V2 podman system service

* Added support for system service
* Enabled linting on the varlinkapi source, needed to support V2
  service command
* Added support for PODMAN_SOCKET

Skip linting deprecated code

Rather than introduce bugs by correcting deprecated code, linting the
code is being skipped. Code that is being ported into V2 is being
checked.

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

3 files changed, 184 insertions, 4 deletions

diff --git a/cmd/podmanV2/system/service.go b/cmd/podmanV2/system/service.go
new file mode 100644
index 000000000..5573f7039
--- /dev/null
+++ b/cmd/podmanV2/system/service.go
@@ -0,0 +1,124 @@
+package system
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/containers/libpod/cmd/podmanV2/registry"
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/containers/libpod/pkg/rootless"
+	"github.com/containers/libpod/pkg/systemd"
+	"github.com/containers/libpod/pkg/util"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+var (
+	srvDescription = `Run an API service
+
+Enable a listening service for API access to Podman commands.
+`
+
+	srvCmd = &cobra.Command{
+		Use:   "service [flags] [URI]",
+		Args:  cobra.MaximumNArgs(1),
+		Short: "Run API service",
+		Long:  srvDescription,
+		RunE:  service,
+		Example: `podman system service --time=0 unix:///tmp/podman.sock
+  podman system service --varlink --time=0 unix:///tmp/podman.sock`,
+	}
+
+	srvArgs = struct {
+		Timeout int64
+		Varlink bool
+	}{}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode},
+		Command: srvCmd,
+		Parent:  systemCmd,
+	})
+
+	flags := srvCmd.Flags()
+	flags.Int64VarP(&srvArgs.Timeout, "time", "t", 5, "Time until the service session expires in seconds.  Use 0 to disable the timeout")
+	flags.Int64Var(&srvArgs.Timeout, "timeout", 5, "Time until the service session expires in seconds.  Use 0 to disable the timeout")
+	flags.BoolVar(&srvArgs.Varlink, "varlink", false, "Use legacy varlink service instead of REST")
+
+	_ = flags.MarkDeprecated("varlink", "valink API is deprecated.")
+}
+
+func service(cmd *cobra.Command, args []string) error {
+	apiURI, err := resolveApiURI(args)
+	if err != nil {
+		return err
+	}
+	logrus.Infof("using API endpoint: \"%s\"", apiURI)
+
+	opts := entities.ServiceOptions{
+		URI:     apiURI,
+		Timeout: time.Duration(srvArgs.Timeout) * time.Second,
+		Command: cmd,
+	}
+
+	if srvArgs.Varlink {
+		return registry.ContainerEngine().VarlinkService(registry.GetContext(), opts)
+	}
+
+	logrus.Warn("This function is EXPERIMENTAL")
+	fmt.Fprintf(os.Stderr, "This function is EXPERIMENTAL.\n")
+	return registry.ContainerEngine().RestService(registry.GetContext(), opts)
+}
+
+func resolveApiURI(_url []string) (string, error) {
+
+	// When determining _*THE*_ listening endpoint --
+	// 1) User input wins always
+	// 2) systemd socket activation
+	// 3) rootless honors XDG_RUNTIME_DIR
+	// 4) if varlink -- adapter.DefaultVarlinkAddress
+	// 5) lastly adapter.DefaultAPIAddress
+
+	if _url == nil {
+		if v, found := os.LookupEnv("PODMAN_SOCKET"); found {
+			_url = []string{v}
+		}
+	}
+
+	switch {
+	case len(_url) > 0:
+		return _url[0], nil
+	case systemd.SocketActivated():
+		logrus.Info("using systemd socket activation to determine API endpoint")
+		return "", nil
+	case rootless.IsRootless():
+		xdg, err := util.GetRuntimeDir()
+		if err != nil {
+			return "", err
+		}
+
+		socketName := "podman.sock"
+		if srvArgs.Varlink {
+			socketName = "io.podman"
+		}
+		socketDir := filepath.Join(xdg, "podman", socketName)
+		if _, err := os.Stat(filepath.Dir(socketDir)); err != nil {
+			if os.IsNotExist(err) {
+				if err := os.Mkdir(filepath.Dir(socketDir), 0755); err != nil {
+					return "", err
+				}
+			} else {
+				return "", err
+			}
+		}
+		return "unix:" + socketDir, nil
+	case srvArgs.Varlink:
+		return registry.DefaultVarlinkAddress, nil
+	default:
+		return registry.DefaultAPIAddress, nil
+	}
+}
diff --git a/cmd/podmanV2/system/system.go b/cmd/podmanV2/system/system.go
index 4e805c7bd..b44632187 100644
--- a/cmd/podmanV2/system/system.go
+++ b/cmd/podmanV2/system/system.go
@@ -8,7 +8,7 @@ import (
 
 var (
 	// Command: podman _system_
-	cmd = &cobra.Command{
+	systemCmd = &cobra.Command{
 		Use:               "system",
 		Short:             "Manage podman",
 		Long:              "Manage podman",
@@ -21,10 +21,10 @@ var (
 func init() {
 	registry.Commands = append(registry.Commands, registry.CliCommand{
 		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
-		Command: cmd,
+		Command: systemCmd,
 	})
-	cmd.SetHelpTemplate(registry.HelpTemplate())
-	cmd.SetUsageTemplate(registry.UsageTemplate())
+	systemCmd.SetHelpTemplate(registry.HelpTemplate())
+	systemCmd.SetUsageTemplate(registry.UsageTemplate())
 }
 
 func preRunE(cmd *cobra.Command, args []string) error {
diff --git a/cmd/podmanV2/system/varlink.go b/cmd/podmanV2/system/varlink.go
new file mode 100644
index 000000000..da9af6fe4
--- /dev/null
+++ b/cmd/podmanV2/system/varlink.go
@@ -0,0 +1,56 @@
+package system
+
+import (
+	"time"
+
+	"github.com/containers/libpod/cmd/podmanV2/registry"
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/spf13/cobra"
+)
+
+var (
+	varlinkDescription = `Run varlink interface.  Podman varlink listens on the specified unix domain socket for incoming connects.
+
+  Tools speaking varlink protocol can remotely manage pods, containers and images.
+`
+	varlinkCmd = &cobra.Command{
+		Use:     "varlink [flags] [URI]",
+		Args:    cobra.MinimumNArgs(1),
+		Short:   "Run varlink interface",
+		Long:    varlinkDescription,
+		PreRunE: preRunE,
+		RunE:    varlinkE,
+		Example: `podman varlink unix:/run/podman/io.podman
+  podman varlink --timeout 5000 unix:/run/podman/io.podman`,
+	}
+	varlinkArgs = struct {
+		Timeout int64
+	}{}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
+		Command: varlinkCmd,
+	})
+	varlinkCmd.SetHelpTemplate(registry.HelpTemplate())
+	varlinkCmd.SetUsageTemplate(registry.UsageTemplate())
+
+	flags := varlinkCmd.Flags()
+	flags.Int64VarP(&varlinkArgs.Timeout, "time", "t", 1000, "Time until the varlink session expires in milliseconds.  Use 0 to disable the timeout")
+	flags.Int64Var(&varlinkArgs.Timeout, "timeout", 1000, "Time until the varlink session expires in milliseconds.  Use 0 to disable the timeout")
+
+}
+
+func varlinkE(cmd *cobra.Command, args []string) error {
+	uri := registry.DefaultVarlinkAddress
+	if len(args) > 0 {
+		uri = args[0]
+	}
+	opts := entities.ServiceOptions{
+		URI:     uri,
+		Timeout: time.Duration(varlinkArgs.Timeout) * time.Second,
+		Command: cmd,
+	}
+	return registry.ContainerEngine().VarlinkService(registry.GetContext(), opts)
+}