refactor top code

Move the top logic from pkg/adapter into the (*libpod.Container).Top().
This way, we drop the dependency from pkg/api on pkg/adapters and have
a clearer separation of concerns.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

libpod/container_top_linux.go

@@ -3,6 +3,8 @@
 package libpod
 
 import (
+	"bufio"
+	"os"
 	"strconv"
 	"strings"
 
@@ -10,6 +12,7 @@ import (
 	"github.com/containers/libpod/pkg/rootless"
 	"github.com/containers/psgo"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 )
 
 // Top gathers statistics about the running processes in a container. It returns a
@@ -36,7 +39,34 @@ func (c *Container) Top(descriptors []string) ([]string, error) {
 			}
 		}
 	}
-	return c.GetContainerPidInformation(psgoDescriptors)
+
+	// If we encountered an ErrUnknownDescriptor error, fallback to executing
+	// ps(1). This ensures backwards compatibility to users depending on ps(1)
+	// and makes sure we're ~compatible with docker.
+	output, psgoErr := c.GetContainerPidInformation(psgoDescriptors)
+	if psgoErr == nil {
+		return output, nil
+	}
+	if errors.Cause(psgoErr) != psgo.ErrUnknownDescriptor {
+		return nil, psgoErr
+	}
+
+	output, err = c.execPS(descriptors)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error executing ps(1) in the container")
+	}
+
+	// Trick: filter the ps command from the output instead of
+	// checking/requiring PIDs in the output.
+	filtered := []string{}
+	cmd := strings.Join(descriptors, " ")
+	for _, line := range output {
+		if !strings.Contains(line, cmd) {
+			filtered = append(filtered, line)
+		}
+	}
+
+	return filtered, nil
 }
 
 // GetContainerPidInformation returns process-related data of all processes in
@@ -65,3 +95,59 @@ func (c *Container) GetContainerPidInformation(descriptors []string) ([]string,
 	}
 	return res, nil
 }
+
+// execPS executes ps(1) with the specified args in the container.
+func (c *Container) execPS(args []string) ([]string, error) {
+	rPipe, wPipe, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
+	defer wPipe.Close()
+	defer rPipe.Close()
+
+	rErrPipe, wErrPipe, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
+	defer wErrPipe.Close()
+	defer rErrPipe.Close()
+
+	streams := new(AttachStreams)
+	streams.OutputStream = wPipe
+	streams.ErrorStream = wErrPipe
+	streams.AttachOutput = true
+	streams.AttachError = true
+
+	stdout := []string{}
+	go func() {
+		scanner := bufio.NewScanner(rPipe)
+		for scanner.Scan() {
+			stdout = append(stdout, scanner.Text())
+		}
+	}()
+	stderr := []string{}
+	go func() {
+		scanner := bufio.NewScanner(rErrPipe)
+		for scanner.Scan() {
+			stderr = append(stderr, scanner.Text())
+		}
+	}()
+
+	cmd := append([]string{"ps"}, args...)
+	ec, err := c.Exec(false, false, map[string]string{}, cmd, "", "", streams, 0, nil, "")
+	if err != nil {
+		return nil, err
+	} else if ec != 0 {
+		return nil, errors.Errorf("Runtime failed with exit status: %d and output: %s", ec, strings.Join(stderr, " "))
+	}
+
+	if logrus.GetLevel() >= logrus.DebugLevel {
+		// If we're running in debug mode or higher, we might want to have a
+		// look at stderr which includes debug logs from conmon.
+		for _, log := range stderr {
+			logrus.Debugf("%s", log)
+		}
+	}
+
+	return stdout, nil
+}

pkg/adapter/containers.go

@@ -27,7 +27,6 @@ import (
 	"github.com/containers/libpod/libpod/logs"
 	"github.com/containers/libpod/pkg/adapter/shortcuts"
 	"github.com/containers/libpod/pkg/systemdgen"
-	"github.com/containers/psgo"
 	"github.com/containers/storage"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -913,89 +912,7 @@ func (r *LocalRuntime) Top(cli *cliconfig.TopValues) ([]string, error) {
 		return nil, errors.Wrapf(err, "unable to lookup requested container")
 	}
 
-	output, psgoErr := container.Top(descriptors)
-	if psgoErr == nil {
-		return output, nil
-	}
-
-	// If we encountered an ErrUnknownDescriptor error, fallback to executing
-	// ps(1). This ensures backwards compatibility to users depending on ps(1)
-	// and makes sure we're ~compatible with docker.
-	if errors.Cause(psgoErr) != psgo.ErrUnknownDescriptor {
-		return nil, psgoErr
-	}
-
-	output, err = r.execPS(container, descriptors)
-	if err != nil {
-		return nil, errors.Wrapf(err, "error executing ps(1) in the container")
-	}
-
-	// Trick: filter the ps command from the output instead of
-	// checking/requiring PIDs in the output.
-	filtered := []string{}
-	cmd := strings.Join(descriptors, " ")
-	for _, line := range output {
-		if !strings.Contains(line, cmd) {
-			filtered = append(filtered, line)
-		}
-	}
-
-	return filtered, nil
-}
-
-func (r *LocalRuntime) execPS(c *libpod.Container, args []string) ([]string, error) {
-	rPipe, wPipe, err := os.Pipe()
-	if err != nil {
-		return nil, err
-	}
-	defer wPipe.Close()
-	defer rPipe.Close()
-
-	rErrPipe, wErrPipe, err := os.Pipe()
-	if err != nil {
-		return nil, err
-	}
-	defer wErrPipe.Close()
-	defer rErrPipe.Close()
-
-	streams := new(libpod.AttachStreams)
-	streams.OutputStream = wPipe
-	streams.ErrorStream = wErrPipe
-	streams.AttachOutput = true
-	streams.AttachError = true
-
-	stdout := []string{}
-	go func() {
-		scanner := bufio.NewScanner(rPipe)
-		for scanner.Scan() {
-			stdout = append(stdout, scanner.Text())
-		}
-	}()
-	stderr := []string{}
-	go func() {
-		scanner := bufio.NewScanner(rErrPipe)
-		for scanner.Scan() {
-			stderr = append(stderr, scanner.Text())
-		}
-	}()
-
-	cmd := append([]string{"ps"}, args...)
-	ec, err := c.Exec(false, false, map[string]string{}, cmd, "", "", streams, 0, nil, "")
-	if err != nil {
-		return nil, err
-	} else if ec != 0 {
-		return nil, errors.Errorf("Runtime failed with exit status: %d and output: %s", ec, strings.Join(stderr, " "))
-	}
-
-	if logrus.GetLevel() >= logrus.DebugLevel {
-		// If we're running in debug mode or higher, we might want to have a
-		// look at stderr which includes debug logs from conmon.
-		for _, log := range stderr {
-			logrus.Debugf("%s", log)
-		}
-	}
-
-	return stdout, nil
+	return container.Top(descriptors)
 }
 
 // ExecContainer executes a command in the container

pkg/api/handlers/containers_top.go

@@ -4,10 +4,7 @@ import (
 	"net/http"
 	"strings"
 
-	"github.com/containers/libpod/cmd/podman/cliconfig"
 	"github.com/containers/libpod/libpod"
-	"github.com/containers/libpod/libpod/define"
-	"github.com/containers/libpod/pkg/adapter"
 	"github.com/containers/libpod/pkg/api/handlers/utils"
 	"github.com/gorilla/mux"
 	"github.com/gorilla/schema"
@@ -30,19 +27,14 @@ func TopContainer(w http.ResponseWriter, r *http.Request) {
 	}
 
 	name := mux.Vars(r)["name"]
-
-	adapterRuntime := adapter.LocalRuntime{}
-	adapterRuntime.Runtime = runtime
-
-	topValues := cliconfig.TopValues{}
-	topValues.InputArgs = []string{name, query.PsArgs}
-
-	output, err := adapterRuntime.Top(&topValues)
+	c, err := runtime.LookupContainer(name)
+	if err != nil {
+		utils.ContainerNotFound(w, name, err)
+		return
+	}
+
+	output, err := c.Top([]string{query.PsArgs})
 	if err != nil {
-		if errors.Cause(err) == define.ErrNoSuchCtr {
-			utils.ContainerNotFound(w, name, err)
-			return
-		}
 		utils.InternalServerError(w, err)
 		return
 	}