package container import ( "context" "fmt" "io" "os" "regexp" "github.com/docker/cli/cli" "github.com/docker/cli/cli/command" "github.com/docker/cli/cli/command/image" "github.com/docker/distribution/reference" "github.com/docker/docker/api/types" "github.com/docker/docker/api/types/container" apiclient "github.com/docker/docker/client" "github.com/docker/docker/pkg/jsonmessage" "github.com/docker/docker/registry" "github.com/pkg/errors" "github.com/spf13/cobra" "github.com/spf13/pflag" ) type createOptions struct { name string platform string untrusted bool } // NewCreateCommand creates a new cobra.Command for `docker create` func NewCreateCommand(dockerCli command.Cli) *cobra.Command { var opts createOptions var copts *containerOptions cmd := &cobra.Command{ Use: "create [OPTIONS] IMAGE [COMMAND] [ARG...]", Short: "Create a new container", Args: cli.RequiresMinArgs(1), RunE: func(cmd *cobra.Command, args []string) error { copts.Image = args[0] if len(args) > 1 { copts.Args = args[1:] } return runCreate(dockerCli, cmd.Flags(), &opts, copts) }, } flags := cmd.Flags() flags.SetInterspersed(false) flags.StringVar(&opts.name, "name", "", "Assign a name to the container") // Add an explicit help that doesn't have a `-h` to prevent the conflict // with hostname flags.Bool("help", false, "Print usage") command.AddPlatformFlag(flags, &opts.platform) command.AddTrustVerificationFlags(flags, &opts.untrusted, dockerCli.ContentTrustEnabled()) copts = addFlags(flags) return cmd } func runCreate(dockerCli command.Cli, flags *pflag.FlagSet, opts *createOptions, copts *containerOptions) error { containerConfig, err := parse(flags, copts) if err != nil { reportError(dockerCli.Err(), "create", err.Error(), true) return cli.StatusError{StatusCode: 125} } if err = validateAPIVersion(containerConfig, dockerCli.Client().ClientVersion()); err != nil { reportError(dockerCli.Err(), "create", err.Error(), true) return cli.StatusError{StatusCode: 125} } response, err := createContainer(context.Background(), dockerCli, containerConfig, opts) if err != nil { return err } fmt.Fprintln(dockerCli.Out(), response.ID) return nil } func pullImage(ctx context.Context, dockerCli command.Cli, image string, platform string, out io.Writer) error { ref, err := reference.ParseNormalizedNamed(image) if err != nil { return err } // Resolve the Repository name from fqn to RepositoryInfo repoInfo, err := registry.ParseRepositoryInfo(ref) if err != nil { return err } authConfig := command.ResolveAuthConfig(ctx, dockerCli, repoInfo.Index) encodedAuth, err := command.EncodeAuthToBase64(authConfig) if err != nil { return err } options := types.ImageCreateOptions{ RegistryAuth: encodedAuth, Platform: platform, } responseBody, err := dockerCli.Client().ImageCreate(ctx, image, options) if err != nil { return err } defer responseBody.Close() return jsonmessage.DisplayJSONMessagesStream( responseBody, out, dockerCli.Out().FD(), dockerCli.Out().IsTerminal(), nil) } type cidFile struct { path string file *os.File written bool } func (cid *cidFile) Close() error { if cid.file == nil { return nil } cid.file.Close() if cid.written { return nil } if err := os.Remove(cid.path); err != nil { return errors.Errorf("failed to remove the CID file '%s': %s \n", cid.path, err) } return nil } func (cid *cidFile) Write(id string) error { if cid.file == nil { return nil } if _, err := cid.file.Write([]byte(id)); err != nil { return errors.Errorf("Failed to write the container ID to the file: %s", err) } cid.written = true return nil } func newCIDFile(path string) (*cidFile, error) { if path == "" { return &cidFile{}, nil } if _, err := os.Stat(path); err == nil { return nil, errors.Errorf("Container ID file found, make sure the other container isn't running or delete %s", path) } f, err := os.Create(path) if err != nil { return nil, errors.Errorf("Failed to create the container ID file: %s", err) } return &cidFile{path: path, file: f}, nil } func createContainer(ctx context.Context, dockerCli command.Cli, containerConfig *containerConfig, opts *createOptions) (*container.ContainerCreateCreatedBody, error) { config := containerConfig.Config hostConfig := containerConfig.HostConfig networkingConfig := containerConfig.NetworkingConfig stderr := dockerCli.Err() warnOnOomKillDisable(*hostConfig, stderr) warnOnLocalhostDNS(*hostConfig, stderr) var ( trustedRef reference.Canonical namedRef reference.Named ) containerIDFile, err := newCIDFile(hostConfig.ContainerIDFile) if err != nil { return nil, err } defer containerIDFile.Close() ref, err := reference.ParseAnyReference(config.Image) if err != nil { return nil, err } if named, ok := ref.(reference.Named); ok { namedRef = reference.TagNameOnly(named) if taggedRef, ok := namedRef.(reference.NamedTagged); ok && !opts.untrusted { var err error trustedRef, err = image.TrustedReference(ctx, dockerCli, taggedRef, nil) if err != nil { return nil, err } config.Image = reference.FamiliarString(trustedRef) } } //create the container response, err := dockerCli.Client().ContainerCreate(ctx, config, hostConfig, networkingConfig, opts.name) //if image not found try to pull it if err != nil { if apiclient.IsErrNotFound(err) && namedRef != nil { fmt.Fprintf(stderr, "Unable to find image '%s' locally\n", reference.FamiliarString(namedRef)) // we don't want to write to stdout anything apart from container.ID if err := pullImage(ctx, dockerCli, config.Image, opts.platform, stderr); err != nil { return nil, err } if taggedRef, ok := namedRef.(reference.NamedTagged); ok && trustedRef != nil { if err := image.TagTrusted(ctx, dockerCli, trustedRef, taggedRef); err != nil { return nil, err } } // Retry var retryErr error response, retryErr = dockerCli.Client().ContainerCreate(ctx, config, hostConfig, networkingConfig, opts.name) if retryErr != nil { return nil, retryErr } } else { return nil, err } } for _, warning := range response.Warnings { fmt.Fprintf(stderr, "WARNING: %s\n", warning) } err = containerIDFile.Write(response.ID) return &response, err } func warnOnOomKillDisable(hostConfig container.HostConfig, stderr io.Writer) { if hostConfig.OomKillDisable != nil && *hostConfig.OomKillDisable && hostConfig.Memory == 0 { fmt.Fprintln(stderr, "WARNING: Disabling the OOM killer on containers without setting a '-m/--memory' limit may be dangerous.") } } // check the DNS settings passed via --dns against localhost regexp to warn if // they are trying to set a DNS to a localhost address func warnOnLocalhostDNS(hostConfig container.HostConfig, stderr io.Writer) { for _, dnsIP := range hostConfig.DNS { if isLocalhost(dnsIP) { fmt.Fprintf(stderr, "WARNING: Localhost DNS setting (--dns=%s) may fail in containers.\n", dnsIP) return } } } // IPLocalhost is a regex pattern for IPv4 or IPv6 loopback range. const ipLocalhost = `((127\.([0-9]{1,3}\.){2}[0-9]{1,3})|(::1)$)` var localhostIPRegexp = regexp.MustCompile(ipLocalhost) // IsLocalhost returns true if ip matches the localhost IP regular expression. // Used for determining if nameserver settings are being passed which are // localhost addresses func isLocalhost(ip string) bool { return localhostIPRegexp.MatchString(ip) }