From 23ca2941d21bae10cb561e825a1d7af4d8e0312c Mon Sep 17 00:00:00 2001
From: Anusha Ragunathan <anusha.ragunathan@docker.com>
Date: Fri, 24 Feb 2017 15:35:10 -0800
Subject: [PATCH] Net dial to the plugin socket during enable.

When a plugin fails to start, we still incorrectly mark it as enabled.
This change verifies that we can dial to the plugin socket to confirm that
the plugin is functional and only then mark the plugin as enabled. Also,
dont delete the plugin on install, if only the enable fails.

Signed-off-by: Anusha Ragunathan <anusha.ragunathan@docker.com>
Upstream-commit: 1b41b7a4f4c824bbfdb1acac3e8c8505e0fdb84f
Component: engine
---
 components/engine/client/plugin_install.go |  4 ++--
 components/engine/plugin/manager_linux.go  | 25 +++++++++++++++++++++-
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/components/engine/client/plugin_install.go b/components/engine/client/plugin_install.go
index 33876cc101..ce3e0506e5 100644
--- a/components/engine/client/plugin_install.go
+++ b/components/engine/client/plugin_install.go
@@ -60,8 +60,8 @@ func (cli *Client) PluginInstall(ctx context.Context, name string, options types
 			return
 		}
 
-		err = cli.PluginEnable(ctx, name, types.PluginEnableOptions{Timeout: 0})
-		pw.CloseWithError(err)
+		enableErr := cli.PluginEnable(ctx, name, types.PluginEnableOptions{Timeout: 0})
+		pw.CloseWithError(enableErr)
 	}()
 	return pr, nil
 }
diff --git a/components/engine/plugin/manager_linux.go b/components/engine/plugin/manager_linux.go
index dcc987d9fb..847868f9d3 100644
--- a/components/engine/plugin/manager_linux.go
+++ b/components/engine/plugin/manager_linux.go
@@ -5,6 +5,7 @@ package plugin
 import (
 	"encoding/json"
 	"fmt"
+	"net"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -77,7 +78,8 @@ func (pm *Manager) enable(p *v2.Plugin, c *controller, force bool) error {
 }
 
 func (pm *Manager) pluginPostStart(p *v2.Plugin, c *controller) error {
-	client, err := plugins.NewClientWithTimeout("unix://"+filepath.Join(pm.config.ExecRoot, p.GetID(), p.GetSocket()), nil, c.timeoutInSecs)
+	sockAddr := filepath.Join(pm.config.ExecRoot, p.GetID(), p.GetSocket())
+	client, err := plugins.NewClientWithTimeout("unix://"+sockAddr, nil, c.timeoutInSecs)
 	if err != nil {
 		c.restart = false
 		shutdownPlugin(p, c, pm.containerdClient)
@@ -85,6 +87,27 @@ func (pm *Manager) pluginPostStart(p *v2.Plugin, c *controller) error {
 	}
 
 	p.SetPClient(client)
+
+	maxRetries := 3
+	var retries int
+	for {
+		time.Sleep(3 * time.Second)
+		retries++
+
+		if retries > maxRetries {
+			logrus.Debugf("error net dialing plugin: %v", err)
+			c.restart = false
+			shutdownPlugin(p, c, pm.containerdClient)
+			return err
+		}
+
+		// net dial into the unix socket to see if someone's listening.
+		conn, err := net.Dial("unix", sockAddr)
+		if err == nil {
+			conn.Close()
+			break
+		}
+	}
 	pm.config.Store.SetState(p, true)
 	pm.config.Store.CallHandler(p)