PMM-7344 Improve readme. Remove dublicate code.

Author: askomorokhov

README.md

@@ -34,7 +34,7 @@ docker run --net=host -e DATA_SOURCE_NAME="postgresql://postgres:password@localh
   Use the flag if you don't want to scrape `pg_settings`.
 
 * `auto-discover-databases`
-  Whether to discover the databases on a server dynamically.
+  Enable discovering databases automatically.
 
 * `extend.query-path`
   Path to a YAML file containing custom queries to run. Check out [`queries.yaml`](queries.yaml)
@@ -102,7 +102,7 @@ The following environment variables configure the exporter:
   Use the flag if you don't want to scrape `pg_settings`. Value can be `true` or `false`. Defauls is `false`.
 
 * `PG_EXPORTER_AUTO_DISCOVER_DATABASES`
-  Whether to discover the databases on a server dynamically. Value can be `true` or `false`. Defauls is `false`.
+  Enable discovering databases automatically. Value can be `true` or `false`. Defauls is `false`.
 
 * `PG_EXPORTER_EXTEND_QUERY_PATH`
   Path to a YAML file containing custom queries to run. Check out [`queries.yaml`](queries.yaml)

cmd/postgres_exporter/postgres_exporter.go

@@ -76,10 +76,6 @@ const (
 	serverLabelName = "server"
 )
 
-func init() {
-	prometheus.MustRegister(version.NewCollector("postgres_exporter"))
-}
-
 type MetricResolution string
 
 const (
@@ -1718,14 +1714,14 @@ func main() {
 		exporter.servers.Close()
 	}()
 
+	prometheus.MustRegister(exporter)
+
 	version.Branch = Branch
 	version.BuildDate = BuildDate
 	version.Revision = Revision
 	version.Version = VersionShort
 	prometheus.MustRegister(version.NewCollector("postgres_exporter"))
 
-	prometheus.MustRegister(exporter)
-
 	psCollector := prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{})
 	goCollector := prometheus.NewGoCollector()