packer-cn/packer/core.go

311 lines
7.8 KiB
Go

package packer
import (
"fmt"
"sort"
"github.com/hashicorp/go-multierror"
"github.com/hashicorp/go-version"
"github.com/mitchellh/packer/template"
"github.com/mitchellh/packer/template/interpolate"
)
// Core is the main executor of Packer. If Packer is being used as a
// library, this is the struct you'll want to instantiate to get anything done.
type Core struct {
Template *template.Template
components ComponentFinder
variables map[string]string
builds map[string]*template.Builder
version string
}
// CoreConfig is the structure for initializing a new Core. Once a CoreConfig
// is used to initialize a Core, it shouldn't be re-used or modified again.
type CoreConfig struct {
Components ComponentFinder
Template *template.Template
Variables map[string]string
Version string
}
// The function type used to lookup Builder implementations.
type BuilderFunc func(name string) (Builder, error)
// The function type used to lookup Hook implementations.
type HookFunc func(name string) (Hook, error)
// The function type used to lookup PostProcessor implementations.
type PostProcessorFunc func(name string) (PostProcessor, error)
// The function type used to lookup Provisioner implementations.
type ProvisionerFunc func(name string) (Provisioner, error)
// ComponentFinder is a struct that contains the various function
// pointers necessary to look up components of Packer such as builders,
// commands, etc.
type ComponentFinder struct {
Builder BuilderFunc
Hook HookFunc
PostProcessor PostProcessorFunc
Provisioner ProvisionerFunc
}
// NewCore creates a new Core.
func NewCore(c *CoreConfig) (*Core, error) {
result := &Core{
Template: c.Template,
components: c.Components,
variables: c.Variables,
version: c.Version,
}
if err := result.validate(); err != nil {
return nil, err
}
if err := result.init(); err != nil {
return nil, err
}
// Go through and interpolate all the build names. We shuld be able
// to do this at this point with the variables.
result.builds = make(map[string]*template.Builder)
for _, b := range c.Template.Builders {
v, err := interpolate.Render(b.Name, result.Context())
if err != nil {
return nil, fmt.Errorf(
"Error interpolating builder '%s': %s",
b.Name, err)
}
result.builds[v] = b
}
return result, nil
}
// BuildNames returns the builds that are available in this configured core.
func (c *Core) BuildNames() []string {
r := make([]string, 0, len(c.builds))
for n, _ := range c.builds {
r = append(r, n)
}
sort.Strings(r)
return r
}
// Build returns the Build object for the given name.
func (c *Core) Build(n string) (Build, error) {
// Setup the builder
configBuilder, ok := c.builds[n]
if !ok {
return nil, fmt.Errorf("no such build found: %s", n)
}
builder, err := c.components.Builder(configBuilder.Type)
if err != nil {
return nil, fmt.Errorf(
"error initializing builder '%s': %s",
configBuilder.Type, err)
}
if builder == nil {
return nil, fmt.Errorf(
"builder type not found: %s", configBuilder.Type)
}
// rawName is the uninterpolated name that we use for various lookups
rawName := configBuilder.Name
// Setup the provisioners for this build
provisioners := make([]coreBuildProvisioner, 0, len(c.Template.Provisioners))
for _, rawP := range c.Template.Provisioners {
// If we're skipping this, then ignore it
if rawP.Skip(rawName) {
continue
}
// Get the provisioner
provisioner, err := c.components.Provisioner(rawP.Type)
if err != nil {
return nil, fmt.Errorf(
"error initializing provisioner '%s': %s",
rawP.Type, err)
}
if provisioner == nil {
return nil, fmt.Errorf(
"provisioner type not found: %s", rawP.Type)
}
// Get the configuration
config := make([]interface{}, 1, 2)
config[0] = rawP.Config
if rawP.Override != nil {
if override, ok := rawP.Override[rawName]; ok {
config = append(config, override)
}
}
// If we're pausing, we wrap the provisioner in a special pauser.
if rawP.PauseBefore > 0 {
provisioner = &PausedProvisioner{
PauseBefore: rawP.PauseBefore,
Provisioner: provisioner,
}
}
provisioners = append(provisioners, coreBuildProvisioner{
provisioner: provisioner,
config: config,
})
}
// Setup the post-processors
postProcessors := make([][]coreBuildPostProcessor, 0, len(c.Template.PostProcessors))
for _, rawPs := range c.Template.PostProcessors {
current := make([]coreBuildPostProcessor, 0, len(rawPs))
for _, rawP := range rawPs {
// If we skip, ignore
if rawP.Skip(rawName) {
continue
}
// Get the post-processor
postProcessor, err := c.components.PostProcessor(rawP.Type)
if err != nil {
return nil, fmt.Errorf(
"error initializing post-processor '%s': %s",
rawP.Type, err)
}
if postProcessor == nil {
return nil, fmt.Errorf(
"post-processor type not found: %s", rawP.Type)
}
current = append(current, coreBuildPostProcessor{
processor: postProcessor,
processorType: rawP.Type,
config: rawP.Config,
keepInputArtifact: rawP.KeepInputArtifact,
})
}
// If we have no post-processors in this chain, just continue.
if len(current) == 0 {
continue
}
postProcessors = append(postProcessors, current)
}
// TODO hooks one day
return &coreBuild{
name: n,
builder: builder,
builderConfig: configBuilder.Config,
builderType: configBuilder.Type,
postProcessors: postProcessors,
provisioners: provisioners,
templatePath: c.Template.Path,
variables: c.variables,
}, nil
}
// Context returns an interpolation context.
func (c *Core) Context() *interpolate.Context {
return &interpolate.Context{
TemplatePath: c.Template.Path,
UserVariables: c.variables,
}
}
// validate does a full validation of the template.
//
// This will automatically call template.validate() in addition to doing
// richer semantic checks around variables and so on.
func (c *Core) validate() error {
// First validate the template in general, we can't do anything else
// unless the template itself is valid.
if err := c.Template.Validate(); err != nil {
return err
}
// Validate the minimum version is satisfied
if c.Template.MinVersion != "" {
versionActual, err := version.NewVersion(c.version)
if err != nil {
// This shouldn't happen since we set it via the compiler
panic(err)
}
versionMin, err := version.NewVersion(c.Template.MinVersion)
if err != nil {
return fmt.Errorf(
"min_version is invalid: %s", err)
}
if versionActual.LessThan(versionMin) {
return fmt.Errorf(
"This template requires Packer version %s or higher; using %s",
versionMin,
versionActual)
}
}
// Validate variables are set
var err error
for n, v := range c.Template.Variables {
if v.Required {
if _, ok := c.variables[n]; !ok {
err = multierror.Append(err, fmt.Errorf(
"required variable not set: %s", n))
}
}
}
// TODO: validate all builders exist
// TODO: ^^ provisioner
// TODO: ^^ post-processor
return err
}
func (c *Core) init() error {
if c.variables == nil {
c.variables = make(map[string]string)
}
// Go through the variables and interpolate the environment variables
ctx := c.Context()
ctx.EnableEnv = true
ctx.UserVariables = nil
for k, v := range c.Template.Variables {
// Ignore variables that are required
if v.Required {
continue
}
// Ignore variables that have a value
if _, ok := c.variables[k]; ok {
continue
}
// Interpolate the default
def, err := interpolate.Render(v.Default, ctx)
if err != nil {
return fmt.Errorf(
"error interpolating default value for '%s': %s",
k, err)
}
c.variables[k] = def
}
// Interpolate the push configuration
if _, err := interpolate.RenderInterface(&c.Template.Push, c.Context()); err != nil {
return fmt.Errorf("Error interpolating 'push': %s", err)
}
return nil
}