moby/api/client/inspect.go

package client

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"strings"
	"text/template"

	flag "github.com/docker/docker/pkg/mflag"
)

// CmdInspect displays low-level information on one or more containers or images.
//
// Usage: docker inspect [OPTIONS] CONTAINER|IMAGE [CONTAINER|IMAGE...]
func (cli *DockerCli) CmdInspect(args ...string) error {
	cmd := cli.Subcmd("inspect", "CONTAINER|IMAGE [CONTAINER|IMAGE...]", "Return low-level information on a container or image", true)
	tmplStr := cmd.String([]string{"f", "#format", "-format"}, "", "Format the output using the given go template")
	cmd.Require(flag.Min, 1)

	cmd.ParseFlags(args, true)

	var tmpl *template.Template
	if *tmplStr != "" {
		var err error
		if tmpl, err = template.New("").Funcs(funcMap).Parse(*tmplStr); err != nil {
			fmt.Fprintf(cli.err, "Template parsing error: %v\n", err)
			return StatusError{StatusCode: 64,
				Status: "Template parsing error: " + err.Error()}
		}
	}

	indented := new(bytes.Buffer)
	indented.WriteByte('[')
	status := 0

	for _, name := range cmd.Args() {
		obj, _, err := readBody(cli.call("GET", "/containers/"+name+"/json", nil, nil))
		if err != nil {
			obj, _, err = readBody(cli.call("GET", "/images/"+name+"/json", nil, nil))
			if err != nil {
				if strings.Contains(err.Error(), "No such") {
					fmt.Fprintf(cli.err, "Error: No such image or container: %s\n", name)
				} else {
					fmt.Fprintf(cli.err, "%s", err)
				}
				status = 1
				continue
			}
		}

		if tmpl == nil {
			if err = json.Indent(indented, obj, "", "    "); err != nil {
				fmt.Fprintf(cli.err, "%s\n", err)
				status = 1
				continue
			}
		} else {
			var value interface{}

			// Do not use `json.Unmarshal()` because unmarshal JSON into
			// an interface value, Unmarshal stores JSON numbers in
			// float64, which is different from `json.Indent()` does.
			dec := json.NewDecoder(bytes.NewReader(obj))
			dec.UseNumber()
			if err := dec.Decode(&value); err != nil {
				fmt.Fprintf(cli.err, "%s\n", err)
				status = 1
				continue
			}
			if err := tmpl.Execute(cli.out, value); err != nil {
				return err
			}
			cli.out.Write([]byte{'\n'})
		}
		indented.WriteString(",")
	}

	if indented.Len() > 1 {
		// Remove trailing ','
		indented.Truncate(indented.Len() - 1)
	}
	indented.WriteString("]\n")

	if tmpl == nil {
		if _, err := io.Copy(cli.out, indented); err != nil {
			return err
		}
	}

	if status != 0 {
		return StatusError{StatusCode: status}
	}
	return nil
}