Plugin management utility - plugin stop (#367)

Signed-off-by: David Chung <[email protected]>

Author: David Chung

cmd/cli/plugin.go

@@ -2,8 +2,13 @@ package main
 
 import (
 	"fmt"
+	"io/ioutil"
+	sys_os "os"
+	"strconv"
 	"sync"
+	"syscall"
 
+	log "github.com/Sirupsen/logrus"
 	"github.com/docker/infrakit/pkg/discovery"
 	"github.com/docker/infrakit/pkg/launch"
 	"github.com/docker/infrakit/pkg/launch/os"
@@ -128,7 +133,64 @@ func pluginCommand(plugins func() discovery.Plugins) *cobra.Command {
 		return nil
 	}
 
-	cmd.AddCommand(ls, start)
+	stop := &cobra.Command{
+		Use:   "stop",
+		Short: "Stop named plugins. Args are a list of plugin names.  This assumes plugins are local processes and not containers managed by another daemon, like Docker or runc.",
+	}
+
+	stop.RunE = func(c *cobra.Command, args []string) error {
+
+		allPlugins, err := plugins().List()
+		if err != nil {
+			return err
+		}
+
+		for _, n := range args {
+
+			p, has := allPlugins[n]
+			if !has {
+				log.Warningf("Plugin %s not running", n)
+				continue
+			}
+
+			if p.Protocol != "unix" {
+				log.Warningf("Plugin is not a local process", n)
+				continue
+			}
+
+			// TODO(chungers) -- here we
+			pidFile := p.Address + ".pid"
+
+			buff, err := ioutil.ReadFile(pidFile)
+			if err != nil {
+				log.Warningf("Cannot read PID file for %s: %s", n, pidFile)
+				continue
+			}
+
+			pid, err := strconv.Atoi(string(buff))
+			if err != nil {
+				log.Warningf("Cannot determine PID for %s from file: %s", n, pidFile)
+				continue
+			}
+
+			process, err := sys_os.FindProcess(pid)
+			if err != nil {
+				log.Warningf("Error finding process of plugin %s", n)
+				continue
+			}
+
+			log.Infoln("Stopping", n, "at PID=", pid)
+			if err := process.Signal(syscall.SIGTERM); err == nil {
+				process.Wait()
+				log.Infoln("Process for", n, "exited")
+			}
+
+		}
+
+		return nil
+	}
+
+	cmd.AddCommand(ls, start, stop)
 
 	return cmd
 }

pkg/cli/serverutil.go

@@ -1,6 +1,8 @@
 package cli
 
 import (
+	"fmt"
+	"io/ioutil"
 	"os"
 	"path"
 
@@ -21,11 +23,25 @@ func RunPlugin(name string, plugin server.VersionedInterface) {
 	dir := discovery.Dir()
 	EnsureDirExists(dir)
 
-	stoppable, err := server.StartPluginAtPath(path.Join(dir, name), plugin)
+	socketPath := path.Join(dir, name)
+	pidPath := path.Join(dir, name+".pid")
+
+	stoppable, err := server.StartPluginAtPath(socketPath, plugin)
+	if err != nil {
+		log.Error(err)
+	}
+
+	// write PID file
+	err = ioutil.WriteFile(pidPath, []byte(fmt.Sprintf("%v", os.Getpid())), 0644)
 	if err != nil {
 		log.Error(err)
 	}
+	log.Infoln("PID file at", pidPath)
 	if stoppable != nil {
 		stoppable.AwaitStopped()
 	}
+
+	// clean up
+	os.Remove(pidPath)
+	log.Infoln("Removed PID file at", pidPath)
 }

pkg/discovery/dir.go

@@ -11,6 +11,18 @@ import (
 	"github.com/docker/infrakit/pkg/plugin"
 )
 
+type errNotUnixSocket string
+
+func (e errNotUnixSocket) Error() string {
+	return string(e)
+}
+
+// IsErrNotUnixSocket returns true if the error is due to the file not being a valid unix socket.
+func IsErrNotUnixSocket(e error) bool {
+	_, is := e.(errNotUnixSocket)
+	return is
+}
+
 type dirPluginDiscovery struct {
 	dir  string
 	lock sync.Mutex
@@ -51,7 +63,7 @@ func (r *dirPluginDiscovery) dirLookup(entry os.FileInfo) (*plugin.Endpoint, err
 		}, nil
 	}
 
-	return nil, fmt.Errorf("File is not a socket: %s", entry)
+	return nil, errNotUnixSocket(fmt.Sprintf("File is not a socket: %s", entry))
 }
 
 // List returns a list of plugins known, keyed by the name
@@ -72,8 +84,16 @@ func (r *dirPluginDiscovery) List() (map[string]*plugin.Endpoint, error) {
 		if !entry.IsDir() {
 
 			instance, err := r.dirLookup(entry)
-			if err != nil || instance == nil {
-				log.Warningln("Loading plugin err=", err)
+
+			if err != nil {
+				if !IsErrNotUnixSocket(err) {
+					log.Warningln("Loading plugin err=", err)
+				}
+				continue
+			}
+
+			if instance == nil {
+				log.Warningln("Plugin in nil=")
 				continue
 			}
 

pkg/discovery/dir_test.go

@@ -13,6 +13,12 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func TestErrNotUnixSocket(t *testing.T) {
+	err := errNotUnixSocket("no socket!")
+	require.Error(t, err)
+	require.True(t, IsErrNotUnixSocket(err))
+}
+
 func blockWhileFileExists(name string) {
 	for {
 		_, err := os.Stat(name)

scripts/e2e-test.sh

@@ -142,3 +142,6 @@ infrakit group destroy cattle
 expect_output_lines "0 instances should exist" "infrakit instance describe -q --name instance-file" "0"
 
 echo 'ALL TESTS PASSED'
+
+echo "Stopping plugins"
+infrakit plugin stop group-default instance-file flavor-vanilla