docker/builder.go

119 строки
3.1 KiB
Go

package docker
import (
"fmt"
"os"
"path"
"time"
)
type Builder struct {
runtime *Runtime
repositories *TagStore
graph *Graph
config *Config
image *Image
}
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
}
if img.Config != nil {
MergeConfig(config, img.Config)
}
if config.Cmd == nil || len(config.Cmd) == 0 {
return nil, fmt.Errorf("No command specified")
}
// 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, config *Config) (*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, config)
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
}