Add --format to connection list

Add support for the --format option to podman system connection list.

Signed-off-by: Jhon Honce <jhonce@redhat.com>

3 files changed, 52 insertions, 8 deletions

diff --git a/cmd/podman/system/connection/list.go b/cmd/podman/system/connection/list.go
index b0b15b57d..2f74215c1 100644
--- a/cmd/podman/system/connection/list.go
+++ b/cmd/podman/system/connection/list.go
@@ -1,11 +1,13 @@
 package connection
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/containers/common/pkg/completion"
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v3/cmd/podman/common"
 	"github.com/containers/podman/v3/cmd/podman/registry"
 	"github.com/containers/podman/v3/cmd/podman/system"
 	"github.com/containers/podman/v3/cmd/podman/validate"
@@ -14,13 +16,14 @@ import (
 
 var (
 	listCmd = &cobra.Command{
-		Use:     "list",
+		Use:     "list [options]",
 		Aliases: []string{"ls"},
 		Args:    validate.NoArgs,
 		Short:   "List destination for the Podman service(s)",
 		Long:    `List destination information for the Podman service(s) in podman configuration`,
 		Example: `podman system connection list
-  podman system connection ls`,
+  podman system connection ls
+  podman system connection ls --format=json`,
 		ValidArgsFunction: completion.AutocompleteNone,
 		RunE:              list,
 		TraverseChildren:  false,
@@ -32,6 +35,9 @@ func init() {
 		Command: listCmd,
 		Parent:  system.ConnectionCmd,
 	})
+
+	listCmd.Flags().String("format", "", "Custom Go template for printing connections")
+	_ = listCmd.RegisterFlagCompletionFunc("format", common.AutocompleteFormat(namedDestination{}))
 }
 
 type namedDestination struct {
@@ -39,7 +45,7 @@ type namedDestination struct {
 	config.Destination
 }
 
-func list(_ *cobra.Command, _ []string) error {
+func list(cmd *cobra.Command, _ []string) error {
 	cfg, err := config.ReadCustomConfig()
 	if err != nil {
 		return err
@@ -71,8 +77,22 @@ func list(_ *cobra.Command, _ []string) error {
 		rows = append(rows, r)
 	}
 
-	// TODO: Allow user to override format
-	format := "{{range . }}{{.Name}}\t{{.Identity}}\t{{.URI}}\n{{end -}}"
+	format := "{{.Name}}\t{{.Identity}}\t{{.URI}}\n"
+	switch {
+	case report.IsJSON(cmd.Flag("format").Value.String()):
+		buf, err := registry.JSONLibrary().MarshalIndent(rows, "", "    ")
+		if err == nil {
+			fmt.Println(string(buf))
+		}
+		return err
+	default:
+		if cmd.Flag("format").Changed {
+			format = cmd.Flag("format").Value.String()
+			format = report.NormalizeFormat(format)
+		}
+	}
+	format = report.EnforceRange(format)
+
 	tmpl, err := report.NewTemplate("list").Parse(format)
 	if err != nil {
 		return err
@@ -84,6 +104,9 @@ func list(_ *cobra.Command, _ []string) error {
 	}
 	defer w.Flush()
 
-	_ = tmpl.Execute(w, hdrs)
+	isTable := report.HasTable(cmd.Flag("format").Value.String())
+	if !cmd.Flag("format").Changed || isTable {
+		_ = tmpl.Execute(w, hdrs)
+	}
 	return tmpl.Execute(w, rows)
 }
diff --git a/docs/source/markdown/podman-system-connection-list.1.md b/docs/source/markdown/podman-system-connection-list.1.md
index f5fb5c8e3..6b25a045d 100644
--- a/docs/source/markdown/podman-system-connection-list.1.md
+++ b/docs/source/markdown/podman-system-connection-list.1.md
@@ -4,13 +4,28 @@
 podman\-system\-connection\-list - List the destination for the Podman service(s)
 
 ## SYNOPSIS
-**podman system connection list**
+**podman system connection list** [*options*]
 
-**podman system connection ls**
+**podman system connection ls** [*options*]
 
 ## DESCRIPTION
 List ssh destination(s) for podman service(s).
 
+## OPTIONS
+
+#### **--format**=*format*
+
+Change the default output format.  This can be of a supported type like 'json' or a Go template.
+Valid placeholders for the Go template listed below:
+
+| **Placeholder** | **Description**                                                               |
+| --------------- | ----------------------------------------------------------------------------- |
+| *.Name*         | Connection Name/Identifier |
+| *.Identity*     | Path to file containing SSH identity |
+| *.URI*          | URI to podman service. Valid schemes are ssh://[user@]*host*[:port]*Unix domain socket*[?secure=True], unix://*Unix domain socket*, and tcp://localhost[:*port*] |
+
+An asterisk is appended to the default connection.
+
 ## EXAMPLE
 ```
 $ podman system connection list
diff --git a/test/e2e/system_connection_test.go b/test/e2e/system_connection_test.go
index 4697cf860..7c922a648 100644
--- a/test/e2e/system_connection_test.go
+++ b/test/e2e/system_connection_test.go
@@ -147,6 +147,12 @@ var _ = Describe("podman system connection", func() {
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(Exit(0))
 		Expect(session.Out).Should(Say("Name *Identity *URI"))
+
+		cmd = []string{"system", "connection", "list", "--format", "{{.Name}}"}
+		session = podmanTest.Podman(cmd)
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).Should(Equal("devl* qe"))
 	})
 
 	It("failed default", func() {