Merge pull request #4385 from khia/json_format

Support json output in --format flag of docker inspect

api/client.go

@@ -37,6 +37,13 @@ import (
 	"time"
 )
 
+var funcMap = template.FuncMap{
+	"json": func(v interface{}) string {
+		a, _ := json.Marshal(v)
+		return string(a)
+	},
+}
+
 var (
 	ErrConnectionRefused = errors.New("Can't connect to docker daemon. Is 'docker -d' running on this host?")
 )
@@ -640,7 +647,7 @@ func (cli *DockerCli) CmdInspect(args ...string) error {
 	var tmpl *template.Template
 	if *tmplStr != "" {
 		var err error
-		if tmpl, err = template.New("").Parse(*tmplStr); err != nil {
+		if tmpl, err = template.New("").Funcs(funcMap).Parse(*tmplStr); err != nil {
 			fmt.Fprintf(cli.err, "Template parsing error: %v\n", err)
 			return &utils.StatusError{StatusCode: 64,
 				Status: "Template parsing error: " + err.Error()}

docs/sources/reference/commandline/cli.rst

@@ -809,6 +809,19 @@ we ask for the ``HostPort`` field to get the public address.
 
     $ sudo docker inspect -format='{{(index (index .NetworkSettings.Ports "8787/tcp") 0).HostPort}}' $INSTANCE_ID
 
+Get config
+..........
+
+The ``.Field`` syntax doesn't work when the field contains JSON data,
+but the template language's custom ``json`` function does. The ``.config``
+section contains complex json object, so to grab it as JSON, you use ``json``
+to convert config object into JSON
+
+.. code-block:: bash
+
+    $ sudo docker inspect -format='{{json .config}}' $INSTANCE_ID
+
+
 .. _cli_kill:
 
 ``kill``