fix: set sensible defaults

- fix sensible defaults for max and max idle connections
- changed github action which was not setting the proper version at
  build time.

Author: alessio-form3

.github/workflows/ci.yaml

@@ -31,10 +31,10 @@ jobs:
         uses: actions/setup-go@v5
         with:
           go-version-file: go.mod
-      - name: Build
-        run: make crossbuild
       - name: Set version
         run: echo "${{ needs.calculate-tag.outputs.tag }}" | sed s/v//g > VERSION
+      - name: Build
+        run: make crossbuild
       - name: Package
         run: make crossbuild-tarballs
       - name: Archive artifacts

VERSION

@@ -57,8 +57,8 @@ var (
 	excludeDatabases       = kingpin.Flag("exclude-databases", "A list of databases to remove when autoDiscoverDatabases is enabled (DEPRECATED)").Default("").Envar("PG_EXPORTER_EXCLUDE_DATABASES").String()
 	includeDatabases       = kingpin.Flag("include-databases", "A list of databases to include when autoDiscoverDatabases is enabled (DEPRECATED)").Default("").Envar("PG_EXPORTER_INCLUDE_DATABASES").String()
 	metricPrefix           = kingpin.Flag("metric-prefix", "A metric prefix can be used to have non-default (not \"pg\") prefixes for each of the metrics").Default("pg").Envar("PG_EXPORTER_METRIC_PREFIX").String()
-	maxOpenConnections     = kingpin.Flag("max-connections", "the maximum number of opened connections").Default("-1").Envar("PG_MAX_CONNECTIONS").Int()
-	maxIdleConnections     = kingpin.Flag("max-idle-connections", "the maximum number of idle connections").Default("-1").Envar("PG_MAX_IDLE_CONNECTIONS").Int()
+	maxOpenConnections     = kingpin.Flag("max-connections", "the maximum number of opened connections").Default("10").Envar("PG_MAX_CONNECTIONS").Int()
+	maxIdleConnections     = kingpin.Flag("max-idle-connections", "the maximum number of idle connections").Default("5").Envar("PG_MAX_IDLE_CONNECTIONS").Int()
 	collectorTimeout       = kingpin.Flag("collector-timeout", "the single collector scrape timeout").Default("10s").Envar("PG_COLLECTOR_TIMEOUT").Duration()
 	logger                 = log.NewNopLogger()
 )

cmd/postgres_exporter/main.go

@@ -540,7 +540,12 @@ func NewExporter(dsn []string, opts ...ExporterOpt) *Exporter {
 	}
 
 	e.setupInternalMetrics()
-	e.servers = NewServers(ServerWithLabels(e.constantLabels))
+	e.servers = NewServers(
+		ServerWithLabels(e.constantLabels),
+		ServerWithMaxIdleConnections(*maxIdleConnections),
+		ServerWithMaxOpenConnections(*maxOpenConnections),
+		ServerWithScrapeTimeout(e.scrapeTimeout),
+	)
 
 	return e
 }