Merge branch 'master' into master

Author: wrouesnel

Dockerfile

@@ -2,6 +2,6 @@ FROM scratch
 
 COPY postgres_exporter /postgres_exporter
 
-EXPOSE 9113
+EXPOSE 9187
 
 ENTRYPOINT [ "/postgres_exporter" ]

Makefile

@@ -21,7 +21,7 @@ vet:
 	go vet .
 
 test:
-	go test -v .
+	go test -v -cover .
 
 test-integration: postgres_exporter postgres_exporter_integration_test
 	tests/test-smoke ./postgres_exporter ./postgres_exporter_integration_test

postgres_exporter.go

@@ -2,25 +2,24 @@ package main
 
 import (
 	"database/sql"
+	"errors"
 	"flag"
 	"fmt"
 	"io/ioutil"
 	"math"
 	"net/http"
 	"os"
-	"strconv"
-	"time"
 	"regexp"
-	"errors"
+	"strconv"
 	"sync"
+	"time"
 
 	"gopkg.in/yaml.v2"
 
+	"github.com/blang/semver"
 	_ "github.com/lib/pq"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
-	"github.com/blang/semver"
-
 )
 
 var Version string = "0.0.1"
@@ -116,10 +115,10 @@ func parseVersion(versionString string) (semver.Version, error) {
 
 // User-friendly representation of a prometheus descriptor map
 type ColumnMapping struct {
-	usage       ColumnUsage			`yaml:"usage"`
-	description string				`yaml:"description"`
-	mapping     map[string]float64 	`yaml:"metric_mapping"` // Optional column mapping for MAPPEDMETRIC
-	supportedVersions semver.Range	`yaml:"pg_version"`	// Semantic version ranges which are supported. Unsupported columns are not queried (internally converted to DISCARD).
+	usage             ColumnUsage        `yaml:"usage"`
+	description       string             `yaml:"description"`
+	mapping           map[string]float64 `yaml:"metric_mapping"` // Optional column mapping for MAPPEDMETRIC
+	supportedVersions semver.Range       `yaml:"pg_version"`     // Semantic version ranges which are supported. Unsupported columns are not queried (internally converted to DISCARD).
 }
 
 func (this *ColumnMapping) UnmarshalYAML(unmarshal func(interface{}) error) error {
@@ -232,7 +231,7 @@ var metricMaps = map[string]map[string]ColumnMapping{
 		"count":   {GAUGE, "Number of locks", nil, nil},
 	},
 	"pg_stat_replication": map[string]ColumnMapping{
-		"procpid":			{DISCARD, "Process ID of a WAL sender process", nil, semver.MustParseRange("<9.2.0")},
+		"procpid":          {DISCARD, "Process ID of a WAL sender process", nil, semver.MustParseRange("<9.2.0")},
 		"pid":              {DISCARD, "Process ID of a WAL sender process", nil, semver.MustParseRange(">=9.2.0")},
 		"usesysid":         {DISCARD, "OID of the user logged into this WAL sender process", nil, nil},
 		"usename":          {DISCARD, "Name of the user logged into this WAL sender process", nil, nil},
@@ -277,7 +276,7 @@ var metricMaps = map[string]map[string]ColumnMapping{
 // the semver matching we do for columns.
 type OverrideQuery struct {
 	versionRange semver.Range
-	query string
+	query        string
 }
 
 // Overriding queries for namespaces above.
@@ -359,7 +358,6 @@ var queryOverrides = map[string][]OverrideQuery{
 		},
 		// No query is applicable for 9.1 that gives any sensible data.
 	},
-
 }
 
 // Convert the query override file to the version-specific query override file
@@ -510,7 +508,10 @@ func makeDescMap(pgVersion semver.Version, metricMaps map[string]map[string]Colu
 			// Check column version compatibility for the current map
 			// Force to discard if not compatible.
 			if columnMapping.supportedVersions != nil {
-				if columnMapping.supportedVersions(pgVersion) {
+				if !columnMapping.supportedVersions(pgVersion) {
+					// It's very useful to be able to see what columns are being
+					// rejected.
+					log.Debugln(columnName, "is being forced to discard due to version incompatibility.")
 					thisMap[columnName] = MetricMap{
 						discard: true,
 						conversion: func(in interface{}) (float64, bool) {
@@ -684,26 +685,26 @@ func dbToString(t interface{}) (string, bool) {
 // Exporter collects Postgres metrics. It implements prometheus.Collector.
 type Exporter struct {
 	dsn             string
-	userQueriesPath	string
+	userQueriesPath string
 	duration, error prometheus.Gauge
 	totalScrapes    prometheus.Counter
 
 	// Last version used to calculate metric map. If mismatch on scrape,
 	// then maps are recalculated.
-	lastMapVersion	semver.Version
+	lastMapVersion semver.Version
 	// Currently active variable map
-	variableMap     map[string]MetricMapNamespace
+	variableMap map[string]MetricMapNamespace
 	// Currently active metric map
-	metricMap       map[string]MetricMapNamespace
+	metricMap map[string]MetricMapNamespace
 	// Currently active query overrides
-	queryOverrides 	map[string]string
-	mappingMtx sync.RWMutex
+	queryOverrides map[string]string
+	mappingMtx     sync.RWMutex
 }
 
 // NewExporter returns a new PostgreSQL exporter for the provided DSN.
 func NewExporter(dsn string, userQueriesPath string) *Exporter {
 	return &Exporter{
-		dsn: dsn,
+		dsn:             dsn,
 		userQueriesPath: userQueriesPath,
 		duration: prometheus.NewGauge(prometheus.GaugeOpts{
 			Namespace: namespace,
@@ -723,8 +724,8 @@ func NewExporter(dsn string, userQueriesPath string) *Exporter {
 			Name:      "last_scrape_error",
 			Help:      "Whether the last scrape of metrics from PostgreSQL resulted in an error (1 for error, 0 for success).",
 		}),
-		variableMap: nil,
-		metricMap:   nil,
+		variableMap:    nil,
+		metricMap:      nil,
 		queryOverrides: nil,
 	}
 }
@@ -949,7 +950,7 @@ func (e *Exporter) checkMapVersions(ch chan<- prometheus.Metric, db *sql.DB) err
 		e.lastMapVersion = semanticVersion
 
 		if e.userQueriesPath != "" {
-			if err := addQueries(e.userQueriesPath, semanticVersion, e.metricMap, e.queryOverrides) ; err != nil {
+			if err := addQueries(e.userQueriesPath, semanticVersion, e.metricMap, e.queryOverrides); err != nil {
 				log.Errorln("Failed to reload user queries:", e.userQueriesPath, err)
 			}
 		}

postgres_exporter_test.go

@@ -0,0 +1,87 @@
+// +build !integration
+
+package main
+
+import (
+	"testing"
+	. "gopkg.in/check.v1"
+
+	"github.com/blang/semver"
+)
+
+// Hook up gocheck into the "go test" runner.
+func Test(t *testing.T) { TestingT(t) }
+
+type FunctionalSuite struct{
+	e *Exporter
+}
+
+var _ = Suite(&FunctionalSuite{})
+
+func (s *FunctionalSuite) SetUpSuite(c *C) {
+
+}
+
+func (s *FunctionalSuite) TestSemanticVersionColumnDiscard(c *C) {
+	testMetricMap := map[string]map[string]ColumnMapping{
+		"test_namespace" : map[string]ColumnMapping{
+			"metric_which_stays" : {COUNTER, "This metric should not be eliminated", nil, nil},
+			"metric_which_discards" : {COUNTER, "This metric should be forced to DISCARD", nil, nil},
+		},
+	}
+
+	{
+		// No metrics should be eliminated
+		resultMap := makeDescMap(semver.MustParse("0.0.1"), testMetricMap)
+		c.Check(
+			resultMap["test_namespace"].columnMappings["metric_which_stays"].discard,
+			Equals,
+			false,
+		)
+		c.Check(
+			resultMap["test_namespace"].columnMappings["metric_which_discards"].discard,
+			Equals,
+			false,
+		)
+	}
+
+	{
+		// Update the map so the discard metric should be eliminated
+		discardable_metric := testMetricMap["test_namespace"]["metric_which_discards"]
+		discardable_metric.supportedVersions = semver.MustParseRange(">0.0.1")
+		testMetricMap["test_namespace"]["metric_which_discards"] = discardable_metric
+
+		// Discard metric should be discarded
+		resultMap := makeDescMap(semver.MustParse("0.0.1"), testMetricMap)
+		c.Check(
+			resultMap["test_namespace"].columnMappings["metric_which_stays"].discard,
+			Equals,
+			false,
+		)
+		c.Check(
+			resultMap["test_namespace"].columnMappings["metric_which_discards"].discard,
+			Equals,
+			true,
+		)
+	}
+
+	{
+		// Update the map so the discard metric should be kept but has a version
+		discardable_metric := testMetricMap["test_namespace"]["metric_which_discards"]
+		discardable_metric.supportedVersions = semver.MustParseRange(">0.0.1")
+		testMetricMap["test_namespace"]["metric_which_discards"] = discardable_metric
+
+		// Discard metric should be discarded
+		resultMap := makeDescMap(semver.MustParse("0.0.2"), testMetricMap)
+		c.Check(
+			resultMap["test_namespace"].columnMappings["metric_which_stays"].discard,
+			Equals,
+			false,
+		)
+		c.Check(
+			resultMap["test_namespace"].columnMappings["metric_which_discards"].discard,
+			Equals,
+			false,
+		)
+	}
+}