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moby--moby/builder.go
Guillaume J. Charmes 4386edff0b Better varibale names
2013-05-06 16:01:00 -07:00

263 lines
6.8 KiB
Go

package docker
import (
"bufio"
"fmt"
"io"
"os"
"path"
"strings"
"time"
)
type Builder struct {
runtime *Runtime
repositories *TagStore
graph *Graph
}
func NewBuilder(runtime *Runtime) *Builder {
return &Builder{
runtime: runtime,
graph: runtime.graph,
repositories: runtime.repositories,
}
}
func (builder *Builder) Create(config *Config) (*Container, error) {
// Lookup image
img, err := builder.repositories.LookupImage(config.Image)
if err != nil {
return nil, err
}
// Generate id
id := GenerateId()
// Generate default hostname
// FIXME: the lxc template no longer needs to set a default hostname
if config.Hostname == "" {
config.Hostname = id[:12]
}
container := &Container{
// FIXME: we should generate the ID here instead of receiving it as an argument
Id: id,
Created: time.Now(),
Path: config.Cmd[0],
Args: config.Cmd[1:], //FIXME: de-duplicate from config
Config: config,
Image: img.Id, // Always use the resolved image id
NetworkSettings: &NetworkSettings{},
// FIXME: do we need to store this in the container?
SysInitPath: sysInitPath,
}
container.root = builder.runtime.containerRoot(container.Id)
// Step 1: create the container directory.
// This doubles as a barrier to avoid race conditions.
if err := os.Mkdir(container.root, 0700); err != nil {
return nil, err
}
// If custom dns exists, then create a resolv.conf for the container
if len(config.Dns) > 0 {
container.ResolvConfPath = path.Join(container.root, "resolv.conf")
f, err := os.Create(container.ResolvConfPath)
if err != nil {
return nil, err
}
defer f.Close()
for _, dns := range config.Dns {
if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
return nil, err
}
}
} else {
container.ResolvConfPath = "/etc/resolv.conf"
}
// Step 2: save the container json
if err := container.ToDisk(); err != nil {
return nil, err
}
// Step 3: register the container
if err := builder.runtime.Register(container); err != nil {
return nil, err
}
return container, nil
}
// Commit creates a new filesystem image from the current state of a container.
// The image can optionally be tagged into a repository
func (builder *Builder) Commit(container *Container, repository, tag, comment, author string) (*Image, error) {
// FIXME: freeze the container before copying it to avoid data corruption?
// FIXME: this shouldn't be in commands.
rwTar, err := container.ExportRw()
if err != nil {
return nil, err
}
// Create a new image from the container's base layers + a new layer from container changes
img, err := builder.graph.Create(rwTar, container, comment, author)
if err != nil {
return nil, err
}
// Register the image if needed
if repository != "" {
if err := builder.repositories.Set(repository, tag, img.Id, true); err != nil {
return img, err
}
}
return img, nil
}
func (builder *Builder) clearTmp(containers, images map[string]struct{}) {
for c := range containers {
tmp := builder.runtime.Get(c)
builder.runtime.Destroy(tmp)
Debugf("Removing container %s", c)
}
for i := range images {
builder.runtime.graph.Delete(i)
Debugf("Removing image %s", i)
}
}
func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, error) {
var (
image, base *Image
tmpContainers map[string]struct{} = make(map[string]struct{})
tmpImages map[string]struct{} = make(map[string]struct{})
)
defer builder.clearTmp(tmpContainers, tmpImages)
file := bufio.NewReader(dockerfile)
for {
line, err := file.ReadString('\n')
if err != nil {
if err == io.EOF {
break
}
return nil, err
}
line = strings.TrimSpace(line)
// Skip comments and empty line
if len(line) == 0 || line[0] == '#' {
continue
}
tmp := strings.SplitN(line, " ", 2)
if len(tmp) != 2 {
return nil, fmt.Errorf("Invalid Dockerfile format")
}
instruction := tmp[0]
arguments := tmp[1]
switch strings.ToLower(instruction) {
case "from":
fmt.Fprintf(stdout, "FROM %s\n", arguments)
image, err = builder.runtime.repositories.LookupImage(arguments)
if err != nil {
return nil, err
}
break
case "run":
fmt.Fprintf(stdout, "RUN %s\n", arguments)
if image == nil {
return nil, fmt.Errorf("Please provide a source image with `from` prior to run")
}
config, err := ParseRun([]string{image.Id, "/bin/sh", "-c", arguments}, nil, builder.runtime.capabilities)
if err != nil {
return nil, err
}
// Create the container and start it
c, err := builder.Create(config)
if err != nil {
return nil, err
}
if err := c.Start(); err != nil {
return nil, err
}
tmpContainers[c.Id] = struct{}{}
// Wait for it to finish
if result := c.Wait(); result != 0 {
return nil, fmt.Errorf("!!! '%s' return non-zero exit code '%d'. Aborting.", arguments, result)
}
// Commit the container
base, err = builder.Commit(c, "", "", "", "")
if err != nil {
return nil, err
}
tmpImages[base.Id] = struct{}{}
fmt.Fprintf(stdout, "===> %s\n", base.ShortId())
// use the base as the new image
image = base
break
case "insert":
if image == nil {
return nil, fmt.Errorf("Please provide a source image with `from` prior to copy")
}
tmp = strings.SplitN(arguments, " ", 2)
if len(tmp) != 2 {
return nil, fmt.Errorf("Invalid INSERT format")
}
sourceUrl := tmp[0]
destPath := tmp[1]
fmt.Fprintf(stdout, "COPY %s to %s in %s\n", sourceUrl, destPath, base.ShortId())
file, err := Download(sourceUrl, stdout)
if err != nil {
return nil, err
}
defer file.Body.Close()
config, err := ParseRun([]string{base.Id, "echo", "insert", sourceUrl, destPath}, nil, builder.runtime.capabilities)
if err != nil {
return nil, err
}
c, err := builder.Create(config)
if err != nil {
return nil, err
}
if err := c.Start(); err != nil {
return nil, err
}
// Wait for echo to finish
if result := c.Wait(); result != 0 {
return nil, fmt.Errorf("!!! '%s' return non-zero exit code '%d'. Aborting.", arguments, result)
}
if err := c.Inject(file.Body, destPath); err != nil {
return nil, err
}
base, err = builder.Commit(c, "", "", "", "")
if err != nil {
return nil, err
}
fmt.Fprintf(stdout, "===> %s\n", base.ShortId())
image = base
break
default:
fmt.Fprintf(stdout, "Skipping unknown instruction %s\n", instruction)
}
}
if base != nil {
// The build is successful, keep the temporary containers and images
for i := range tmpImages {
delete(tmpImages, i)
}
for i := range tmpContainers {
delete(tmpContainers, i)
}
fmt.Fprintf(stdout, "Build finished. image id: %s\n", base.ShortId())
} else {
fmt.Fprintf(stdout, "An error occured during the build\n")
}
return base, nil
}