snmp: use a shared global translation cache

Prevents the same data from being looked up multiple times. Also prevents multiple simultaneous lookups.

closes #2115
closes #2104

CHANGELOG.md

@@ -1,4 +1,29 @@
+## v1.2 [unreleased]
+
+### Release Notes
+
+### Features
+
+### Bugfixes
+
 ## v1.1 [unreleased]
+- [#1949](https://github.com/influxdata/telegraf/issues/1949): Fix windows `net` plugin.
+
+## v1.1.1 [unreleased]
+## v1.1.2 [2016-12-12]
+
+### Bugfixes
+
+- [#2007](https://github.com/influxdata/telegraf/issues/2007): Make snmptranslate not required when using numeric OID.
+- [#2104](https://github.com/influxdata/telegraf/issues/2104): Add a global snmp translation cache.
+
+## v1.1.1 [2016-11-14]
+
+### Bugfixes
+
+- [#2023](https://github.com/influxdata/telegraf/issues/2023): Fix issue parsing toml durations with single quotes.
+
+## v1.1.0 [2016-11-07]
 
 ### Release Notes
 

etc/telegraf.conf

@@ -160,7 +160,7 @@
 # # Configuration for AWS CloudWatch output.
 # [[outputs.cloudwatch]]
 #   ## Amazon REGION
-#   region = 'us-east-1'
+#   region = "us-east-1"
 #
 #   ## Amazon Credentials
 #   ## Credentials are loaded in the following order
@@ -178,7 +178,7 @@
 #   #shared_credential_file = ""
 #
 #   ## Namespace for the CloudWatch MetricDatums
-#   namespace = 'InfluxData/Telegraf'
+#   namespace = "InfluxData/Telegraf"
 
 
 # # Configuration for DataDog API to send metrics to.
@@ -623,7 +623,7 @@
 # # Pull Metric Statistics from Amazon CloudWatch
 # [[inputs.cloudwatch]]
 #   ## Amazon Region
-#   region = 'us-east-1'
+#   region = "us-east-1"
 #
 #   ## Amazon Credentials
 #   ## Credentials are loaded in the following order
@@ -641,21 +641,21 @@
 #   #shared_credential_file = ""
 #
 #   ## Requested CloudWatch aggregation Period (required - must be a multiple of 60s)
-#   period = '1m'
+#   period = "5m"
 #
 #   ## Collection Delay (required - must account for metrics availability via CloudWatch API)
-#   delay = '1m'
+#   delay = "5m"
 #
 #   ## Recomended: use metric 'interval' that is a multiple of 'period' to avoid
 #   ## gaps or overlap in pulled data
-#   interval = '1m'
+#   interval = "5m"
 #
 #   ## Configure the TTL for the internal cache of metrics.
 #   ## Defaults to 1 hr if not specified
-#   #cache_ttl = '10m'
+#   #cache_ttl = "10m"
 #
 #   ## Metric Statistic Namespace (required)
-#   namespace = 'AWS/ELB'
+#   namespace = "AWS/ELB"
 #
 #   ## Maximum requests per second. Note that the global default AWS rate limit is
 #   ## 10 reqs/sec, so if you define multiple namespaces, these should add up to a
@@ -666,12 +666,12 @@
 #   ## Defaults to all Metrics in Namespace if nothing is provided
 #   ## Refreshes Namespace available metrics every 1h
 #   #[[inputs.cloudwatch.metrics]]
-#   #  names = ['Latency', 'RequestCount']
+#   #  names = ["Latency", "RequestCount"]
 #   #
 #   #  ## Dimension filters for Metric (optional)
 #   #  [[inputs.cloudwatch.metrics.dimensions]]
-#   #    name = 'LoadBalancerName'
-#   #    value = 'p-example'
+#   #    name = "LoadBalancerName"
+#   #    value = "p-example"
 
 
 # # Gather health check statuses from services registered in Consul
@@ -1979,4 +1979,3 @@
 #
 #   [inputs.webhooks.rollbar]
 #     path = "/rollbar"
-

internal/internal.go

@@ -35,8 +35,9 @@ type Duration struct {
 // UnmarshalTOML parses the duration from the TOML config file
 func (d *Duration) UnmarshalTOML(b []byte) error {
 	var err error
+	b = bytes.Trim(b, `'`)
 
-	// see if we can straight convert it
+	// see if we can directly convert it
 	d.Duration, err = time.ParseDuration(string(b))
 	if err == nil {
 		return nil

internal/internal_test.go

@@ -142,6 +142,10 @@ func TestDuration(t *testing.T) {
 	d.UnmarshalTOML([]byte(`1s`))
 	assert.Equal(t, time.Second, d.Duration)
 
+	d = Duration{}
+	d.UnmarshalTOML([]byte(`'1s'`))
+	assert.Equal(t, time.Second, d.Duration)
+
 	d = Duration{}
 	d.UnmarshalTOML([]byte(`10`))
 	assert.Equal(t, 10*time.Second, d.Duration)

plugins/inputs/cloudwatch/README.md

@@ -18,21 +18,28 @@ API endpoint. In the following order the plugin will attempt to authenticate.
 ```toml
 [[inputs.cloudwatch]]
   ## Amazon Region (required)
-  region = 'us-east-1'
+  region = "us-east-1"
 
+  # The minimum period for Cloudwatch metrics is 1 minute (60s). However not all
+  # metrics are made available to the 1 minute period. Some are collected at
+  # 3 minute and 5 minutes intervals. See https://aws.amazon.com/cloudwatch/faqs/#monitoring.
+  # Note that if a period is configured that is smaller than the minimum for a
+  # particular metric, that metric will not be returned by the Cloudwatch API
+  # and will not be collected by Telegraf.
+  #
   ## Requested CloudWatch aggregation Period (required - must be a multiple of 60s)
-  period = '1m'
+  period = "5m"
 
   ## Collection Delay (required - must account for metrics availability via CloudWatch API)
-  delay = '1m'
+  delay = "5m"
 
   ## Override global run interval (optional - defaults to global interval)
   ## Recomended: use metric 'interval' that is a multiple of 'period' to avoid
   ## gaps or overlap in pulled data
-  interval = '1m'
+  interval = "5m"
 
   ## Metric Statistic Namespace (required)
-  namespace = 'AWS/ELB'
+  namespace = "AWS/ELB"
 
   ## Maximum requests per second. Note that the global default AWS rate limit is
   ## 10 reqs/sec, so if you define multiple namespaces, these should add up to a
@@ -43,16 +50,16 @@ API endpoint. In the following order the plugin will attempt to authenticate.
   ## Defaults to all Metrics in Namespace if nothing is provided
   ## Refreshes Namespace available metrics every 1h
   [[inputs.cloudwatch.metrics]]
-    names = ['Latency', 'RequestCount']
+    names = ["Latency", "RequestCount"]
 
     ## Dimension filters for Metric (optional)
     [[inputs.cloudwatch.metrics.dimensions]]
-      name = 'LoadBalancerName'
-      value = 'p-example'
+      name = "LoadBalancerName"
+      value = "p-example"
 
     [[inputs.cloudwatch.metrics.dimensions]]
-      name = 'AvailabilityZone'
-      value = '*'
+      name = "AvailabilityZone"
+      value = "*"
 ```
 #### Requirements and Terminology
 
@@ -71,16 +78,16 @@ wildcard dimension is ignored.
 Example:
 ```
 [[inputs.cloudwatch.metrics]]
-  names = ['Latency']
+  names = ["Latency"]
 
   ## Dimension filters for Metric (optional)
   [[inputs.cloudwatch.metrics.dimensions]]
-    name = 'LoadBalancerName'
-    value = 'p-example'
+    name = "LoadBalancerName"
+    value = "p-example"
 
   [[inputs.cloudwatch.metrics.dimensions]]
-    name = 'AvailabilityZone'
-    value = '*'
+    name = "AvailabilityZone"
+    value = "*"
 ```
 
 If the following ELBs are available:

plugins/inputs/cloudwatch/cloudwatch.go

@@ -63,7 +63,7 @@ type (
 func (c *CloudWatch) SampleConfig() string {
 	return `
   ## Amazon Region
-  region = 'us-east-1'
+  region = "us-east-1"
 
   ## Amazon Credentials
   ## Credentials are loaded in the following order
@@ -80,22 +80,29 @@ func (c *CloudWatch) SampleConfig() string {
   #profile = ""
   #shared_credential_file = ""
 
+  # The minimum period for Cloudwatch metrics is 1 minute (60s). However not all
+  # metrics are made available to the 1 minute period. Some are collected at
+  # 3 minute and 5 minutes intervals. See https://aws.amazon.com/cloudwatch/faqs/#monitoring.
+  # Note that if a period is configured that is smaller than the minimum for a
+  # particular metric, that metric will not be returned by the Cloudwatch API
+  # and will not be collected by Telegraf.
+  #
   ## Requested CloudWatch aggregation Period (required - must be a multiple of 60s)
-  period = '1m'
+  period = "5m"
 
   ## Collection Delay (required - must account for metrics availability via CloudWatch API)
-  delay = '1m'
+  delay = "5m"
 
   ## Recomended: use metric 'interval' that is a multiple of 'period' to avoid
   ## gaps or overlap in pulled data
-  interval = '1m'
+  interval = "5m"
 
   ## Configure the TTL for the internal cache of metrics.
   ## Defaults to 1 hr if not specified
-  #cache_ttl = '10m'
+  #cache_ttl = "10m"
 
   ## Metric Statistic Namespace (required)
-  namespace = 'AWS/ELB'
+  namespace = "AWS/ELB"
 
   ## Maximum requests per second. Note that the global default AWS rate limit is
   ## 10 reqs/sec, so if you define multiple namespaces, these should add up to a
@@ -106,12 +113,12 @@ func (c *CloudWatch) SampleConfig() string {
   ## Defaults to all Metrics in Namespace if nothing is provided
   ## Refreshes Namespace available metrics every 1h
   #[[inputs.cloudwatch.metrics]]
-  #  names = ['Latency', 'RequestCount']
+  #  names = ["Latency", "RequestCount"]
   #
   #  ## Dimension filters for Metric (optional)
   #  [[inputs.cloudwatch.metrics.dimensions]]
-  #    name = 'LoadBalancerName'
-  #    value = 'p-example'
+  #    name = "LoadBalancerName"
+  #    value = "p-example"
 `
 }
 
@@ -133,7 +140,6 @@ func (c *CloudWatch) Gather(acc telegraf.Accumulator) error {
 			if !hasWilcard(m.Dimensions) {
 				dimensions := make([]*cloudwatch.Dimension, len(m.Dimensions))
 				for k, d := range m.Dimensions {
-					fmt.Printf("Dimension [%s]:[%s]\n", d.Name, d.Value)
 					dimensions[k] = &cloudwatch.Dimension{
 						Name:  aws.String(d.Name),
 						Value: aws.String(d.Value),
@@ -229,13 +235,12 @@ func (c *CloudWatch) initializeCloudWatch() error {
 /*
  * Fetch available metrics for given CloudWatch Namespace
  */
-func (c *CloudWatch) fetchNamespaceMetrics() (metrics []*cloudwatch.Metric, err error) {
+func (c *CloudWatch) fetchNamespaceMetrics() ([]*cloudwatch.Metric, error) {
 	if c.metricCache != nil && c.metricCache.IsValid() {
-		metrics = c.metricCache.Metrics
-		return
+		return c.metricCache.Metrics, nil
 	}
 
-	metrics = []*cloudwatch.Metric{}
+	metrics := []*cloudwatch.Metric{}
 
 	var token *string
 	for more := true; more; {
@@ -263,7 +268,7 @@ func (c *CloudWatch) fetchNamespaceMetrics() (metrics []*cloudwatch.Metric, err
 		TTL:     c.CacheTTL.Duration,
 	}
 
-	return
+	return metrics, nil
 }
 
 /*

plugins/inputs/snmp/snmp.go

@@ -8,6 +8,7 @@ import (
 	"os/exec"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/influxdata/telegraf"
@@ -199,65 +200,22 @@ func (t *Table) init() error {
 	return nil
 }
 
-// init() populates Fields if a table OID is provided.
+// initBuild initializes the table if it has an OID configured. If so, the
+// net-snmp tools will be used to look up the OID and auto-populate the table's
+// fields.
 func (t *Table) initBuild() error {
 	if t.Oid == "" {
 		return nil
 	}
 
-	mibName, _, oidText, _, err := snmpTranslate(t.Oid)
+	_, _, oidText, fields, err := snmpTable(t.Oid)
 	if err != nil {
-		return Errorf(err, "translating %s", t.Oid)
+		return Errorf(err, "initializing table %s", t.Oid)
 	}
 	if t.Name == "" {
 		t.Name = oidText
 	}
-	mibPrefix := mibName + "::"
-	oidFullName := mibPrefix + oidText
-
-	// first attempt to get the table's tags
-	tagOids := map[string]struct{}{}
-	// We have to guess that the "entry" oid is `t.Oid+".1"`. snmptable and snmptranslate don't seem to have a way to provide the info.
-	if out, err := execCmd("snmptranslate", "-Td", oidFullName+".1"); err == nil {
-		lines := bytes.Split(out, []byte{'\n'})
-		for _, line := range lines {
-			if !bytes.HasPrefix(line, []byte("  INDEX")) {
-				continue
-			}
-
-			i := bytes.Index(line, []byte("{ "))
-			if i == -1 { // parse error
-				continue
-			}
-			line = line[i+2:]
-			i = bytes.Index(line, []byte(" }"))
-			if i == -1 { // parse error
-				continue
-			}
-			line = line[:i]
-			for _, col := range bytes.Split(line, []byte(", ")) {
-				tagOids[mibPrefix+string(col)] = struct{}{}
-			}
-		}
-	}
-
-	// this won't actually try to run a query. The `-Ch` will just cause it to dump headers.
-	out, err := execCmd("snmptable", "-Ch", "-Cl", "-c", "public", "127.0.0.1", oidFullName)
-	if err != nil {
-		return Errorf(err, "getting table columns for %s", t.Oid)
-	}
-	cols := bytes.SplitN(out, []byte{'\n'}, 2)[0]
-	if len(cols) == 0 {
-		return fmt.Errorf("unable to get columns for table %s", t.Oid)
-	}
-	for _, col := range bytes.Split(cols, []byte{' '}) {
-		if len(col) == 0 {
-			continue
-		}
-		col := string(col)
-		_, isTag := tagOids[mibPrefix+col]
-		t.Fields = append(t.Fields, Field{Name: col, Oid: mibPrefix + col, IsTag: isTag})
-	}
+	t.Fields = append(t.Fields, fields...)
 
 	return nil
 }
@@ -841,13 +799,141 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
 	return nil, fmt.Errorf("invalid conversion type '%s'", conv)
 }
 
+type snmpTableCache struct {
+	mibName string
+	oidNum  string
+	oidText string
+	fields  []Field
+	err     error
+}
+
+var snmpTableCaches map[string]snmpTableCache
+var snmpTableCachesLock sync.Mutex
+
+// snmpTable resolves the given OID as a table, providing information about the
+// table and fields within.
+func snmpTable(oid string) (mibName string, oidNum string, oidText string, fields []Field, err error) {
+	snmpTableCachesLock.Lock()
+	if snmpTableCaches == nil {
+		snmpTableCaches = map[string]snmpTableCache{}
+	}
+
+	var stc snmpTableCache
+	var ok bool
+	if stc, ok = snmpTableCaches[oid]; !ok {
+		stc.mibName, stc.oidNum, stc.oidText, stc.fields, stc.err = snmpTableCall(oid)
+		snmpTableCaches[oid] = stc
+	}
+
+	snmpTableCachesLock.Unlock()
+	return stc.mibName, stc.oidNum, stc.oidText, stc.fields, stc.err
+}
+
+func snmpTableCall(oid string) (mibName string, oidNum string, oidText string, fields []Field, err error) {
+	mibName, oidNum, oidText, _, err = snmpTranslate(oid)
+	if err != nil {
+		return "", "", "", nil, Errorf(err, "translating")
+	}
+
+	mibPrefix := mibName + "::"
+	oidFullName := mibPrefix + oidText
+
+	// first attempt to get the table's tags
+	tagOids := map[string]struct{}{}
+	// We have to guess that the "entry" oid is `oid+".1"`. snmptable and snmptranslate don't seem to have a way to provide the info.
+	if out, err := execCmd("snmptranslate", "-Td", oidFullName+".1"); err == nil {
+		lines := bytes.Split(out, []byte{'\n'})
+		for _, line := range lines {
+			if !bytes.HasPrefix(line, []byte("  INDEX")) {
+				continue
+			}
+
+			i := bytes.Index(line, []byte("{ "))
+			if i == -1 { // parse error
+				continue
+			}
+			line = line[i+2:]
+			i = bytes.Index(line, []byte(" }"))
+			if i == -1 { // parse error
+				continue
+			}
+			line = line[:i]
+			for _, col := range bytes.Split(line, []byte(", ")) {
+				tagOids[mibPrefix+string(col)] = struct{}{}
+			}
+		}
+	}
+
+	// this won't actually try to run a query. The `-Ch` will just cause it to dump headers.
+	out, err := execCmd("snmptable", "-Ch", "-Cl", "-c", "public", "127.0.0.1", oidFullName)
+	if err != nil {
+		return "", "", "", nil, Errorf(err, "getting table columns")
+	}
+	cols := bytes.SplitN(out, []byte{'\n'}, 2)[0]
+	if len(cols) == 0 {
+		return "", "", "", nil, fmt.Errorf("could not find any columns in table")
+	}
+	for _, col := range bytes.Split(cols, []byte{' '}) {
+		if len(col) == 0 {
+			continue
+		}
+		col := string(col)
+		_, isTag := tagOids[mibPrefix+col]
+		fields = append(fields, Field{Name: col, Oid: mibPrefix + col, IsTag: isTag})
+	}
+
+	return mibName, oidNum, oidText, fields, err
+}
+
+type snmpTranslateCache struct {
+	mibName    string
+	oidNum     string
+	oidText    string
+	conversion string
+	err        error
+}
+
+var snmpTranslateCachesLock sync.Mutex
+var snmpTranslateCaches map[string]snmpTranslateCache
+
 // snmpTranslate resolves the given OID.
 func snmpTranslate(oid string) (mibName string, oidNum string, oidText string, conversion string, err error) {
+	snmpTranslateCachesLock.Lock()
+	if snmpTranslateCaches == nil {
+		snmpTranslateCaches = map[string]snmpTranslateCache{}
+	}
+
+	var stc snmpTranslateCache
+	var ok bool
+	if stc, ok = snmpTranslateCaches[oid]; !ok {
+		// This will result in only one call to snmptranslate running at a time.
+		// We could speed it up by putting a lock in snmpTranslateCache and then
+		// returning it immediately, and multiple callers would then release the
+		// snmpTranslateCachesLock and instead wait on the individual
+		// snmpTranlsation.Lock to release. But I don't know that the extra complexity
+		// is worth it. Especially when it would slam the system pretty hard if lots
+		// of lookups are being perfomed.
+
+		stc.mibName, stc.oidNum, stc.oidText, stc.conversion, stc.err = snmpTranslateCall(oid)
+		snmpTranslateCaches[oid] = stc
+	}
+
+	snmpTranslateCachesLock.Unlock()
+
+	return stc.mibName, stc.oidNum, stc.oidText, stc.conversion, stc.err
+}
+
+func snmpTranslateCall(oid string) (mibName string, oidNum string, oidText string, conversion string, err error) {
 	var out []byte
 	if strings.ContainsAny(oid, ":abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ") {
 		out, err = execCmd("snmptranslate", "-Td", "-Ob", oid)
 	} else {
 		out, err = execCmd("snmptranslate", "-Td", "-Ob", "-m", "all", oid)
+		if err, ok := err.(*exec.Error); ok && err.Err == exec.ErrNotFound {
+			// Silently discard error if snmptranslate not found and we have a numeric OID.
+			// Meaning we can get by without the lookup.
+			return "", oid, oid, "", nil
+		}
 	}
 	if err != nil {
 		return "", "", "", "", err

plugins/inputs/snmp/snmp_test.go

@@ -4,6 +4,7 @@ package snmp
 import (
 	"fmt"
 	"net"
+	"os/exec"
 	"sync"
 	"testing"
 	"time"
@@ -198,6 +199,56 @@ func TestSnmpInit(t *testing.T) {
 	}, s.Fields[0])
 }
 
+func TestSnmpInit_noTranslate(t *testing.T) {
+	// override execCommand so it returns exec.ErrNotFound
+	defer func(ec func(string, ...string) *exec.Cmd) { execCommand = ec }(execCommand)
+	execCommand = func(_ string, _ ...string) *exec.Cmd {
+		return exec.Command("snmptranslateExecErrNotFound")
+	}
+
+	s := &Snmp{
+		Fields: []Field{
+			{Oid: ".1.1.1.1", Name: "one", IsTag: true},
+			{Oid: ".1.1.1.2", Name: "two"},
+			{Oid: ".1.1.1.3"},
+		},
+		Tables: []Table{
+			{Fields: []Field{
+				{Oid: ".1.1.1.4", Name: "four", IsTag: true},
+				{Oid: ".1.1.1.5", Name: "five"},
+				{Oid: ".1.1.1.6"},
+			}},
+		},
+	}
+
+	err := s.init()
+	require.NoError(t, err)
+
+	assert.Equal(t, ".1.1.1.1", s.Fields[0].Oid)
+	assert.Equal(t, "one", s.Fields[0].Name)
+	assert.Equal(t, true, s.Fields[0].IsTag)
+
+	assert.Equal(t, ".1.1.1.2", s.Fields[1].Oid)
+	assert.Equal(t, "two", s.Fields[1].Name)
+	assert.Equal(t, false, s.Fields[1].IsTag)
+
+	assert.Equal(t, ".1.1.1.3", s.Fields[2].Oid)
+	assert.Equal(t, ".1.1.1.3", s.Fields[2].Name)
+	assert.Equal(t, false, s.Fields[2].IsTag)
+
+	assert.Equal(t, ".1.1.1.4", s.Tables[0].Fields[0].Oid)
+	assert.Equal(t, "four", s.Tables[0].Fields[0].Name)
+	assert.Equal(t, true, s.Tables[0].Fields[0].IsTag)
+
+	assert.Equal(t, ".1.1.1.5", s.Tables[0].Fields[1].Oid)
+	assert.Equal(t, "five", s.Tables[0].Fields[1].Name)
+	assert.Equal(t, false, s.Tables[0].Fields[1].IsTag)
+
+	assert.Equal(t, ".1.1.1.6", s.Tables[0].Fields[2].Oid)
+	assert.Equal(t, ".1.1.1.6", s.Tables[0].Fields[2].Name)
+	assert.Equal(t, false, s.Tables[0].Fields[2].IsTag)
+}
+
 func TestGetSNMPConnection_v2(t *testing.T) {
 	s := &Snmp{
 		Timeout:   internal.Duration{Duration: 3 * time.Second},
@@ -597,6 +648,71 @@ func TestFieldConvert(t *testing.T) {
 	}
 }
 
+func TestSnmpTranslateCache_miss(t *testing.T) {
+	snmpTranslateCaches = nil
+	oid := "IF-MIB::ifPhysAddress.1"
+	mibName, oidNum, oidText, conversion, err := snmpTranslate(oid)
+	assert.Len(t, snmpTranslateCaches, 1)
+	stc := snmpTranslateCaches[oid]
+	require.NotNil(t, stc)
+	assert.Equal(t, mibName, stc.mibName)
+	assert.Equal(t, oidNum, stc.oidNum)
+	assert.Equal(t, oidText, stc.oidText)
+	assert.Equal(t, conversion, stc.conversion)
+	assert.Equal(t, err, stc.err)
+}
+
+func TestSnmpTranslateCache_hit(t *testing.T) {
+	snmpTranslateCaches = map[string]snmpTranslateCache{
+		"foo": snmpTranslateCache{
+			mibName:    "a",
+			oidNum:     "b",
+			oidText:    "c",
+			conversion: "d",
+			err:        fmt.Errorf("e"),
+		},
+	}
+	mibName, oidNum, oidText, conversion, err := snmpTranslate("foo")
+	assert.Equal(t, "a", mibName)
+	assert.Equal(t, "b", oidNum)
+	assert.Equal(t, "c", oidText)
+	assert.Equal(t, "d", conversion)
+	assert.Equal(t, fmt.Errorf("e"), err)
+	snmpTranslateCaches = nil
+}
+
+func TestSnmpTableCache_miss(t *testing.T) {
+	snmpTableCaches = nil
+	oid := ".1.0.0.0"
+	mibName, oidNum, oidText, fields, err := snmpTable(oid)
+	assert.Len(t, snmpTableCaches, 1)
+	stc := snmpTableCaches[oid]
+	require.NotNil(t, stc)
+	assert.Equal(t, mibName, stc.mibName)
+	assert.Equal(t, oidNum, stc.oidNum)
+	assert.Equal(t, oidText, stc.oidText)
+	assert.Equal(t, fields, stc.fields)
+	assert.Equal(t, err, stc.err)
+}
+
+func TestSnmpTableCache_hit(t *testing.T) {
+	snmpTableCaches = map[string]snmpTableCache{
+		"foo": snmpTableCache{
+			mibName: "a",
+			oidNum:  "b",
+			oidText: "c",
+			fields:  []Field{{Name: "d"}},
+			err:     fmt.Errorf("e"),
+		},
+	}
+	mibName, oidNum, oidText, fields, err := snmpTable("foo")
+	assert.Equal(t, "a", mibName)
+	assert.Equal(t, "b", oidNum)
+	assert.Equal(t, "c", oidText)
+	assert.Equal(t, []Field{{Name: "d"}}, fields)
+	assert.Equal(t, fmt.Errorf("e"), err)
+}
+
 func TestError(t *testing.T) {
 	e := fmt.Errorf("nested error")
 	err := Errorf(e, "top error %d", 123)

plugins/outputs/cloudwatch/cloudwatch.go

@@ -30,7 +30,7 @@ type CloudWatch struct {
 
 var sampleConfig = `
   ## Amazon REGION
-  region = 'us-east-1'
+  region = "us-east-1"
 
   ## Amazon Credentials
   ## Credentials are loaded in the following order
@@ -48,7 +48,7 @@ var sampleConfig = `
   #shared_credential_file = ""
 
   ## Namespace for the CloudWatch MetricDatums
-  namespace = 'InfluxData/Telegraf'
+  namespace = "InfluxData/Telegraf"
 `
 
 func (c *CloudWatch) SampleConfig() string {

scripts/circle-test.sh

@@ -82,6 +82,6 @@ if [ $? -eq 0 ]; then
     unset GOGC
     tag=$(git describe --exact-match HEAD)
     echo $tag
-    exit_if_fail ./scripts/build.py --release --package --version=$tag --platform=all --arch=all --upload --bucket=dl.influxdata.com/telegraf/releases
+    exit_if_fail ./scripts/build.py --release --package --platform=all --arch=all --upload --bucket=dl.influxdata.com/telegraf/releases
     mv build $CIRCLE_ARTIFACTS
 fi