Implement Podman Container Clone

podman container clone takes the id of an existing continer and creates a specgen from the given container's config
recreating all proper namespaces and overriding spec options like resource limits and the container name if given in the cli options

this command utilizes the common function DefineCreateFlags meaning that we can funnel as many create options as we want
into clone over time allowing the user to clone with as much or as little of the original config as they want.

container clone takes a second argument which is a new name and a third argument which is an image name to use instead of the original container's

the current supported flags are:

--destroy (remove the original container)
--name (new ctr name)
--cpus (sets cpu period and quota)
--cpuset-cpus
--cpu-period
--cpu-rt-period
--cpu-rt-runtime
--cpu-shares
--cpuset-mems
--memory
--run

resolves #10875

Signed-off-by: cdoern <cdoern@redhat.com>
Signed-off-by: cdoern <cbdoer23@g.holycross.edu>
Signed-off-by: cdoern <cdoern@redhat.com>

1 files changed, 150 insertions, 0 deletions

diff --git a/pkg/specgen/generate/container.go b/pkg/specgen/generate/container.go
index a4d862a60..64669f34d 100644
--- a/pkg/specgen/generate/container.go
+++ b/pkg/specgen/generate/container.go
@@ -2,6 +2,7 @@ package generate
 
 import (
 	"context"
+	"encoding/json"
 	"os"
 	"strings"
 	"time"
@@ -335,3 +336,152 @@ func FinishThrottleDevices(s *specgen.SpecGenerator) error {
 	}
 	return nil
 }
+
+// ConfigToSpec takes a completed container config and converts it back into a specgenerator for purposes of cloning an exisiting container
+func ConfigToSpec(rt *libpod.Runtime, specg *specgen.SpecGenerator, contaierID string) (*libpod.Container, error) {
+	c, err := rt.LookupContainer(contaierID)
+	if err != nil {
+		return nil, err
+	}
+	conf := c.Config()
+
+	tmpSystemd := conf.Systemd
+	tmpMounts := conf.Mounts
+
+	conf.Systemd = nil
+	conf.Mounts = []string{}
+
+	specg.Pod = conf.Pod
+
+	matching, err := json.Marshal(conf)
+	if err != nil {
+		return nil, err
+	}
+
+	err = json.Unmarshal(matching, specg)
+	if err != nil {
+		return nil, err
+	}
+	conf.Systemd = tmpSystemd
+	conf.Mounts = tmpMounts
+
+	if conf.Spec != nil && conf.Spec.Linux != nil && conf.Spec.Linux.Resources != nil {
+		if specg.ResourceLimits == nil {
+			specg.ResourceLimits = conf.Spec.Linux.Resources
+		}
+	}
+
+	nameSpaces := []string{"pid", "net", "cgroup", "ipc", "uts", "user"}
+	containers := []string{conf.PIDNsCtr, conf.NetNsCtr, conf.CgroupNsCtr, conf.IPCNsCtr, conf.UTSNsCtr, conf.UserNsCtr}
+	place := []*specgen.Namespace{&specg.PidNS, &specg.NetNS, &specg.CgroupNS, &specg.IpcNS, &specg.UtsNS, &specg.UserNS}
+	for i, ns := range containers {
+		if len(ns) > 0 {
+			ns := specgen.Namespace{NSMode: specgen.FromContainer, Value: ns}
+			place[i] = &ns
+		} else {
+			switch nameSpaces[i] {
+			case "pid":
+				specg.PidNS = specgen.Namespace{NSMode: specgen.Default} //default
+			case "net":
+				switch {
+				case conf.NetMode.IsBridge():
+					toExpose := make(map[uint16]string, len(conf.ExposedPorts))
+					for _, expose := range []map[uint16][]string{conf.ExposedPorts} {
+						for port, proto := range expose {
+							toExpose[port] = strings.Join(proto, ",")
+						}
+					}
+					specg.Expose = toExpose
+					specg.PortMappings = conf.PortMappings
+					specg.NetNS = specgen.Namespace{NSMode: specgen.Bridge}
+				case conf.NetMode.IsSlirp4netns():
+					toExpose := make(map[uint16]string, len(conf.ExposedPorts))
+					for _, expose := range []map[uint16][]string{conf.ExposedPorts} {
+						for port, proto := range expose {
+							toExpose[port] = strings.Join(proto, ",")
+						}
+					}
+					specg.Expose = toExpose
+					specg.PortMappings = conf.PortMappings
+					netMode := strings.Split(string(conf.NetMode), ":")
+					var val string
+					if len(netMode) > 1 {
+						val = netMode[1]
+					}
+					specg.NetNS = specgen.Namespace{NSMode: specgen.Slirp, Value: val}
+				case conf.NetMode.IsPrivate():
+					specg.NetNS = specgen.Namespace{NSMode: specgen.Private}
+				case conf.NetMode.IsDefault():
+					specg.NetNS = specgen.Namespace{NSMode: specgen.Default}
+				case conf.NetMode.IsUserDefined():
+					specg.NetNS = specgen.Namespace{NSMode: specgen.Path, Value: strings.Split(string(conf.NetMode), ":")[1]}
+				case conf.NetMode.IsContainer():
+					specg.NetNS = specgen.Namespace{NSMode: specgen.FromContainer, Value: strings.Split(string(conf.NetMode), ":")[1]}
+				case conf.NetMode.IsPod():
+					specg.NetNS = specgen.Namespace{NSMode: specgen.FromPod, Value: strings.Split(string(conf.NetMode), ":")[1]}
+				}
+			case "cgroup":
+				specg.CgroupNS = specgen.Namespace{NSMode: specgen.Default} //default
+			case "ipc":
+				if conf.ShmDir == "/dev/shm" {
+					specg.IpcNS = specgen.Namespace{NSMode: specgen.Host}
+				} else {
+					specg.IpcNS = specgen.Namespace{NSMode: specgen.Default} //default
+				}
+			case "uts":
+				specg.UtsNS = specgen.Namespace{NSMode: specgen.Default} //default
+			case "user":
+				if conf.AddCurrentUserPasswdEntry {
+					specg.UserNS = specgen.Namespace{NSMode: specgen.KeepID}
+				} else {
+					specg.UserNS = specgen.Namespace{NSMode: specgen.Default} //default
+				}
+			}
+		}
+	}
+
+	specg.IDMappings = &conf.IDMappings
+	specg.ContainerCreateCommand = conf.CreateCommand
+	if len(specg.Rootfs) == 0 {
+		specg.Rootfs = conf.Rootfs
+	}
+	if len(specg.Image) == 0 {
+		specg.Image = conf.RootfsImageID
+	}
+	var named []*specgen.NamedVolume
+	if len(conf.NamedVolumes) != 0 {
+		for _, v := range conf.NamedVolumes {
+			named = append(named, &specgen.NamedVolume{
+				Name:    v.Name,
+				Dest:    v.Dest,
+				Options: v.Options,
+			})
+		}
+	}
+	specg.Volumes = named
+	var image []*specgen.ImageVolume
+	if len(conf.ImageVolumes) != 0 {
+		for _, v := range conf.ImageVolumes {
+			image = append(image, &specgen.ImageVolume{
+				Source:      v.Source,
+				Destination: v.Dest,
+				ReadWrite:   v.ReadWrite,
+			})
+		}
+	}
+	specg.ImageVolumes = image
+	var overlay []*specgen.OverlayVolume
+	if len(conf.OverlayVolumes) != 0 {
+		for _, v := range conf.OverlayVolumes {
+			overlay = append(overlay, &specgen.OverlayVolume{
+				Source:      v.Source,
+				Destination: v.Dest,
+				Options:     v.Options,
+			})
+		}
+	}
+	specg.OverlayVolumes = overlay
+	specg.Mounts = conf.Spec.Mounts
+	specg.HostDeviceList = conf.DeviceHostSrc
+	return c, nil
+}