}
return c.pluginClient(bin).PostProcessor()
}
// This is a proper packer.ProvisionerFunc that can be used to load
// packer.Provisioner implementations from defined plugins.
func (c *config) LoadProvisioner(name string) (packer.Provisioner, error) {
log.Printf("Loading provisioner: %s\n", name)
bin, ok := c.Provisioners[name]
if !ok {
log.Printf("Provisioner not found: %s\n", name)
return nil, nil
}
return c.pluginClient(bin).Provisioner()
}
func (c *config) discover(path string) error {
var err error
err = c.discoverSingle(
filepath.Join(path, "packer-builder-*"), &c.Builders)
if err != nil {
return err
}
err = c.discoverSingle(
filepath.Join(path, "packer-command-*"), &c.Commands)
if err != nil {
return err
}
err = c.discoverSingle(
filepath.Join(path, "packer-post-processor-*"), &c.PostProcessors)
if err != nil {
return err
}
err = c.discoverSingle(
filepath.Join(path, "packer-provisioner-*"), &c.Provisioners)
if err != nil {
return err
}
return nil
}
func (c *config) discoverSingle(glob string, m *map[string]string) error {
matches, err := filepath.Glob(glob)
if err != nil {
return err
}
if *m == nil {
*m = make(map[string]string)
}
prefix := filepath.Base(glob)
prefix = prefix[:strings.Index(prefix, "*")]
for _, match := range matches {
file := filepath.Base(match)
// If the filename has a ".", trim up to there
if idx := strings.Index(file, "."); idx >= 0 {
file = file[:idx]
}
// Look for foo-bar-baz. The plugin name is "baz"
plugin := file[len(prefix):]
log.Printf("[DEBUG] Discoverd plugin: %s = %s", plugin, match)
(*m)[plugin] = match
}
return nil
}
func (c *config) pluginClient(path string) *plugin.Client {
originalPath := path
// First attempt to find the executable by consulting the PATH.
path, err := exec.LookPath(path)
if err != nil {
// If that doesn't work, look for it in the same directory
// as the `packer` executable (us).
log.Printf("Plugin could not be found. Checking same directory as executable.")
exePath, err := osext.Executable()
if err != nil {
log.Printf("Couldn't get current exe path: %s", err)
} else {
log.Printf("Current exe path: %s", exePath)
path = filepath.Join(filepath.Dir(exePath), filepath.Base(originalPath))
}
}
// If everything failed, just use the original path and let the error
// bubble through.
if path == "" {
path = originalPath
}
log.Printf("Creating plugin client for path: %s", path)
var config plugin.ClientConfig
config.Cmd = exec.Command(path)
config.Managed = true
config.MinPort = c.PluginMinPort
config.MaxPort = c.PluginMaxPort
return plugin.NewClient(&config)
}