Merge pull request #50 from ringerc/pr-harden-pg-database-queries

Exclude template DBs from discovery and schema-qualify discovery query

exporter/server.go

@@ -202,10 +202,10 @@ func PostgresPrecheck(s *Server) (err error) {
 	var recovery bool
 	var datname, username string
 	var databases, namespaces, extensions []string
-	precheckSQL := `SELECT current_catalog, current_user, pg_is_in_recovery(),       
-	(SELECT array_agg(datname) AS databases FROM pg_database),
-	(SELECT array_agg(nspname) AS namespaces FROM pg_namespace),
-	(SELECT array_agg(extname) AS extensions FROM pg_extension);`
+	precheckSQL := `SELECT current_catalog, current_user, pg_catalog.pg_is_in_recovery(),
+	(SELECT pg_catalog.array_agg(d.datname) AS databases FROM pg_catalog.pg_database d WHERE d.datallowconn AND NOT d.datistemplate),
+	(SELECT pg_catalog.array_agg(n.nspname) AS namespaces FROM pg_catalog.pg_namespace n),
+	(SELECT pg_catalog.array_agg(e.extname) AS extensions FROM pg_catalog.pg_extension e);`
 	ctx, cancel2 := context.WithTimeout(context.Background(), s.GetConnectTimeout())
 	defer cancel2()
 	//if err = s.DB.QueryRowContext(ctx, precheckSQL).Scan(&datname, &username, &recovery, &databases, &namespaces, &extensions); err != nil {