podman/libpod/container_top_linux.go
Matthew Heon c2284962c7 Add support for launching containers without CGroups
This is mostly used with Systemd, which really wants to manage
CGroups itself when managing containers via unit file.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>
2019-09-10 10:52:37 -04:00

68 lines
2.2 KiB
Go

// +build linux
package libpod
import (
"strconv"
"strings"
"github.com/containers/libpod/libpod/define"
"github.com/containers/libpod/pkg/rootless"
"github.com/containers/psgo"
"github.com/pkg/errors"
)
// Top gathers statistics about the running processes in a container. It returns a
// []string for output
func (c *Container) Top(descriptors []string) ([]string, error) {
if c.config.NoCgroups {
return nil, errors.Wrapf(define.ErrNoCgroups, "cannot run top on container %s as it did not create a cgroup", c.ID())
}
conStat, err := c.State()
if err != nil {
return nil, errors.Wrapf(err, "unable to look up state for %s", c.ID())
}
if conStat != define.ContainerStateRunning {
return nil, errors.Errorf("top can only be used on running containers")
}
// Also support comma-separated input.
psgoDescriptors := []string{}
for _, d := range descriptors {
for _, s := range strings.Split(d, ",") {
if s != "" {
psgoDescriptors = append(psgoDescriptors, s)
}
}
}
return c.GetContainerPidInformation(psgoDescriptors)
}
// GetContainerPidInformation returns process-related data of all processes in
// the container. The output data can be controlled via the `descriptors`
// argument which expects format descriptors and supports all AIXformat
// descriptors of ps (1) plus some additional ones to for instance inspect the
// set of effective capabilities. Each element in the returned string slice
// is a tab-separated string.
//
// For more details, please refer to github.com/containers/psgo.
func (c *Container) GetContainerPidInformation(descriptors []string) ([]string, error) {
pid := strconv.Itoa(c.state.PID)
// TODO: psgo returns a [][]string to give users the ability to apply
// filters on the data. We need to change the API here and the
// varlink API to return a [][]string if we want to make use of
// filtering.
opts := psgo.JoinNamespaceOpts{FillMappings: rootless.IsRootless()}
psgoOutput, err := psgo.JoinNamespaceAndProcessInfoWithOptions(pid, descriptors, &opts)
if err != nil {
return nil, err
}
res := []string{}
for _, out := range psgoOutput {
res = append(res, strings.Join(out, "\t"))
}
return res, nil
}