From 872f921867eadca491876bb2e6ad17d05cf2808a Mon Sep 17 00:00:00 2001
From: Tobias Schmidt <ts@soundcloud.com>
Date: Mon, 24 Nov 2014 21:00:17 -0500
Subject: [PATCH] Reduce number of global variables used

This is the first step to make the exporter more testable.
---
 collector/attributes.go      |  37 +++---
 collector/bonding.go         |  47 +++----
 collector/diskstats.go       | 240 ++++++++++++++++++-----------------
 collector/filesystem.go      | 122 +++++++++---------
 collector/interrupts.go      |  29 ++---
 collector/lastlogin.go       |  25 ++--
 collector/loadavg.go         |  23 ++--
 collector/megacli.go         | 112 ++++++++--------
 collector/meminfo.go         |  23 ++--
 collector/netdev.go          |  23 ++--
 collector/netstat.go         |  23 ++--
 collector/ntp.go             |  19 +--
 collector/runit_collector.go |  85 +++++++------
 collector/stat.go            | 121 +++++++++---------
 collector/time.go            |  24 ++--
 15 files changed, 472 insertions(+), 481 deletions(-)

diff --git a/collector/attributes.go b/collector/attributes.go
index a06d7698..761832bf 100644
--- a/collector/attributes.go
+++ b/collector/attributes.go
@@ -7,12 +7,9 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 )
 
-var (
-	attributes *prometheus.GaugeVec
-)
-
 type attributesCollector struct {
 	config Config
+	metric *prometheus.GaugeVec
 }
 
 func init() {
@@ -22,28 +19,28 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // labels from the config.
 func NewAttributesCollector(config Config) (Collector, error) {
-	c := attributesCollector{
-		config: config,
-	}
 	labelNames := []string{}
-	for l := range c.config.Attributes {
+	for l := range config.Attributes {
 		labelNames = append(labelNames, l)
 	}
-	attributes = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Name:      "attributes",
-			Help:      "The node_exporter attributes.",
-		},
-		labelNames,
-	)
-	return &c, nil
+
+	return &attributesCollector{
+		config: config,
+		metric: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Name:      "attributes",
+				Help:      "The node_exporter attributes.",
+			},
+			labelNames,
+		),
+	}, nil
 }
 
 func (c *attributesCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	glog.V(1).Info("Set node_attributes{%v}: 1", c.config.Attributes)
-	attributes.Reset()
-	attributes.With(c.config.Attributes).Set(1)
-	attributes.Collect(ch)
+	c.metric.Reset()
+	c.metric.With(c.config.Attributes).Set(1)
+	c.metric.Collect(ch)
 	return err
 }
diff --git a/collector/bonding.go b/collector/bonding.go
index 17fd092c..1a132452 100644
--- a/collector/bonding.go
+++ b/collector/bonding.go
@@ -16,22 +16,9 @@ const (
 	sysfsNet = "/sys/class/net"
 )
 
-var (
-	bondingSlaves = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Name:      "net_bonding_slaves",
-			Help:      "Number of configured slaves per bonding interface.",
-		}, []string{"master"})
-	bondingSlavesActive = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Name:      "net_bonding_slaves_active",
-			Help:      "Number of active slaves per bonding interface.",
-		}, []string{"master"})
-)
-
-type bondingCollector struct{}
+type bondingCollector struct {
+	slaves, active *prometheus.GaugeVec
+}
 
 func init() {
 	Factories["bonding"] = NewBondingCollector
@@ -40,8 +27,24 @@ func init() {
 // NewBondingCollector returns a newly allocated bondingCollector.
 // It exposes the number of configured and active slave of linux bonding interfaces.
 func NewBondingCollector(config Config) (Collector, error) {
-	c := bondingCollector{}
-	return &c, nil
+	return &bondingCollector{
+		slaves: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Name:      "net_bonding_slaves",
+				Help:      "Number of configured slaves per bonding interface.",
+			},
+			[]string{"master"},
+		),
+		active: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Name:      "net_bonding_slaves_active",
+				Help:      "Number of active slaves per bonding interface.",
+			},
+			[]string{"master"},
+		),
+	}, nil
 }
 
 // Update reads and exposes bonding states, implements Collector interface. Caution: This works only on linux.
@@ -51,11 +54,11 @@ func (c *bondingCollector) Update(ch chan<- prometheus.Metric) (err error) {
 		return err
 	}
 	for master, status := range bondingStats {
-		bondingSlaves.WithLabelValues(master).Set(float64(status[0]))
-		bondingSlavesActive.WithLabelValues(master).Set(float64(status[1]))
+		c.slaves.WithLabelValues(master).Set(float64(status[0]))
+		c.active.WithLabelValues(master).Set(float64(status[1]))
 	}
-	bondingSlaves.Collect(ch)
-	bondingSlavesActive.Collect(ch)
+	c.slaves.Collect(ch)
+	c.active.Collect(ch)
 	return nil
 }
 
diff --git a/collector/diskstats.go b/collector/diskstats.go
index c6c8d6e7..007446c4 100644
--- a/collector/diskstats.go
+++ b/collector/diskstats.go
@@ -23,116 +23,12 @@ const (
 
 var (
 	ignoredDevices = flag.String("diskstatsIgnoredDevices", "^(ram|loop|(h|s|xv)d[a-z])\\d+$", "Regexp of devices to ignore for diskstats.")
-
-	diskLabelNames = []string{"device"}
-
-	// Docs from https://www.kernel.org/doc/Documentation/iostats.txt
-	diskStatsMetrics = []prometheus.Collector{
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "reads_completed",
-				Help:      "The total number of reads completed successfully.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "reads_merged",
-				Help:      "The number of reads merged. See https://www.kernel.org/doc/Documentation/iostats.txt.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "sectors_read",
-				Help:      "The total number of sectors read successfully.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "read_time_ms",
-				Help:      "The total number of milliseconds spent by all reads.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "writes_completed",
-				Help:      "The total number of writes completed successfully.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "writes_merged",
-				Help:      "The number of writes merged. See https://www.kernel.org/doc/Documentation/iostats.txt.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "sectors_written",
-				Help:      "The total number of sectors written successfully.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "write_time_ms",
-				Help:      "This is the total number of milliseconds spent by all writes.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewGaugeVec(
-			prometheus.GaugeOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "io_now",
-				Help:      "The number of I/Os currently in progress.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "io_time_ms",
-				Help:      "Milliseconds spent doing I/Os.",
-			},
-			diskLabelNames,
-		),
-		prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Namespace: Namespace,
-				Subsystem: diskSubsystem,
-				Name:      "io_time_weighted",
-				Help:      "The weighted # of milliseconds spent doing I/Os. See https://www.kernel.org/doc/Documentation/iostats.txt.",
-			},
-			diskLabelNames,
-		),
-	}
 )
 
 type diskstatsCollector struct {
 	config                Config
 	ignoredDevicesPattern *regexp.Regexp
+	metrics               []prometheus.Collector
 }
 
 func init() {
@@ -142,38 +38,148 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // disk device stats.
 func NewDiskstatsCollector(config Config) (Collector, error) {
-	c := diskstatsCollector{
+	var diskLabelNames = []string{"device"}
+
+	return &diskstatsCollector{
 		config:                config,
 		ignoredDevicesPattern: regexp.MustCompile(*ignoredDevices),
-	}
-	return &c, nil
+		// Docs from https://www.kernel.org/doc/Documentation/iostats.txt
+		metrics: []prometheus.Collector{
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "reads_completed",
+					Help:      "The total number of reads completed successfully.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "reads_merged",
+					Help:      "The number of reads merged. See https://www.kernel.org/doc/Documentation/iostats.txt.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "sectors_read",
+					Help:      "The total number of sectors read successfully.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "read_time_ms",
+					Help:      "The total number of milliseconds spent by all reads.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "writes_completed",
+					Help:      "The total number of writes completed successfully.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "writes_merged",
+					Help:      "The number of writes merged. See https://www.kernel.org/doc/Documentation/iostats.txt.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "sectors_written",
+					Help:      "The total number of sectors written successfully.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "write_time_ms",
+					Help:      "This is the total number of milliseconds spent by all writes.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewGaugeVec(
+				prometheus.GaugeOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "io_now",
+					Help:      "The number of I/Os currently in progress.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "io_time_ms",
+					Help:      "Milliseconds spent doing I/Os.",
+				},
+				diskLabelNames,
+			),
+			prometheus.NewCounterVec(
+				prometheus.CounterOpts{
+					Namespace: Namespace,
+					Subsystem: diskSubsystem,
+					Name:      "io_time_weighted",
+					Help:      "The weighted # of milliseconds spent doing I/Os. See https://www.kernel.org/doc/Documentation/iostats.txt.",
+				},
+				diskLabelNames,
+			),
+		},
+	}, nil
 }
 
 func (c *diskstatsCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	diskStats, err := getDiskStats()
 	if err != nil {
-		return fmt.Errorf("Couldn't get diskstats: %s", err)
+		return fmt.Errorf("couldn't get diskstats: %s", err)
 	}
+
 	for dev, stats := range diskStats {
 		if c.ignoredDevicesPattern.MatchString(dev) {
 			glog.V(1).Infof("Ignoring device: %s", dev)
 			continue
 		}
+
+		if len(stats) != len(c.metrics) {
+			return fmt.Errorf("invalid line for %s for %s", procDiskStats, dev)
+		}
+
 		for k, value := range stats {
 			v, err := strconv.ParseFloat(value, 64)
 			if err != nil {
-				return fmt.Errorf("Invalid value %s in diskstats: %s", value, err)
+				return fmt.Errorf("invalid value %s in diskstats: %s", value, err)
 			}
-			counter, ok := diskStatsMetrics[k].(*prometheus.CounterVec)
-			if ok {
+
+			if counter, ok := c.metrics[k].(*prometheus.CounterVec); ok {
 				counter.WithLabelValues(dev).Set(v)
-			} else {
-				var gauge = diskStatsMetrics[k].(*prometheus.GaugeVec)
+			} else if gauge, ok := c.metrics[k].(*prometheus.GaugeVec); ok {
 				gauge.WithLabelValues(dev).Set(v)
+			} else {
+				return fmt.Errorf("unexpected collector %d", k)
 			}
 		}
 	}
-	for _, c := range diskStatsMetrics {
+	for _, c := range c.metrics {
 		c.Collect(ch)
 	}
 	return err
@@ -197,8 +203,8 @@ func parseDiskStats(r io.Reader) (map[string]map[int]string, error) {
 
 	for scanner.Scan() {
 		parts := strings.Fields(string(scanner.Text()))
-		if len(parts) != len(diskStatsMetrics)+3 { // we strip major, minor and dev
-			return nil, fmt.Errorf("Invalid line in %s: %s", procDiskStats, scanner.Text())
+		if len(parts) < 4 { // we strip major, minor and dev
+			return nil, fmt.Errorf("invalid line in %s: %s", procDiskStats, scanner.Text())
 		}
 		dev := parts[2]
 		diskStats[dev] = map[int]string{}
diff --git a/collector/filesystem.go b/collector/filesystem.go
index c7dca3fc..fa618aab 100644
--- a/collector/filesystem.go
+++ b/collector/filesystem.go
@@ -21,60 +21,14 @@ const (
 )
 
 var (
-	filesystemLabelNames = []string{"filesystem"}
-
-	fsSizeMetric = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Subsystem: filesystemSubsystem,
-			Name:      "size",
-			Help:      "Filesystem size in bytes.",
-		},
-		filesystemLabelNames,
-	)
-	fsFreeMetric = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Subsystem: filesystemSubsystem,
-			Name:      "free",
-			Help:      "Filesystem free space in bytes.",
-		},
-		filesystemLabelNames,
-	)
-	fsAvailMetric = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Subsystem: filesystemSubsystem,
-			Name:      "avail",
-			Help:      "Filesystem space available to non-root users in bytes.",
-		},
-		filesystemLabelNames,
-	)
-	fsFilesMetric = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Subsystem: filesystemSubsystem,
-			Name:      "files",
-			Help:      "Filesystem total file nodes.",
-		},
-		filesystemLabelNames,
-	)
-	fsFilesFreeMetric = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Subsystem: filesystemSubsystem,
-			Name:      "files_free",
-			Help:      "Filesystem total free file nodes.",
-		},
-		filesystemLabelNames,
-	)
-
 	ignoredMountPoints = flag.String("filesystemIgnoredMountPoints", "^/(sys|proc|dev)($|/)", "Regexp of mount points to ignore for filesystem collector.")
 )
 
 type filesystemCollector struct {
 	config                    Config
 	ignoredMountPointsPattern *regexp.Regexp
+
+	size, free, avail, files, filesFree *prometheus.GaugeVec
 }
 
 func init() {
@@ -84,11 +38,57 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // network device filesystems.
 func NewFilesystemCollector(config Config) (Collector, error) {
-	c := filesystemCollector{
+	var filesystemLabelNames = []string{"filesystem"}
+
+	return &filesystemCollector{
 		config: config,
 		ignoredMountPointsPattern: regexp.MustCompile(*ignoredMountPoints),
-	}
-	return &c, nil
+		size: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: filesystemSubsystem,
+				Name:      "size",
+				Help:      "Filesystem size in bytes.",
+			},
+			filesystemLabelNames,
+		),
+		free: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: filesystemSubsystem,
+				Name:      "free",
+				Help:      "Filesystem free space in bytes.",
+			},
+			filesystemLabelNames,
+		),
+		avail: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: filesystemSubsystem,
+				Name:      "avail",
+				Help:      "Filesystem space available to non-root users in bytes.",
+			},
+			filesystemLabelNames,
+		),
+		files: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: filesystemSubsystem,
+				Name:      "files",
+				Help:      "Filesystem total file nodes.",
+			},
+			filesystemLabelNames,
+		),
+		filesFree: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: filesystemSubsystem,
+				Name:      "files_free",
+				Help:      "Filesystem total free file nodes.",
+			},
+			filesystemLabelNames,
+		),
+	}, nil
 }
 
 // Expose filesystem fullness.
@@ -107,17 +107,17 @@ func (c *filesystemCollector) Update(ch chan<- prometheus.Metric) (err error) {
 		if err != nil {
 			return fmt.Errorf("Statfs on %s returned %s", mp, err)
 		}
-		fsSizeMetric.WithLabelValues(mp).Set(float64(buf.Blocks) * float64(buf.Bsize))
-		fsFreeMetric.WithLabelValues(mp).Set(float64(buf.Bfree) * float64(buf.Bsize))
-		fsAvailMetric.WithLabelValues(mp).Set(float64(buf.Bavail) * float64(buf.Bsize))
-		fsFilesMetric.WithLabelValues(mp).Set(float64(buf.Files))
-		fsFilesFreeMetric.WithLabelValues(mp).Set(float64(buf.Ffree))
+		c.size.WithLabelValues(mp).Set(float64(buf.Blocks) * float64(buf.Bsize))
+		c.free.WithLabelValues(mp).Set(float64(buf.Bfree) * float64(buf.Bsize))
+		c.avail.WithLabelValues(mp).Set(float64(buf.Bavail) * float64(buf.Bsize))
+		c.files.WithLabelValues(mp).Set(float64(buf.Files))
+		c.filesFree.WithLabelValues(mp).Set(float64(buf.Ffree))
 	}
-	fsSizeMetric.Collect(ch)
-	fsFreeMetric.Collect(ch)
-	fsAvailMetric.Collect(ch)
-	fsFilesMetric.Collect(ch)
-	fsFilesFreeMetric.Collect(ch)
+	c.size.Collect(ch)
+	c.free.Collect(ch)
+	c.avail.Collect(ch)
+	c.files.Collect(ch)
+	c.filesFree.Collect(ch)
 	return err
 }
 
diff --git a/collector/interrupts.go b/collector/interrupts.go
index 48a26602..74c98e9d 100644
--- a/collector/interrupts.go
+++ b/collector/interrupts.go
@@ -17,19 +17,9 @@ const (
 	procInterrupts = "/proc/interrupts"
 )
 
-var (
-	interruptsMetric = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Namespace: Namespace,
-			Name:      "interrupts",
-			Help:      "Interrupt details from /proc/interrupts.",
-		},
-		[]string{"CPU", "type", "info", "devices"},
-	)
-)
-
 type interruptsCollector struct {
 	config Config
+	metric *prometheus.CounterVec
 }
 
 func init() {
@@ -39,10 +29,17 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // interrupts stats
 func NewInterruptsCollector(config Config) (Collector, error) {
-	c := interruptsCollector{
+	return &interruptsCollector{
 		config: config,
-	}
-	return &c, nil
+		metric: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: Namespace,
+				Name:      "interrupts",
+				Help:      "Interrupt details from /proc/interrupts.",
+			},
+			[]string{"CPU", "type", "info", "devices"},
+		),
+	}, nil
 }
 
 func (c *interruptsCollector) Update(ch chan<- prometheus.Metric) (err error) {
@@ -62,10 +59,10 @@ func (c *interruptsCollector) Update(ch chan<- prometheus.Metric) (err error) {
 				"info":    interrupt.info,
 				"devices": interrupt.devices,
 			}
-			interruptsMetric.With(labels).Set(fv)
+			c.metric.With(labels).Set(fv)
 		}
 	}
-	interruptsMetric.Collect(ch)
+	c.metric.Collect(ch)
 	return err
 }
 
diff --git a/collector/lastlogin.go b/collector/lastlogin.go
index 48fbab1b..970a8238 100644
--- a/collector/lastlogin.go
+++ b/collector/lastlogin.go
@@ -16,17 +16,9 @@ import (
 
 const lastLoginSubsystem = "last_login"
 
-var (
-	lastSeen = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Subsystem: lastLoginSubsystem,
-		Name:      "time",
-		Help:      "The time of the last login.",
-	})
-)
-
 type lastLoginCollector struct {
 	config Config
+	metric prometheus.Gauge
 }
 
 func init() {
@@ -36,10 +28,15 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // load, seconds since last login and a list of tags as specified by config.
 func NewLastLoginCollector(config Config) (Collector, error) {
-	c := lastLoginCollector{
+	return &lastLoginCollector{
 		config: config,
-	}
-	return &c, nil
+		metric: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Subsystem: lastLoginSubsystem,
+			Name:      "time",
+			Help:      "The time of the last login.",
+		}),
+	}, nil
 }
 
 func (c *lastLoginCollector) Update(ch chan<- prometheus.Metric) (err error) {
@@ -48,8 +45,8 @@ func (c *lastLoginCollector) Update(ch chan<- prometheus.Metric) (err error) {
 		return fmt.Errorf("Couldn't get last seen: %s", err)
 	}
 	glog.V(1).Infof("Set node_last_login_time: %f", last)
-	lastSeen.Set(last)
-	lastSeen.Collect(ch)
+	c.metric.Set(last)
+	c.metric.Collect(ch)
 	return err
 }
 
diff --git a/collector/loadavg.go b/collector/loadavg.go
index b4ab9d41..6b157d2f 100644
--- a/collector/loadavg.go
+++ b/collector/loadavg.go
@@ -16,16 +16,9 @@ const (
 	procLoad = "/proc/loadavg"
 )
 
-var (
-	load1 = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "load1",
-		Help:      "1m load average.",
-	})
-)
-
 type loadavgCollector struct {
 	config Config
+	metric prometheus.Gauge
 }
 
 func init() {
@@ -35,10 +28,14 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // load, seconds since last login and a list of tags as specified by config.
 func NewLoadavgCollector(config Config) (Collector, error) {
-	c := loadavgCollector{
+	return &loadavgCollector{
 		config: config,
-	}
-	return &c, nil
+		metric: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "load1",
+			Help:      "1m load average.",
+		}),
+	}, nil
 }
 
 func (c *loadavgCollector) Update(ch chan<- prometheus.Metric) (err error) {
@@ -47,8 +44,8 @@ func (c *loadavgCollector) Update(ch chan<- prometheus.Metric) (err error) {
 		return fmt.Errorf("Couldn't get load: %s", err)
 	}
 	glog.V(1).Infof("Set node_load: %f", load)
-	load1.Set(load)
-	load1.Collect(ch)
+	c.metric.Set(load)
+	c.metric.Collect(ch)
 	return err
 }
 
diff --git a/collector/megacli.go b/collector/megacli.go
index 6025c99b..404d31a5 100644
--- a/collector/megacli.go
+++ b/collector/megacli.go
@@ -17,32 +17,60 @@ const (
 	adapterHeaderSep = "================"
 )
 
-var (
-	driveTemperature = prometheus.NewGaugeVec(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "megacli_drive_temperature_celsius",
-		Help:      "megacli: drive temperature",
-	}, []string{"enclosure", "slot"})
+type megaCliCollector struct {
+	config Config
+	cli    string
 
-	driveCounters = prometheus.NewCounterVec(prometheus.CounterOpts{
-		Namespace: Namespace,
-		Name:      "megacli_drive_count",
-		Help:      "megacli: drive error and event counters",
-	}, []string{"enclosure", "slot", "type"})
-
-	drivePresence = prometheus.NewGaugeVec(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "megacli_adapter_disk_presence",
-		Help:      "megacli: disk presence per adapter",
-	}, []string{"type"})
-
-	counters = []string{"Media Error Count", "Other Error Count", "Predictive Failure Count"}
-)
+	driveTemperature *prometheus.GaugeVec
+	driveCounters    *prometheus.CounterVec
+	drivePresence    *prometheus.GaugeVec
+}
 
 func init() {
 	Factories["megacli"] = NewMegaCliCollector
 }
 
+// Takes a config struct and prometheus registry and returns a new Collector exposing
+// RAID status through megacli.
+func NewMegaCliCollector(config Config) (Collector, error) {
+	cli := defaultMegaCli
+	if config.Config["megacli_command"] != "" {
+		cli = config.Config["megacli_command"]
+	}
+
+	return &megaCliCollector{
+		config: config,
+		cli:    cli,
+		driveTemperature: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "megacli_drive_temperature_celsius",
+			Help:      "megacli: drive temperature",
+		}, []string{"enclosure", "slot"}),
+		driveCounters: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Namespace: Namespace,
+			Name:      "megacli_drive_count",
+			Help:      "megacli: drive error and event counters",
+		}, []string{"enclosure", "slot", "type"}),
+		drivePresence: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "megacli_adapter_disk_presence",
+			Help:      "megacli: disk presence per adapter",
+		}, []string{"type"}),
+	}, nil
+}
+
+func (c *megaCliCollector) Update(ch chan<- prometheus.Metric) (err error) {
+	err = c.updateAdapter()
+	if err != nil {
+		return err
+	}
+	err = c.updateDisks()
+	c.driveTemperature.Collect(ch)
+	c.driveCounters.Collect(ch)
+	c.drivePresence.Collect(ch)
+	return err
+}
+
 func parseMegaCliDisks(r io.Reader) (map[int]map[int]map[string]string, error) {
 	var (
 		stats   = map[int]map[int]map[string]string{}
@@ -118,38 +146,6 @@ func parseMegaCliAdapter(r io.Reader) (map[string]map[string]string, error) {
 	return raidStats, nil
 }
 
-type megaCliCollector struct {
-	config Config
-	cli    string
-}
-
-// Takes a config struct and prometheus registry and returns a new Collector exposing
-// RAID status through megacli.
-func NewMegaCliCollector(config Config) (Collector, error) {
-	cli := defaultMegaCli
-	if config.Config["megacli_command"] != "" {
-		cli = config.Config["megacli_command"]
-	}
-
-	c := megaCliCollector{
-		config: config,
-		cli:    cli,
-	}
-	return &c, nil
-}
-
-func (c *megaCliCollector) Update(ch chan<- prometheus.Metric) (err error) {
-	err = c.updateAdapter()
-	if err != nil {
-		return err
-	}
-	err = c.updateDisks()
-	driveTemperature.Collect(ch)
-	driveCounters.Collect(ch)
-	drivePresence.Collect(ch)
-	return err
-}
-
 func (c *megaCliCollector) updateAdapter() error {
 	cmd := exec.Command(c.cli, "-AdpAllInfo", "-aALL")
 	pipe, err := cmd.StdoutPipe()
@@ -174,12 +170,14 @@ func (c *megaCliCollector) updateAdapter() error {
 		if err != nil {
 			return err
 		}
-		drivePresence.WithLabelValues(k).Set(value)
+		c.drivePresence.WithLabelValues(k).Set(value)
 	}
 	return nil
 }
 
 func (c *megaCliCollector) updateDisks() error {
+	var counters = []string{"Media Error Count", "Other Error Count", "Predictive Failure Count"}
+
 	cmd := exec.Command(c.cli, "-PDList", "-aALL")
 	pipe, err := cmd.StdoutPipe()
 	if err != nil {
@@ -210,15 +208,15 @@ func (c *megaCliCollector) updateDisks() error {
 			encStr := strconv.Itoa(enc)
 			slotStr := strconv.Itoa(slot)
 
-			driveTemperature.WithLabelValues(encStr, slotStr).Set(t)
+			c.driveTemperature.WithLabelValues(encStr, slotStr).Set(t)
 
-			for _, c := range counters {
-				counter, err := strconv.ParseFloat(slotStats[c], 64)
+			for _, i := range counters {
+				counter, err := strconv.ParseFloat(slotStats[i], 64)
 				if err != nil {
 					return err
 				}
 
-				driveCounters.WithLabelValues(encStr, slotStr, c).Set(counter)
+				c.driveCounters.WithLabelValues(encStr, slotStr, i).Set(counter)
 			}
 		}
 	}
diff --git a/collector/meminfo.go b/collector/meminfo.go
index 13d2e179..58a6e70b 100644
--- a/collector/meminfo.go
+++ b/collector/meminfo.go
@@ -20,12 +20,9 @@ const (
 	memInfoSubsystem = "memory"
 )
 
-var (
-	memInfoMetrics = map[string]prometheus.Gauge{}
-)
-
 type meminfoCollector struct {
-	config Config
+	config  Config
+	metrics map[string]prometheus.Gauge
 }
 
 func init() {
@@ -35,10 +32,10 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // memory stats.
 func NewMeminfoCollector(config Config) (Collector, error) {
-	c := meminfoCollector{
-		config: config,
-	}
-	return &c, nil
+	return &meminfoCollector{
+		config:  config,
+		metrics: map[string]prometheus.Gauge{},
+	}, nil
 }
 
 func (c *meminfoCollector) Update(ch chan<- prometheus.Metric) (err error) {
@@ -48,16 +45,16 @@ func (c *meminfoCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	}
 	glog.V(1).Infof("Set node_mem: %#v", memInfo)
 	for k, v := range memInfo {
-		if _, ok := memInfoMetrics[k]; !ok {
-			memInfoMetrics[k] = prometheus.NewGauge(prometheus.GaugeOpts{
+		if _, ok := c.metrics[k]; !ok {
+			c.metrics[k] = prometheus.NewGauge(prometheus.GaugeOpts{
 				Namespace: Namespace,
 				Subsystem: memInfoSubsystem,
 				Name:      k,
 				Help:      k + " from /proc/meminfo.",
 			})
 		}
-		memInfoMetrics[k].Set(v)
-		memInfoMetrics[k].Collect(ch)
+		c.metrics[k].Set(v)
+		c.metrics[k].Collect(ch)
 	}
 	return err
 }
diff --git a/collector/netdev.go b/collector/netdev.go
index efc27711..e8a658b9 100644
--- a/collector/netdev.go
+++ b/collector/netdev.go
@@ -18,12 +18,9 @@ const (
 	netDevSubsystem = "network"
 )
 
-var (
-	netDevMetrics = map[string]*prometheus.GaugeVec{}
-)
-
 type netDevCollector struct {
-	config Config
+	config  Config
+	metrics map[string]*prometheus.GaugeVec
 }
 
 func init() {
@@ -33,10 +30,10 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // network device stats.
 func NewNetDevCollector(config Config) (Collector, error) {
-	c := netDevCollector{
-		config: config,
-	}
-	return &c, nil
+	return &netDevCollector{
+		config:  config,
+		metrics: map[string]*prometheus.GaugeVec{},
+	}, nil
 }
 
 func (c *netDevCollector) Update(ch chan<- prometheus.Metric) (err error) {
@@ -48,8 +45,8 @@ func (c *netDevCollector) Update(ch chan<- prometheus.Metric) (err error) {
 		for dev, stats := range devStats {
 			for t, value := range stats {
 				key := direction + "_" + t
-				if _, ok := netDevMetrics[key]; !ok {
-					netDevMetrics[key] = prometheus.NewGaugeVec(
+				if _, ok := c.metrics[key]; !ok {
+					c.metrics[key] = prometheus.NewGaugeVec(
 						prometheus.GaugeOpts{
 							Namespace: Namespace,
 							Subsystem: netDevSubsystem,
@@ -63,11 +60,11 @@ func (c *netDevCollector) Update(ch chan<- prometheus.Metric) (err error) {
 				if err != nil {
 					return fmt.Errorf("Invalid value %s in netstats: %s", value, err)
 				}
-				netDevMetrics[key].WithLabelValues(dev).Set(v)
+				c.metrics[key].WithLabelValues(dev).Set(v)
 			}
 		}
 	}
-	for _, m := range netDevMetrics {
+	for _, m := range c.metrics {
 		m.Collect(ch)
 	}
 	return err
diff --git a/collector/netstat.go b/collector/netstat.go
index bca6dcd8..19948c20 100644
--- a/collector/netstat.go
+++ b/collector/netstat.go
@@ -18,12 +18,9 @@ const (
 	netStatsSubsystem = "netstat"
 )
 
-var (
-	netStatsMetrics = map[string]prometheus.Gauge{}
-)
-
 type netStatCollector struct {
-	config Config
+	config  Config
+	metrics map[string]prometheus.Gauge
 }
 
 func init() {
@@ -33,10 +30,10 @@ func init() {
 // NewNetStatCollector takes a config struct and returns
 // a new Collector exposing network stats.
 func NewNetStatCollector(config Config) (Collector, error) {
-	c := netStatCollector{
-		config: config,
-	}
-	return &c, nil
+	return &netStatCollector{
+		config:  config,
+		metrics: map[string]prometheus.Gauge{},
+	}, nil
 }
 
 func (c *netStatCollector) Update(ch chan<- prometheus.Metric) (err error) {
@@ -47,8 +44,8 @@ func (c *netStatCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	for protocol, protocolStats := range netStats {
 		for name, value := range protocolStats {
 			key := protocol + "_" + name
-			if _, ok := netStatsMetrics[key]; !ok {
-				netStatsMetrics[key] = prometheus.NewGauge(
+			if _, ok := c.metrics[key]; !ok {
+				c.metrics[key] = prometheus.NewGauge(
 					prometheus.GaugeOpts{
 						Namespace: Namespace,
 						Subsystem: netStatsSubsystem,
@@ -61,10 +58,10 @@ func (c *netStatCollector) Update(ch chan<- prometheus.Metric) (err error) {
 			if err != nil {
 				return fmt.Errorf("invalid value %s in netstats: %s", value, err)
 			}
-			netStatsMetrics[key].Set(v)
+			c.metrics[key].Set(v)
 		}
 	}
-	for _, m := range netStatsMetrics {
+	for _, m := range c.metrics {
 		m.Collect(ch)
 	}
 	return err
diff --git a/collector/ntp.go b/collector/ntp.go
index f2b9b676..1172ff79 100644
--- a/collector/ntp.go
+++ b/collector/ntp.go
@@ -14,14 +14,10 @@ import (
 
 var (
 	ntpServer = flag.String("ntpServer", "", "NTP server to use for ntp collector.")
-	ntpDrift  = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "ntp_drift_seconds",
-		Help:      "Time between system time and ntp time.",
-	})
 )
 
 type ntpCollector struct {
+	drift prometheus.Gauge
 }
 
 func init() {
@@ -34,9 +30,14 @@ func NewNtpCollector(config Config) (Collector, error) {
 	if *ntpServer == "" {
 		return nil, fmt.Errorf("No NTP server specifies, see --ntpServer")
 	}
-	c := ntpCollector{}
 
-	return &c, nil
+	return &ntpCollector{
+		drift: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "ntp_drift_seconds",
+			Help:      "Time between system time and ntp time.",
+		}),
+	}, nil
 }
 
 func (c *ntpCollector) Update(ch chan<- prometheus.Metric) (err error) {
@@ -46,7 +47,7 @@ func (c *ntpCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	}
 	drift := t.Sub(time.Now())
 	glog.V(1).Infof("Set ntp_drift_seconds: %f", drift.Seconds())
-	ntpDrift.Set(drift.Seconds())
-	ntpDrift.Collect(ch)
+	c.drift.Set(drift.Seconds())
+	c.drift.Collect(ch)
 	return err
 }
diff --git a/collector/runit_collector.go b/collector/runit_collector.go
index b71d2aff..9ae78f5e 100644
--- a/collector/runit_collector.go
+++ b/collector/runit_collector.go
@@ -8,37 +8,14 @@ import (
 	"github.com/soundcloud/go-runit/runit"
 )
 
-var (
-	runitLabelNames = []string{"service"}
-
-	runitState = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Name:      "service_state",
-			Help:      "node_exporter: state of runit service.",
-		},
-		runitLabelNames,
-	)
-	runitStateDesired = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Name:      "service_desired_state",
-			Help:      "node_exporter: desired state of runit service.",
-		},
-		runitLabelNames,
-	)
-	runitStateNormal = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: Namespace,
-			Name:      "service_normal_state",
-			Help:      "node_exporter: normal state of runit service.",
-		},
-		runitLabelNames,
-	)
+const (
+	runitSubsystem = "runit"
 )
 
 type runitCollector struct {
 	config Config
+
+	state, stateDesired, stateNormal *prometheus.GaugeVec
 }
 
 func init() {
@@ -46,14 +23,41 @@ func init() {
 }
 
 func NewRunitCollector(config Config) (Collector, error) {
-	c := runitCollector{
-		config: config,
-	}
+	var labels = []string{"service"}
 
-	return &c, nil
+	return &runitCollector{
+		config: config,
+		state: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: runitSubsystem,
+				Name:      "state",
+				Help:      "state of runit service.",
+			},
+			labels,
+		),
+		stateDesired: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: runitSubsystem,
+				Name:      "desired_state",
+				Help:      "desired state of runit service.",
+			},
+			labels,
+		),
+		stateNormal: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: Namespace,
+				Subsystem: runitSubsystem,
+				Name:      "normal_state",
+				Help:      "normal state of runit service.",
+			},
+			labels,
+		),
+	}, nil
 }
 
-func (c *runitCollector) Update(ch chan<- prometheus.Metric) (err error) {
+func (c *runitCollector) Update(ch chan<- prometheus.Metric) error {
 	services, err := runit.GetServices("/etc/service")
 	if err != nil {
 		return err
@@ -67,16 +71,17 @@ func (c *runitCollector) Update(ch chan<- prometheus.Metric) (err error) {
 		}
 
 		glog.V(1).Infof("%s is %d on pid %d for %d seconds", service.Name, status.State, status.Pid, status.Duration)
-		runitState.WithLabelValues(service.Name).Set(float64(status.State))
-		runitStateDesired.WithLabelValues(service.Name).Set(float64(status.Want))
+		c.state.WithLabelValues(service.Name).Set(float64(status.State))
+		c.stateDesired.WithLabelValues(service.Name).Set(float64(status.Want))
 		if status.NormallyUp {
-			runitStateNormal.WithLabelValues(service.Name).Set(1)
+			c.stateNormal.WithLabelValues(service.Name).Set(1)
 		} else {
-			runitStateNormal.WithLabelValues(service.Name).Set(1)
+			c.stateNormal.WithLabelValues(service.Name).Set(0)
 		}
 	}
-	runitState.Collect(ch)
-	runitStateDesired.Collect(ch)
-	runitStateNormal.Collect(ch)
-	return err
+	c.state.Collect(ch)
+	c.stateDesired.Collect(ch)
+	c.stateNormal.Collect(ch)
+
+	return nil
 }
diff --git a/collector/stat.go b/collector/stat.go
index 4e78f9c4..f5942f9e 100644
--- a/collector/stat.go
+++ b/collector/stat.go
@@ -18,49 +18,15 @@ const (
 	procStat = "/proc/stat"
 )
 
-var (
-	cpuMetrics = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Namespace: Namespace,
-			Name:      "cpu",
-			Help:      "Seconds the cpus spent in each mode.",
-		},
-		[]string{"cpu", "mode"},
-	)
-	intrMetric = prometheus.NewCounter(prometheus.CounterOpts{
-		Namespace: Namespace,
-		Name:      "intr",
-		Help:      "Total number of interrupts serviced.",
-	})
-	ctxtMetric = prometheus.NewCounter(prometheus.CounterOpts{
-		Namespace: Namespace,
-		Name:      "context_switches",
-		Help:      "Total number of context switches.",
-	})
-	forksMetric = prometheus.NewCounter(prometheus.CounterOpts{
-		Namespace: Namespace,
-		Name:      "forks",
-		Help:      "Total number of forks.",
-	})
-	btimeMetric = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "boot_time",
-		Help:      "Node boot time, in unixtime.",
-	})
-	procsRunningMetric = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "procs_running",
-		Help:      "Number of processes in runnable state.",
-	})
-	procsBlockedMetric = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: Namespace,
-		Name:      "procs_blocked",
-		Help:      "Number of processes blocked waiting for I/O to complete.",
-	})
-)
-
 type statCollector struct {
-	config Config
+	config       Config
+	cpu          *prometheus.CounterVec
+	intr         prometheus.Counter
+	ctxt         prometheus.Counter
+	forks        prometheus.Counter
+	btime        prometheus.Gauge
+	procsRunning prometheus.Gauge
+	procsBlocked prometheus.Gauge
 }
 
 func init() {
@@ -70,10 +36,47 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // network device stats.
 func NewStatCollector(config Config) (Collector, error) {
-	c := statCollector{
+	return &statCollector{
 		config: config,
-	}
-	return &c, nil
+		cpu: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: Namespace,
+				Name:      "cpu",
+				Help:      "Seconds the cpus spent in each mode.",
+			},
+			[]string{"cpu", "mode"},
+		),
+		intr: prometheus.NewCounter(prometheus.CounterOpts{
+			Namespace: Namespace,
+			Name:      "intr",
+			Help:      "Total number of interrupts serviced.",
+		}),
+		ctxt: prometheus.NewCounter(prometheus.CounterOpts{
+			Namespace: Namespace,
+			Name:      "context_switches",
+			Help:      "Total number of context switches.",
+		}),
+		forks: prometheus.NewCounter(prometheus.CounterOpts{
+			Namespace: Namespace,
+			Name:      "forks",
+			Help:      "Total number of forks.",
+		}),
+		btime: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "boot_time",
+			Help:      "Node boot time, in unixtime.",
+		}),
+		procsRunning: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "procs_running",
+			Help:      "Number of processes in runnable state.",
+		}),
+		procsBlocked: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: Namespace,
+			Name:      "procs_blocked",
+			Help:      "Number of processes blocked waiting for I/O to complete.",
+		}),
+	}, nil
 }
 
 // Expose a variety of stats from /proc/stats.
@@ -102,7 +105,7 @@ func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
 				}
 				// Convert from ticks to seconds
 				value /= float64(C.sysconf(C._SC_CLK_TCK))
-				cpuMetrics.With(prometheus.Labels{"cpu": parts[0], "mode": cpuFields[i]}).Set(value)
+				c.cpu.With(prometheus.Labels{"cpu": parts[0], "mode": cpuFields[i]}).Set(value)
 			}
 		case parts[0] == "intr":
 			// Only expose the overall number, use the 'interrupts' collector for more detail.
@@ -110,45 +113,45 @@ func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
 			if err != nil {
 				return err
 			}
-			intrMetric.Set(value)
+			c.intr.Set(value)
 		case parts[0] == "ctxt":
 			value, err := strconv.ParseFloat(parts[1], 64)
 			if err != nil {
 				return err
 			}
-			ctxtMetric.Set(value)
+			c.ctxt.Set(value)
 		case parts[0] == "processes":
 			value, err := strconv.ParseFloat(parts[1], 64)
 			if err != nil {
 				return err
 			}
-			forksMetric.Set(value)
+			c.forks.Set(value)
 		case parts[0] == "btime":
 			value, err := strconv.ParseFloat(parts[1], 64)
 			if err != nil {
 				return err
 			}
-			btimeMetric.Set(value)
+			c.btime.Set(value)
 		case parts[0] == "procs_running":
 			value, err := strconv.ParseFloat(parts[1], 64)
 			if err != nil {
 				return err
 			}
-			procsRunningMetric.Set(value)
+			c.procsRunning.Set(value)
 		case parts[0] == "procs_blocked":
 			value, err := strconv.ParseFloat(parts[1], 64)
 			if err != nil {
 				return err
 			}
-			procsBlockedMetric.Set(value)
+			c.procsBlocked.Set(value)
 		}
 	}
-	cpuMetrics.Collect(ch)
-	ctxtMetric.Collect(ch)
-	intrMetric.Collect(ch)
-	forksMetric.Collect(ch)
-	btimeMetric.Collect(ch)
-	procsRunningMetric.Collect(ch)
-	procsBlockedMetric.Collect(ch)
+	c.cpu.Collect(ch)
+	c.ctxt.Collect(ch)
+	c.intr.Collect(ch)
+	c.forks.Collect(ch)
+	c.btime.Collect(ch)
+	c.procsRunning.Collect(ch)
+	c.procsBlocked.Collect(ch)
 	return err
 }
diff --git a/collector/time.go b/collector/time.go
index e63efafe..83a7f23b 100644
--- a/collector/time.go
+++ b/collector/time.go
@@ -9,16 +9,9 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 )
 
-var (
-	systemTime = prometheus.NewCounter(prometheus.CounterOpts{
-		Namespace: Namespace,
-		Name:      "time",
-		Help:      "System time in seconds since epoch (1970).",
-	})
-)
-
 type timeCollector struct {
 	config Config
+	metric prometheus.Counter
 }
 
 func init() {
@@ -28,17 +21,20 @@ func init() {
 // Takes a config struct and prometheus registry and returns a new Collector exposing
 // the current system time in seconds since epoch.
 func NewTimeCollector(config Config) (Collector, error) {
-	c := timeCollector{
+	return &timeCollector{
 		config: config,
-	}
-
-	return &c, nil
+		metric: prometheus.NewCounter(prometheus.CounterOpts{
+			Namespace: Namespace,
+			Name:      "time",
+			Help:      "System time in seconds since epoch (1970).",
+		}),
+	}, nil
 }
 
 func (c *timeCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	now := time.Now()
 	glog.V(1).Infof("Set time: %f", now.Unix())
-	systemTime.Set(float64(now.Unix()))
-	systemTime.Collect(ch)
+	c.metric.Set(float64(now.Unix()))
+	c.metric.Collect(ch)
 	return err
 }