Add --format flag for docker plugin ls

This fix tries to address the enhancement discussed in 28735 to add
`--format` for the output of `docker plugin ls`.

This fix
1. Add `--format` and `--quiet` flags to `docker plugin ls`
2. Convert the current implementation to use `formatter`, consistent with
   other docker list commands.
3. Add `pluginsFormat` for config.json.

Related docs has been updated.

Several unit tests have been added to cover the changes.

This fix is related to 28708 and 28735.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Upstream-commit: 1c0d37fa7f04ade13e65aff74ea0495bb846d782
Component: engine

components/engine/integration-cli/docker_cli_plugins_test.go

@@ -401,3 +401,29 @@ func (s *DockerSuite) TestPluginIDPrefix(c *check.C) {
 	c.Assert(out, checker.Not(checker.Contains), pName)
 	c.Assert(out, checker.Not(checker.Contains), pTag)
 }
+
+func (s *DockerSuite) TestPluginListDefaultFormat(c *check.C) {
+	testRequires(c, DaemonIsLinux, Network, IsAmd64)
+
+	config, err := ioutil.TempDir("", "config-file-")
+	c.Assert(err, check.IsNil)
+	defer os.RemoveAll(config)
+
+	err = ioutil.WriteFile(filepath.Join(config, "config.json"), []byte(`{"pluginsFormat": "raw"}`), 0644)
+	c.Assert(err, check.IsNil)
+
+	out, _ := dockerCmd(c, "plugin", "install", "--grant-all-permissions", pName)
+	c.Assert(strings.TrimSpace(out), checker.Contains, pName)
+
+	out, _ = dockerCmd(c, "plugin", "inspect", "--format", "{{.ID}}", pNameWithTag)
+	id := strings.TrimSpace(out)
+
+	// We expect the format to be in `raw + --no-trunc`
+	expectedOutput := fmt.Sprintf(`plugin_id: %s
+name: %s
+description: A sample volume plugin for Docker
+enabled: true`, id, pNameWithTag)
+
+	out, _ = dockerCmd(c, "--config", config, "plugin", "ls", "--no-trunc")
+	c.Assert(strings.TrimSpace(out), checker.Contains, expectedOutput)
+}