Merge pull request #8 from app-sre/rds_conn

Add RDS max_connections metric

go.mod

@@ -3,7 +3,7 @@ module github.com/app-sre/aws-resource-exporter
 go 1.12
 
 require (
-	github.com/aws/aws-sdk-go v1.15.77
+	github.com/aws/aws-sdk-go v1.25.9
 	github.com/prometheus/client_golang v0.9.3
 	github.com/prometheus/common v0.4.1
 	github.com/prometheus/procfs v0.0.2 // indirect

go.sum

@@ -3,8 +3,8 @@ github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc h1:cAKDfWh5Vpd
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf h1:qet1QNfXsQxTZqLG4oE62mJzwPIB8+Tee4RNCL9ulrY=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
-github.com/aws/aws-sdk-go v1.15.77 h1:qlut2MDI5mRKllPC6grO5n9M8UhPQg1TIA9cYAkC/gc=
-github.com/aws/aws-sdk-go v1.15.77/go.mod h1:E3/ieXAlvM0XWO57iftYVDLLvQ824smPP3ATZkfNZeM=
+github.com/aws/aws-sdk-go v1.25.9 h1:WtVzerf5wSgPwlTTwl+ktCq/0GCS5MI9ZlLIcjsTr+Q=
+github.com/aws/aws-sdk-go v1.25.9/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 h1:xJ4a3vCFaGF/jqvzLMYoU8P317H5OQ+Via4RmuPwCS0=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0 h1:HWo1m869IqiPhD389kmkxeTalrjNbbJTC8LXupb+sl0=
@@ -22,13 +22,14 @@ github.com/go-logfmt/logfmt v0.4.0 h1:MP4Eh7ZCb31lleYCFuwm0oe4/YGak+5l1vA2NOE80n
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
 github.com/go-stack/stack v1.8.0 h1:5SgMzNM5HxrEjV0ww2lTmX6E2Izsfxas4+YHWRs3Lsk=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/gogo/protobuf v1.1.1 h1:72R+M5VuhED/KujmZVcIquuo8mBgX4oVda//DQb3PXo=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
-github.com/jmespath/go-jmespath v0.0.0-20160202185014-0b12d6b521d8 h1:12VvqtR6Aowv3l/EQUlocDHW2Cp4G9WJVH7uyH8QFJE=
-github.com/jmespath/go-jmespath v0.0.0-20160202185014-0b12d6b521d8/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af h1:pmfjZENx5imkbgOkpRUYLnmbU7UEFbjtDA2hxJ1ichM=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=

rds.go

@@ -1,56 +1,98 @@
 package main
 
 import (
+	"sync"
+
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/rds"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
 )
 
+// DBMaxConnections is a hardcoded map of instance types and DB Parameter Group names
+// This is a dump workaround created because by default the DB Parameter Group `max_connections` is a function
+// that is hard to parse and process in code and it contains a variable whose value is unknown to us (DBInstanceClassMemory)
+// AWS has no means to return the actual `max_connections` value.
+var DBMaxConnections = map[string]map[string]int64{
+	"db.t2.small": map[string]int64{
+		"default.mysql5.7": 150,
+	},
+	"db.m5.2xlarge": map[string]int64{
+		"default.postgres10": 3429,
+	},
+	"db.m5.large": map[string]int64{
+		"default.postgres10": 823,
+	},
+}
+
+// RDSExporter defines an instance of the RDS Exporter
 type RDSExporter struct {
-	sess             *session.Session
-	AllocatedStorage *prometheus.Desc
-	DBInstanceClass  *prometheus.Desc
-	DBInstanceStatus *prometheus.Desc
-	EngineVersion    *prometheus.Desc
+	sess                        *session.Session
+	AllocatedStorage            *prometheus.Desc
+	DBInstanceClass             *prometheus.Desc
+	DBInstanceStatus            *prometheus.Desc
+	EngineVersion               *prometheus.Desc
+	MaxConnections              *prometheus.Desc
+	MaxConnectionsMappingErrors *prometheus.Desc
+
+	MaxConnectionsMappingErrorsValue float64
+
+	mutex *sync.Mutex
 }
 
+// NewRDSExporter creates a new RDSExporter instance
 func NewRDSExporter(sess *session.Session) *RDSExporter {
+	log.Info("[RDS] Initializing RDS exporter")
 	return &RDSExporter{
-		sess: sess,
+		sess:  sess,
+		mutex: &sync.Mutex{},
 		AllocatedStorage: prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "", "allocatedstorage"),
+			prometheus.BuildFQName(namespace, "", "rds_allocatedstorage"),
 			"The amount of allocated storage in bytes.",
 			[]string{"aws_region", "dbinstance_identifier"},
 			nil,
 		),
 		DBInstanceClass: prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "", "dbinstanceclass"),
+			prometheus.BuildFQName(namespace, "", "rds_dbinstanceclass"),
 			"The DB instance class (type).",
 			[]string{"aws_region", "dbinstance_identifier", "instance_class"},
 			nil,
 		),
 		DBInstanceStatus: prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "", "dbinstancestatus"),
+			prometheus.BuildFQName(namespace, "", "rds_dbinstancestatus"),
 			"The instance status.",
 			[]string{"aws_region", "dbinstance_identifier", "instance_status"},
 			nil,
 		),
 		EngineVersion: prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "", "engineversion"),
+			prometheus.BuildFQName(namespace, "", "rds_engineversion"),
 			"The DB engine type and version.",
 			[]string{"aws_region", "dbinstance_identifier", "engine", "engine_version"},
 			nil,
 		),
+		MaxConnections: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "", "rds_maxconnections"),
+			"The DB's max_connections value",
+			[]string{"aws_region", "dbinstance_identifier"},
+			nil,
+		),
+		MaxConnectionsMappingErrors: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "", "rds_maxconnections_errors"),
+			"Indicates no mapping found for instance/parameter group.",
+			[]string{},
+			nil,
+		),
 	}
 }
 
+// Describe is used by the Prometheus client to return a description of the metrics
 func (e *RDSExporter) Describe(ch chan<- *prometheus.Desc) {
 	ch <- e.AllocatedStorage
 	ch <- e.DBInstanceStatus
 	ch <- e.EngineVersion
 }
 
+// Collect is used by the Prometheus client to collect and return the metrics values
 func (e *RDSExporter) Collect(ch chan<- prometheus.Metric) {
 	svc := rds.New(e.sess)
 	input := &rds.DescribeDBInstancesInput{}
@@ -73,41 +115,35 @@ func (e *RDSExporter) Collect(ch chan<- prometheus.Metric) {
 		}
 	}
 
-	parameterGroups := make(map[string][]*rds.Parameter)
 	for _, instance := range instances {
-		for _, dbpg := range instance.DBParameterGroups {
-			if *dbpg.ParameterApplyStatus == "in-sync" {
-				if _, ok := parameterGroups[*dbpg.DBParameterGroupName]; ok {
-					log.Debugln("ParameterGroup", *dbpg.DBParameterGroupName, "exists in cache.")
-					continue
-				}
-
-				log.Debugln("Fetching parameters for group", *dbpg.DBParameterGroupName)
-				input := &rds.DescribeDBParametersInput{
-					DBParameterGroupName: dbpg.DBParameterGroupName,
-				}
-				var parameters []*rds.Parameter
-				for {
-					exporterMetrics.IncrementRequests()
-					result, err := svc.DescribeDBParameters(input)
-					if err != nil {
-						log.Errorf("[RDS] Call to DescribeDBInstances failed in region %s: %s", *e.sess.Config.Region, err)
-						exporterMetrics.IncrementErrors()
-						return
-					}
-					parameters = append(parameters, result.Parameters...)
-					input.Marker = result.Marker
-					if result.Marker == nil {
-						break
-					}
-				}
-				parameterGroups[*dbpg.DBParameterGroupName] = parameters
+		var maxConnections int64
+		if val, ok := DBMaxConnections[*instance.DBInstanceClass]; ok {
+			if val, ok := val[*instance.DBParameterGroups[0].DBParameterGroupName]; ok {
+				log.Debugf("[RDS] Found mapping for instance type %s group %s value %d",
+					*instance.DBInstanceClass,
+					*instance.DBParameterGroups[0].DBParameterGroupName,
+					val)
+				maxConnections = val
+			} else {
+				log.Errorf("[RDS] No DB max_connections mapping exists for instance type %s parameter group %s",
+					*instance.DBInstanceClass,
+					*instance.DBParameterGroups[0].DBParameterGroupName)
+				e.mutex.Lock()
+				e.MaxConnectionsMappingErrorsValue++
+				e.mutex.Unlock()
 			}
+		} else {
+			log.Errorf("[RDS] No DB max_connections mapping exists for instance type %s",
+				*instance.DBInstanceClass)
+			e.mutex.Lock()
+			e.MaxConnectionsMappingErrorsValue++
+			e.mutex.Unlock()
 		}
-
+		ch <- prometheus.MustNewConstMetric(e.MaxConnections, prometheus.GaugeValue, float64(maxConnections), *e.sess.Config.Region, *instance.DBInstanceIdentifier)
 		ch <- prometheus.MustNewConstMetric(e.AllocatedStorage, prometheus.GaugeValue, float64(*instance.AllocatedStorage*1024*1024*1024), *e.sess.Config.Region, *instance.DBInstanceIdentifier)
 		ch <- prometheus.MustNewConstMetric(e.DBInstanceStatus, prometheus.GaugeValue, 1, *e.sess.Config.Region, *instance.DBInstanceIdentifier, *instance.DBInstanceStatus)
 		ch <- prometheus.MustNewConstMetric(e.EngineVersion, prometheus.GaugeValue, 1, *e.sess.Config.Region, *instance.DBInstanceIdentifier, *instance.Engine, *instance.EngineVersion)
 		ch <- prometheus.MustNewConstMetric(e.DBInstanceClass, prometheus.GaugeValue, 1, *e.sess.Config.Region, *instance.DBInstanceIdentifier, *instance.DBInstanceClass)
 	}
+	ch <- prometheus.MustNewConstMetric(e.MaxConnectionsMappingErrors, prometheus.CounterValue, e.MaxConnectionsMappingErrorsValue)
 }