Merge pull request #1 from gojuno/multi-server-exporter

multi-server-exporter multi server exporter is introduced

Author: regeda

README.md

@@ -48,16 +48,19 @@ Package vendoring is handled with [`govendor`](https://github.com/kardianos/gove
   Path under which to expose metrics. Default is `/metrics`.
 
 * `disable-default-metrics`
-  Use only metrics supplied from `queries.yaml` via `--extend.query-path`
+  Use only metrics supplied from `queries.yaml` via `--extend.query-path`.
+
+* `disable-settings-metrics`
+  Use the flag if you don't want to scrape `pg_settings`.
 
 * `extend.query-path`
   Path to a YAML file containing custom queries to run. Check out [`queries.yaml`](queries.yaml)
   for examples of the format.
- 
+
 * `dumpmaps`
   Do not run - print the internal representation of the metric maps. Useful when debugging a custom
   queries file.
-  
+
 * `log.level`
   Set logging level: one of `debug`, `info`, `warn`, `error`, `fatal`
 
@@ -74,21 +77,23 @@ The following environment variables configure the exporter:
   URI may contain the username and password to connect with.
 
 * `DATA_SOURCE_URI`
-   an alternative to DATA_SOURCE_NAME which exclusively accepts the raw URI
+   an alternative to `DATA_SOURCE_NAME` which exclusively accepts the raw URI
    without a username and password component.
 
 * `DATA_SOURCE_USER`
   When using `DATA_SOURCE_URI`, this environment variable is used to specify
   the username.
+
 * `DATA_SOURCE_USER_FILE`
   The same, but reads the username from a file.
 
 * `DATA_SOURCE_PASS`
   When using `DATA_SOURCE_URI`, this environment variable is used to specify
   the password to connect with.
+
 * `DATA_SOURCE_PASS_FILE`
   The same as above but reads the password from a file.
-  
+
 * `PG_EXPORTER_WEB_LISTEN_ADDRESS`
   Address to listen on for web interface and telemetry. Default is `:9187`.
 
@@ -98,10 +103,13 @@ The following environment variables configure the exporter:
 * `PG_EXPORTER_DISABLE_DEFAULT_METRICS`
   Use only metrics supplied from `queries.yaml`. Value can be `true` or `false`. Default is `false`.
 
+* `PG_EXPORTER_DISABLE_SETTINGS_METRICS`
+  Use the flag if you don't want to scrape `pg_settings`. 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)
   for examples of the format.
-  
+
 Settings set by environment variables starting with `PG_` will be overwritten by the corresponding CLI flag if given.
 
 ### Setting the Postgres server's data source name
@@ -113,6 +121,10 @@ For running it locally on a default Debian/Ubuntu install, this will work (trans
 
     sudo -u postgres DATA_SOURCE_NAME="user=postgres host=/var/run/postgresql/ sslmode=disable" postgres_exporter
 
+Also, you can set a list of sources to scrape different instances from the one exporter setup. Just define a string separated by comma.
+
+    sudo -u postgres DATA_SOURCE_NAME="port=5432, port=6432" postgres_exporter
+
 See the [github.com/lib/pq](http://github.com/lib/pq) module for other ways to format the connection string.
 
 ### Adding new metrics
@@ -136,7 +148,7 @@ The -extend.query-path command-line argument specifies a YAML file containing ad
 Some examples are provided in [queries.yaml](queries.yaml).
 
 ### Disabling default metrics
-To work with non-officially-supported postgres versions you can try disabling (e.g. 8.2.15) 
+To work with non-officially-supported postgres versions you can try disabling (e.g. 8.2.15)
 or a variant of postgres (e.g. Greenplum) you can disable the default metrics with the `--disable-default-metrics`
 flag. This removes all built-in metrics, and uses only metrics defined by queries in the `queries.yaml` file you supply
 (so you must supply one, otherwise the exporter will return nothing but internal statuses and not your database).

cmd/postgres_exporter/pg_setting.go

@@ -1,8 +1,6 @@
 package main
 
 import (
-	"database/sql"
-	"errors"
 	"fmt"
 	"math"
 	"strconv"
@@ -13,29 +11,29 @@ import (
 )
 
 // Query the pg_settings view containing runtime variables
-func querySettings(ch chan<- prometheus.Metric, db *sql.DB) error {
-	log.Debugln("Querying pg_setting view")
+func querySettings(ch chan<- prometheus.Metric, server *Server) error {
+	log.Debugf("Querying pg_setting view on %q", server)
 
 	// pg_settings docs: https://www.postgresql.org/docs/current/static/view-pg-settings.html
 	//
 	// NOTE: If you add more vartypes here, you must update the supported
 	// types in normaliseUnit() below
 	query := "SELECT name, setting, COALESCE(unit, ''), short_desc, vartype FROM pg_settings WHERE vartype IN ('bool', 'integer', 'real');"
 
-	rows, err := db.Query(query)
+	rows, err := server.db.Query(query)
 	if err != nil {
-		return errors.New(fmt.Sprintln("Error running query on database: ", namespace, err))
+		return fmt.Errorf("Error running query on database %q: %s %v", server, namespace, err)
 	}
 	defer rows.Close() // nolint: errcheck
 
 	for rows.Next() {
 		s := &pgSetting{}
 		err = rows.Scan(&s.name, &s.setting, &s.unit, &s.shortDesc, &s.vartype)
 		if err != nil {
-			return errors.New(fmt.Sprintln("Error retrieving rows:", namespace, err))
+			return fmt.Errorf("Error retrieving rows on %q: %s %v", server, namespace, err)
 		}
 
-		ch <- s.metric()
+		ch <- s.metric(server.String())
 	}
 
 	return nil
@@ -47,7 +45,7 @@ type pgSetting struct {
 	name, setting, unit, shortDesc, vartype string
 }
 
-func (s *pgSetting) metric() prometheus.Metric {
+func (s *pgSetting) metric(server string) prometheus.Metric {
 	var (
 		err       error
 		name      = strings.Replace(s.name, ".", "_", -1)
@@ -79,7 +77,7 @@ func (s *pgSetting) metric() prometheus.Metric {
 	}
 
 	desc := newDesc(subsystem, name, shortDesc)
-	return prometheus.MustNewConstMetric(desc, prometheus.GaugeValue, val)
+	return prometheus.MustNewConstMetric(desc, prometheus.GaugeValue, val, server)
 }
 
 // TODO: fix linter override

cmd/postgres_exporter/pg_setting_test.go

@@ -25,7 +25,7 @@ var fixtures = []fixture{
 			unit: "seconds",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_seconds_fixture_metric_seconds\", help: \"Foo foo foo [Units converted to seconds.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_seconds_fixture_metric_seconds", help: "Foo foo foo [Units converted to seconds.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 5,
 	},
 	{
@@ -41,7 +41,7 @@ var fixtures = []fixture{
 			unit: "seconds",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_milliseconds_fixture_metric_seconds\", help: \"Foo foo foo [Units converted to seconds.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_milliseconds_fixture_metric_seconds", help: "Foo foo foo [Units converted to seconds.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 5,
 	},
 	{
@@ -57,7 +57,7 @@ var fixtures = []fixture{
 			unit: "bytes",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_eight_kb_fixture_metric_bytes\", help: \"Foo foo foo [Units converted to bytes.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_eight_kb_fixture_metric_bytes", help: "Foo foo foo [Units converted to bytes.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 139264,
 	},
 	{
@@ -73,7 +73,7 @@ var fixtures = []fixture{
 			unit: "bytes",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_16_kb_real_fixture_metric_bytes\", help: \"Foo foo foo [Units converted to bytes.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_16_kb_real_fixture_metric_bytes", help: "Foo foo foo [Units converted to bytes.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 49152,
 	},
 	{
@@ -89,7 +89,7 @@ var fixtures = []fixture{
 			unit: "bytes",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_16_mb_real_fixture_metric_bytes\", help: \"Foo foo foo [Units converted to bytes.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_16_mb_real_fixture_metric_bytes", help: "Foo foo foo [Units converted to bytes.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 5.0331648e+07,
 	},
 	{
@@ -105,7 +105,7 @@ var fixtures = []fixture{
 			unit: "bytes",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_32_mb_real_fixture_metric_bytes\", help: \"Foo foo foo [Units converted to bytes.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_32_mb_real_fixture_metric_bytes", help: "Foo foo foo [Units converted to bytes.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 1.00663296e+08,
 	},
 	{
@@ -121,7 +121,7 @@ var fixtures = []fixture{
 			unit: "bytes",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_64_mb_real_fixture_metric_bytes\", help: \"Foo foo foo [Units converted to bytes.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_64_mb_real_fixture_metric_bytes", help: "Foo foo foo [Units converted to bytes.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 2.01326592e+08,
 	},
 	{
@@ -137,7 +137,7 @@ var fixtures = []fixture{
 			unit: "",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_bool_on_fixture_metric\", help: \"Foo foo foo\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_bool_on_fixture_metric", help: "Foo foo foo", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 1,
 	},
 	{
@@ -153,7 +153,7 @@ var fixtures = []fixture{
 			unit: "",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_bool_off_fixture_metric\", help: \"Foo foo foo\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_bool_off_fixture_metric", help: "Foo foo foo", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 0,
 	},
 	{
@@ -169,7 +169,7 @@ var fixtures = []fixture{
 			unit: "seconds",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_special_minus_one_value_seconds\", help: \"foo foo foo [Units converted to seconds.]\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_special_minus_one_value_seconds", help: "foo foo foo [Units converted to seconds.]", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: -1,
 	},
 	{
@@ -185,7 +185,7 @@ var fixtures = []fixture{
 			unit: "",
 			err:  "",
 		},
-		d: "Desc{fqName: \"pg_settings_rds_rds_superuser_reserved_connections\", help: \"Sets the number of connection slots reserved for rds_superusers.\", constLabels: {}, variableLabels: []}",
+		d: `Desc{fqName: "pg_settings_rds_rds_superuser_reserved_connections", help: "Sets the number of connection slots reserved for rds_superusers.", constLabels: {}, variableLabels: [` + serverLabelName + `]}`,
 		v: 2,
 	},
 	{
@@ -233,7 +233,7 @@ func (s *PgSettingSuite) TestMetric(c *C) {
 
 	for _, f := range fixtures {
 		d := &dto.Metric{}
-		m := f.p.metric()
+		m := f.p.metric("")
 		m.Write(d) // nolint: errcheck
 
 		c.Check(m.Desc().String(), Equals, f.d)