From e18c7fbf8f45a2a86250931fdb4b7f902d82e7e8 Mon Sep 17 00:00:00 2001
From: Nan Deng <dengnan@google.com>
Date: Tue, 17 Jun 2014 15:07:41 -0700
Subject: [PATCH] report error if there's a nil storage driver

---
 manager/container.go | 20 +++++++++++---------
 manager/manager.go   | 37 +++++++++++++++++++------------------
 2 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/manager/container.go b/manager/container.go
index 281e886a..b366c9d6 100644
--- a/manager/container.go
+++ b/manager/container.go
@@ -17,6 +17,7 @@
 package manager
 
 import (
+	"fmt"
 	"log"
 	"sync"
 	"time"
@@ -81,6 +82,9 @@ func (c *containerData) GetInfo() (*containerInfo, error) {
 }
 
 func NewContainerData(containerName string, driver storage.StorageDriver) (*containerData, error) {
+	if driver == nil {
+		return nil, fmt.Errorf("nil storage driver")
+	}
 	cont := &containerData{}
 	handler, err := container.NewContainerHandler(containerName)
 	if err != nil {
@@ -147,15 +151,13 @@ func (c *containerData) updateStats() error {
 	if stats == nil {
 		return nil
 	}
-	if c.storageDriver != nil {
-		ref, err := c.handler.ContainerReference()
-		if err != nil {
-			return err
-		}
-		err = c.storageDriver.AddStats(ref, stats)
-		if err != nil {
-			return err
-		}
+	ref, err := c.handler.ContainerReference()
+	if err != nil {
+		return err
+	}
+	err = c.storageDriver.AddStats(ref, stats)
+	if err != nil {
+		return err
 	}
 	return nil
 }
diff --git a/manager/manager.go b/manager/manager.go
index 26d459b1..1b050355 100644
--- a/manager/manager.go
+++ b/manager/manager.go
@@ -40,6 +40,9 @@ type Manager interface {
 }
 
 func New(driver storage.StorageDriver) (Manager, error) {
+	if driver == nil {
+		return nil, fmt.Errorf("nil storage driver!")
+	}
 	newManager := &manager{}
 	newManager.containers = make(map[string]*containerData)
 
@@ -127,25 +130,23 @@ func (m *manager) GetContainerInfo(containerName string) (*info.ContainerInfo, e
 	var percentiles *info.ContainerStatsPercentiles
 	var samples []*info.ContainerStatsSample
 	var stats []*info.ContainerStats
-	if m.storageDriver != nil {
-		// XXX(monnand): These numbers should not be hard coded
-		percentiles, err = m.storageDriver.Percentiles(
-			cinfo.Name,
-			[]int{50, 80, 90, 99},
-			[]int{50, 80, 90, 99},
-		)
-		if err != nil {
-			return nil, err
-		}
-		samples, err = m.storageDriver.Samples(cinfo.Name, 1024)
-		if err != nil {
-			return nil, err
-		}
+	// TODO(monnand): These numbers should not be hard coded
+	percentiles, err = m.storageDriver.Percentiles(
+		cinfo.Name,
+		[]int{50, 80, 90, 99},
+		[]int{50, 80, 90, 99},
+	)
+	if err != nil {
+		return nil, err
+	}
+	samples, err = m.storageDriver.Samples(cinfo.Name, 1024)
+	if err != nil {
+		return nil, err
+	}
 
-		stats, err = m.storageDriver.RecentStats(cinfo.Name, 1024)
-		if err != nil {
-			return nil, err
-		}
+	stats, err = m.storageDriver.RecentStats(cinfo.Name, 1024)
+	if err != nil {
+		return nil, err
 	}
 
 	// Make a copy of the info for the user.