Add podman machine list

podman machine list lists all virtual machines & indicates the default VM
connection, if it exists. it also can take a --format flag arg as a go
template.

[NO TESTS NEEDED]

Signed-off-by: Ashley Cui <acui@redhat.com>

7 files changed, 262 insertions, 5 deletions

diff --git a/cmd/podman/machine/list.go b/cmd/podman/machine/list.go
new file mode 100644
index 000000000..3c8368c6b
--- /dev/null
+++ b/cmd/podman/machine/list.go
@@ -0,0 +1,143 @@
+// +build amd64,linux arm64,linux amd64,darwin arm64,darwin
+
+package machine
+
+import (
+	"os"
+	"sort"
+	"text/tabwriter"
+	"text/template"
+	"time"
+
+	"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/parse"
+	"github.com/containers/podman/v3/cmd/podman/registry"
+	"github.com/containers/podman/v3/cmd/podman/validate"
+	"github.com/containers/podman/v3/pkg/domain/entities"
+	"github.com/containers/podman/v3/pkg/machine"
+	"github.com/containers/podman/v3/pkg/machine/qemu"
+	"github.com/docker/go-units"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+)
+
+var (
+	lsCmd = &cobra.Command{
+		Use:     "list [options]",
+		Aliases: []string{"ls"},
+		Short:   "List machines",
+		Long:    "List Podman managed virtual machines.",
+		RunE:    list,
+		Args:    validate.NoArgs,
+		Example: `podman machine list,
+  podman machine ls`,
+		ValidArgsFunction: completion.AutocompleteNone,
+	}
+	listFlag = listFlagType{}
+)
+
+type listFlagType struct {
+	format    string
+	noHeading bool
+}
+
+type machineReporter struct {
+	Name    string
+	Created string
+	LastUp  string
+	VMType  string
+}
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
+		Command: lsCmd,
+		Parent:  machineCmd,
+	})
+
+	flags := lsCmd.Flags()
+	formatFlagName := "format"
+	flags.StringVar(&listFlag.format, formatFlagName, "{{.Name}}\t{{.VMType}}\t{{.Created}}\t{{.LastUp}}\n", "Format volume output using Go template")
+	_ = lsCmd.RegisterFlagCompletionFunc(formatFlagName, completion.AutocompleteNone)
+}
+
+func list(cmd *cobra.Command, args []string) error {
+	var opts machine.ListOptions
+	// We only have qemu VM's for now
+	listResponse, err := qemu.List(opts)
+	if err != nil {
+		return errors.Wrap(err, "error listing vms")
+	}
+
+	// Sort by last run
+	sort.Slice(listResponse, func(i, j int) bool {
+		return listResponse[i].LastUp.After(listResponse[j].LastUp)
+	})
+	// Bring currently running machines to top
+	sort.Slice(listResponse, func(i, j int) bool {
+		return listResponse[i].Running
+	})
+	machineReporter, err := toHumanFormat(listResponse)
+	if err != nil {
+		return err
+	}
+
+	return outputTemplate(cmd, machineReporter)
+}
+
+func outputTemplate(cmd *cobra.Command, responses []*machineReporter) error {
+	headers := report.Headers(machineReporter{}, map[string]string{
+		"LastUp": "LAST UP",
+		"VmType": "VM TYPE",
+	})
+
+	row := report.NormalizeFormat(listFlag.format)
+	format := parse.EnforceRange(row)
+
+	tmpl, err := template.New("list machines").Parse(format)
+	if err != nil {
+		return err
+	}
+	w := tabwriter.NewWriter(os.Stdout, 12, 2, 2, ' ', 0)
+	defer w.Flush()
+
+	if cmd.Flags().Changed("format") && !parse.HasTable(listFlag.format) {
+		listFlag.noHeading = true
+	}
+
+	if !listFlag.noHeading {
+		if err := tmpl.Execute(w, headers); err != nil {
+			return errors.Wrapf(err, "failed to write report column headers")
+		}
+	}
+	return tmpl.Execute(w, responses)
+}
+
+func toHumanFormat(vms []*machine.ListResponse) ([]*machineReporter, error) {
+	cfg, err := config.ReadCustomConfig()
+	if err != nil {
+		return nil, err
+	}
+
+	humanResponses := make([]*machineReporter, 0, len(vms))
+	for _, vm := range vms {
+		response := new(machineReporter)
+		if vm.Name == cfg.Engine.ActiveService {
+			response.Name = vm.Name + "*"
+		} else {
+			response.Name = vm.Name
+		}
+		if vm.Running {
+			response.LastUp = "Currently running"
+		} else {
+			response.LastUp = units.HumanDuration(time.Since(vm.LastUp)) + " ago"
+		}
+		response.Created = units.HumanDuration(time.Since(vm.CreatedAt)) + " ago"
+		response.VMType = vm.VMType
+
+		humanResponses = append(humanResponses, response)
+	}
+	return humanResponses, nil
+}
diff --git a/docs/source/machine.rst b/docs/source/machine.rst
index be9ef1e95..16c042173 100644
--- a/docs/source/machine.rst
+++ b/docs/source/machine.rst
@@ -3,6 +3,7 @@ Machine
 
 
 :doc:`init <markdown/podman-machine-init.1>` Initialize a new virtual machine
+:doc:`list <markdown/podman-machine-list.1>` List virtual machines
 :doc:`rm <markdown/podman-machine-rm.1>` Remove a virtual machine
 :doc:`ssh <markdown/podman-machine-ssh.1>` SSH into a virtual machine
 :doc:`start <markdown/podman-machine-start.1>` Start a virtual machine
diff --git a/docs/source/markdown/links/podman-machine-ls.1 b/docs/source/markdown/links/podman-machine-ls.1
new file mode 100644
index 000000000..f6acb7f74
--- /dev/null
+++ b/docs/source/markdown/links/podman-machine-ls.1
@@ -0,0 +1 @@
+.so man1/podman-machine-list.1
diff --git a/docs/source/markdown/podman-machine-list.1.md b/docs/source/markdown/podman-machine-list.1.md
new file mode 100644
index 000000000..bd5608258
--- /dev/null
+++ b/docs/source/markdown/podman-machine-list.1.md
@@ -0,0 +1,50 @@
+% podman-machine-ls(1)
+
+## NAME
+podman\-machine\-list - List virtual machines
+
+## SYNOPSIS
+**podman machine list** [*options*]
+
+**podman machine ls** [*options*]
+
+## DESCRIPTION
+
+List Podman managed virtual machines.
+
+Podman on macOS requires a virtual machine. This is because containers are Linux -
+containers do not run on any other OS because containers' core functionality is
+tied to the Linux kernel.
+
+## OPTIONS
+
+#### **\-\-format**=*format*
+
+Format list output using a Go template.
+
+Valid placeholders for the Go template are listed below:
+
+| **Placeholder** | **Description**                 |
+| --------------- | ------------------------------- |
+| .Name           | VM name                         |
+| .Created        | Time since VM creation          |
+| .LastUp         | Time since the VM was last run  |
+| .VMType         | VM type                      	|
+
+#### **\-\-help**
+
+Print usage statement.
+
+## EXAMPLES
+
+```
+$ podman machine list
+
+$ podman machine ls --format {{.Name}}\t{{.VMType}}\t{{.Created}}\t{{.LastUp}}\n
+```
+
+## SEE ALSO
+podman-machine(1)
+
+## HISTORY
+March 2021, Originally compiled by Ashley Cui <acui@redhat.com>
diff --git a/docs/source/markdown/podman-machine.1.md b/docs/source/markdown/podman-machine.1.md
index a5d3b78df..693f42fe3 100644
--- a/docs/source/markdown/podman-machine.1.md
+++ b/docs/source/markdown/podman-machine.1.md
@@ -14,13 +14,14 @@ podman\-machine - Manage Podman's virtual machine
 | Command | Man Page                                                | Description                       |
 | ------- | ------------------------------------------------------- | --------------------------------- |
 | init    | [podman-machine-init(1)](podman-machine-init.1.md)      | Initialize a new virtual machine  |
-| rm | [podman-machine-rm(1)](podman-machine-rm.1.md)| Remove a virtual machine     |
-| ssh     | [podman-machine-ssh(1)](podman-machine-ssh.1.md)   | SSH into a virtual machine    |
-| start   | [podman-machine-start(1)](podman-machine-start.1.md)    | Start a virtual machine       |
-| stop    | [podman-machine-stop(1)](podman-machine-stop.1.md)      | Stop a virtual machine        |
+| list    | [podman-machine-list(1)](podman-machine-list.1.md)      | List virtual machines             |
+| rm      | [podman-machine-rm(1)](podman-machine-rm.1.md)          | Remove a virtual machine          |
+| ssh     | [podman-machine-ssh(1)](podman-machine-ssh.1.md)        | SSH into a virtual machine        |
+| start   | [podman-machine-start(1)](podman-machine-start.1.md)    | Start a virtual machine           |
+| stop    | [podman-machine-stop(1)](podman-machine-stop.1.md)      | Stop a virtual machine            |
 
 ## SEE ALSO
-podman(1)
+podman(1), podman-machine-init(1), podman-machine-list(1), podman-machine-rm(1), podman-machine-ssh(1), podman-machine-start(1), podman-machine-stop(1)
 
 ## HISTORY
 March 2021, Originally compiled by Ashley Cui <acui@redhat.com>
diff --git a/pkg/machine/config.go b/pkg/machine/config.go
index 273deca00..554ea7c97 100644
--- a/pkg/machine/config.go
+++ b/pkg/machine/config.go
@@ -5,6 +5,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"time"
 
 	"github.com/containers/storage/pkg/homedir"
 	"github.com/pkg/errors"
@@ -44,6 +45,16 @@ type Download struct {
 	VMName                string
 }
 
+type ListOptions struct{}
+
+type ListResponse struct {
+	Name      string
+	CreatedAt time.Time
+	LastUp    time.Time
+	Running   bool
+	VMType    string
+}
+
 type SSHOptions struct {
 	Execute bool
 	Args    []string
diff --git a/pkg/machine/qemu/machine.go b/pkg/machine/qemu/machine.go
index 652a077cc..58486fc73 100644
--- a/pkg/machine/qemu/machine.go
+++ b/pkg/machine/qemu/machine.go
@@ -10,6 +10,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/containers/podman/v3/pkg/machine"
@@ -426,3 +427,52 @@ func getDiskSize(path string) (uint64, error) {
 	}
 	return tmpInfo.VirtualSize, nil
 }
+
+// List lists all vm's that use qemu virtualization
+func List(opts machine.ListOptions) ([]*machine.ListResponse, error) {
+	vmConfigDir, err := machine.GetConfDir(vmtype)
+	if err != nil {
+		return nil, err
+	}
+
+	var listed []*machine.ListResponse
+
+	if err = filepath.Walk(vmConfigDir, func(path string, info os.FileInfo, err error) error {
+		vm := new(MachineVM)
+		if strings.HasSuffix(info.Name(), ".json") {
+			fullPath := filepath.Join(vmConfigDir, info.Name())
+			b, err := ioutil.ReadFile(fullPath)
+			if err != nil {
+				return err
+			}
+			err = json.Unmarshal(b, vm)
+			if err != nil {
+				return err
+			}
+			listEntry := new(machine.ListResponse)
+
+			listEntry.Name = vm.Name
+			listEntry.VMType = "qemu"
+			fi, err := os.Stat(fullPath)
+			if err != nil {
+				return err
+			}
+			listEntry.CreatedAt = fi.ModTime()
+
+			fi, err = os.Stat(vm.ImagePath)
+			if err != nil {
+				return err
+			}
+			listEntry.LastUp = fi.ModTime()
+			if vm.isRunning() {
+				listEntry.Running = true
+			}
+
+			listed = append(listed, listEntry)
+		}
+		return nil
+	}); err != nil {
+		return nil, err
+	}
+	return listed, err
+}