kpod top

Display information about processes in a running container.

Signed-off-by: baude <bbaude@redhat.com>

Closes: #121
Approved by: rhatdan

1 files changed, 57 insertions, 0 deletions

diff --git a/libpod/container_top.go b/libpod/container_top.go
new file mode 100644
index 000000000..7d6dad2b4
--- /dev/null
+++ b/libpod/container_top.go
@@ -0,0 +1,57 @@
+package libpod
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+
+	"github.com/pkg/errors"
+	"github.com/projectatomic/libpod/utils"
+	"github.com/sirupsen/logrus"
+)
+
+// GetContainerPids reads sysfs to obtain the pids associated with the container's cgroup
+// and uses locking
+func (c *Container) GetContainerPids() ([]string, error) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return []string{}, errors.Wrapf(err, "error updating container %s state", c.ID())
+	}
+	return c.getContainerPids()
+}
+
+// Gets the pids for a container without locking.  should only be called from a func where
+// locking has already been established.
+func (c *Container) getContainerPids() ([]string, error) {
+	taskFile := filepath.Join("/sys/fs/cgroup/pids", CGroupParent, fmt.Sprintf("libpod-conmon-%s", c.ID()), c.ID(), "tasks")
+	logrus.Debug("reading pids from ", taskFile)
+	content, err := ioutil.ReadFile(taskFile)
+	if err != nil {
+		return []string{}, errors.Wrapf(err, "unable to read pids from %s", taskFile)
+	}
+	return strings.Fields(string(content)), nil
+
+}
+
+// GetContainerPidInformation calls ps with the appropriate options and returns
+// the results as a string
+func (c *Container) GetContainerPidInformation(args []string) ([]string, error) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return []string{}, errors.Wrapf(err, "error updating container %s state", c.ID())
+	}
+	pids, err := c.getContainerPids()
+	if err != nil {
+		return []string{}, errors.Wrapf(err, "unable to obtain pids for ", c.ID())
+	}
+	args = append(args, "-p", strings.Join(pids, ","))
+	logrus.Debug("Executing: ", strings.Join(args, " "))
+	results, err := utils.ExecCmd("ps", args...)
+	if err != nil {
+		return []string{}, errors.Wrapf(err, "unable to obtain information about pids")
+	}
+	return strings.Split(results, "\n"), nil
+}