From 0d2d52339058a19e66ecc75f78c52596054c7dad Mon Sep 17 00:00:00 2001
From: Valentin Rothberg <rothberg@redhat.com>
Date: Mon, 29 Apr 2019 11:21:55 +0200
Subject: top: fallback to execing ps(1)
Fallback to executing ps(1) in case we hit an unknown psgo descriptor.
This ensures backwards compatibility with docker-top, which was purely
ps(1) driven.
Also support comma-separated descriptors as input.
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
---
pkg/adapter/containers.go | 66 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 65 insertions(+), 1 deletion(-)
(limited to 'pkg')
diff --git a/pkg/adapter/containers.go b/pkg/adapter/containers.go
index d575bc9b0..0721af773 100644
--- a/pkg/adapter/containers.go
+++ b/pkg/adapter/containers.go
@@ -3,6 +3,7 @@
package adapter
import (
+ "bufio"
"context"
"fmt"
"io/ioutil"
@@ -19,6 +20,7 @@ import (
"github.com/containers/libpod/libpod"
"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"
@@ -822,7 +824,69 @@ func (r *LocalRuntime) Top(cli *cliconfig.TopValues) ([]string, error) {
if err != nil {
return nil, errors.Wrapf(err, "unable to lookup requested container")
}
- return container.Top(descriptors)
+
+ 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 {
+ // Note: return psgoErr to guide users into using the AIX descriptors
+ // instead of using ps(1).
+ return nil, psgoErr
+ }
+
+ // 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()
+
+ streams := new(libpod.AttachStreams)
+ streams.OutputStream = wPipe
+ streams.ErrorStream = wPipe
+ streams.InputStream = os.Stdin
+ streams.AttachOutput = true
+ streams.AttachError = true
+ streams.AttachInput = true
+
+ psOutput := []string{}
+ go func() {
+ scanner := bufio.NewScanner(rPipe)
+ for scanner.Scan() {
+ psOutput = append(psOutput, scanner.Text())
+ }
+ }()
+
+ cmd := append([]string{"ps"}, args...)
+ if err := c.Exec(false, false, []string{}, cmd, "", "", streams, 0); err != nil {
+ return nil, err
+ }
+
+ return psOutput, nil
}
// Prune removes stopped containers
--
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