package docker import ( "fmt" "github.com/dotcloud/docker/utils" "os" "path" "time" ) var defaultDns = []string{"8.8.8.8", "8.8.4.4"} 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 len(config.Entrypoint) != 0 && config.Cmd == nil { config.Cmd = []string{} } else 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] } var args []string var entrypoint string if len(config.Entrypoint) != 0 { entrypoint = config.Entrypoint[0] args = append(config.Entrypoint[1:], config.Cmd...) } else { entrypoint = config.Cmd[0] args = config.Cmd[1:] } container := &Container{ // FIXME: we should generate the ID here instead of receiving it as an argument ID: id, Created: time.Now(), Path: entrypoint, Args: args, //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 } resolvConf, err := utils.GetResolvConf() if err != nil { return nil, err } if len(config.Dns) == 0 && len(builder.runtime.Dns) == 0 && utils.CheckLocalDns(resolvConf) { //"WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns builder.runtime.Dns = defaultDns } // If custom dns exists, then create a resolv.conf for the container if len(config.Dns) > 0 || len(builder.runtime.Dns) > 0 { var dns []string if len(config.Dns) > 0 { dns = config.Dns } else { dns = builder.runtime.Dns } 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 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. if err := container.EnsureMounted(); err != nil { return nil, err } 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 }