Fix exclude-databases for collector package

The pg_database collector was not respecting the --exclude-databases flag and causing problems where databases were not accessible. This now respects the list of databases to exclude.

- Adjusts the Collector create func to take a config struct instead of a logger. This allows more changes like this in the future. I figured we would need to do this at some point but I wasn't sure if we could hold off.
- Split the database size collection to a separate query when database is not excluded.
- Comment some probe code that was not useful/accurate

Signed-off-by: Joe Adams <github@joeadams.io>

cmd/postgres_exporter/main.go

@@ -14,8 +14,10 @@
 package main
 
 import (
+	"fmt"
 	"net/http"
 	"os"
+	"strings"
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
@@ -101,13 +103,16 @@ func main() {
 		os.Exit(1)
 	}
 
+	excludedDatabases := strings.Split(*excludeDatabases, ",")
+	logger.Log("msg", "Excluded databases", "databases", fmt.Sprintf("%v", excludedDatabases))
+
 	opts := []ExporterOpt{
 		DisableDefaultMetrics(*disableDefaultMetrics),
 		DisableSettingsMetrics(*disableSettingsMetrics),
 		AutoDiscoverDatabases(*autoDiscoverDatabases),
 		WithUserQueriesPath(*queriesPath),
 		WithConstantLabels(*constantLabelsList),
-		ExcludeDatabases(*excludeDatabases),
+		ExcludeDatabases(excludedDatabases),
 		IncludeDatabases(*includeDatabases),
 	}
 
@@ -128,6 +133,7 @@ func main() {
 
 	pe, err := collector.NewPostgresCollector(
 		logger,
+		excludedDatabases,
 		dsn,
 		[]string{},
 	)
@@ -143,7 +149,7 @@ func main() {
 		w.Write(landingPage)                                       // nolint: errcheck
 	})
 
-	http.HandleFunc("/probe", handleProbe(logger))
+	http.HandleFunc("/probe", handleProbe(logger, excludedDatabases))
 
 	srv := &http.Server{}
 	if err := web.ListenAndServe(srv, webConfig, logger); err != nil {

cmd/postgres_exporter/postgres_exporter.go

@@ -484,9 +484,9 @@ func AutoDiscoverDatabases(b bool) ExporterOpt {
 }
 
 // ExcludeDatabases allows to filter out result from AutoDiscoverDatabases
-func ExcludeDatabases(s string) ExporterOpt {
+func ExcludeDatabases(s []string) ExporterOpt {
 	return func(e *Exporter) {
-		e.excludeDatabases = strings.Split(s, ",")
+		e.excludeDatabases = s
 	}
 }
 

cmd/postgres_exporter/probe.go

@@ -16,7 +16,6 @@ package main
 import (
 	"fmt"
 	"net/http"
-	"time"
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
@@ -26,7 +25,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
-func handleProbe(logger log.Logger) http.HandlerFunc {
+func handleProbe(logger log.Logger, excludeDatabases []string) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		ctx := r.Context()
 		conf := c.GetConfig()
@@ -62,21 +61,21 @@ func handleProbe(logger log.Logger) http.HandlerFunc {
 
 		// TODO(@sysadmind): Timeout
 
-		probeSuccessGauge := prometheus.NewGauge(prometheus.GaugeOpts{
-			Name: "probe_success",
-			Help: "Displays whether or not the probe was a success",
-		})
-		probeDurationGauge := prometheus.NewGauge(prometheus.GaugeOpts{
-			Name: "probe_duration_seconds",
-			Help: "Returns how long the probe took to complete in seconds",
-		})
+		// probeSuccessGauge := prometheus.NewGauge(prometheus.GaugeOpts{
+		// 	Name: "probe_success",
+		// 	Help: "Displays whether or not the probe was a success",
+		// })
+		// probeDurationGauge := prometheus.NewGauge(prometheus.GaugeOpts{
+		// 	Name: "probe_duration_seconds",
+		// 	Help: "Returns how long the probe took to complete in seconds",
+		// })
 
 		tl := log.With(logger, "target", target)
 
-		start := time.Now()
+		// start := time.Now()
 		registry := prometheus.NewRegistry()
-		registry.MustRegister(probeSuccessGauge)
-		registry.MustRegister(probeDurationGauge)
+		// registry.MustRegister(probeSuccessGauge)
+		// registry.MustRegister(probeDurationGauge)
 
 		opts := []ExporterOpt{
 			DisableDefaultMetrics(*disableDefaultMetrics),
@@ -96,10 +95,10 @@ func handleProbe(logger log.Logger) http.HandlerFunc {
 		registry.MustRegister(exporter)
 
 		// Run the probe
-		pc, err := collector.NewProbeCollector(tl, registry, dsn)
+		pc, err := collector.NewProbeCollector(tl, excludeDatabases, registry, dsn)
 		if err != nil {
-			probeSuccessGauge.Set(0)
-			probeDurationGauge.Set(time.Since(start).Seconds())
+			// probeSuccessGauge.Set(0)
+			// probeDurationGauge.Set(time.Since(start).Seconds())
 			http.Error(w, err.Error(), http.StatusInternalServerError)
 			return
 		}
@@ -115,10 +114,6 @@ func handleProbe(logger log.Logger) http.HandlerFunc {
 
 		registry.MustRegister(pc)
 
-		duration := time.Since(start).Seconds()
-		probeDurationGauge.Set(duration)
-		probeSuccessGauge.Set(1)
-
 		// TODO check success, etc
 		h := promhttp.HandlerFor(registry, promhttp.HandlerOpts{})
 		h.ServeHTTP(w, r)