PMM-11267: Add collector to gather plugins installed on mysql (#113)

* PMM-11267: Add collector to gather plugins installed on mysql

* PMM-11267 trigger actions

---------

Co-authored-by: Alex Tymchuk <alexander.tymchuk@percona.com>
Co-authored-by: Alexey Mukas <91831719+ritbl@users.noreply.github.com>

README.md

@@ -59,6 +59,7 @@ collect.engine_innodb_status                                 | 5.1           | C
 collect.engine_tokudb_status                                 | 5.6           | Collect from SHOW ENGINE TOKUDB STATUS.
 collect.global_status                                        | 5.1           | Collect from SHOW GLOBAL STATUS (Enabled by default)
 collect.global_variables                                     | 5.1           | Collect from SHOW GLOBAL VARIABLES (Enabled by default)
+collect.plugins                                              | 5.1           | Collect from SHOW PLUGINS
 collect.info_schema.clientstats                              | 5.5           | If running with userstat=1, set to true to collect client statistics.
 collect.info_schema.innodb_metrics                           | 5.6           | Collect metrics from information_schema.innodb_metrics.
 collect.info_schema.innodb_tablespaces                       | 5.7           | Collect metrics from information_schema.innodb_sys_tablespaces.

collector/plugins.go

@@ -0,0 +1,70 @@
+package collector
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	pluginsQuery = `SHOW PLUGINS`
+)
+
+var (
+	pluginDescription = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "plugin"),
+		"MySQL plugin",
+		[]string{"name", "status", "type", "library", "license"}, nil,
+	)
+)
+
+type plugin struct {
+	Name    sql.NullString
+	Status  sql.NullString
+	Type    sql.NullString
+	Library sql.NullString
+	License sql.NullString
+}
+
+// ScrapePlugins collects from `SHOW PLUGINS`.
+type ScrapePlugins struct{}
+
+// Name of the Scraper. Should be unique.
+func (ScrapePlugins) Name() string {
+	return "plugins"
+}
+
+// Help describes the role of the Scraper.
+func (ScrapePlugins) Help() string {
+	return "Collect from SHOW PLUGINS"
+}
+
+// Version of MySQL from which scraper is available.
+func (ScrapePlugins) Version() float64 {
+	return 5.1
+}
+
+func (ScrapePlugins) Scrape(ctx context.Context, db *sql.DB, ch chan<- prometheus.Metric, logger log.Logger) error {
+	showPluginsRows, err := db.QueryContext(ctx, pluginsQuery)
+	if err != nil {
+		return err
+	}
+	defer showPluginsRows.Close()
+	for showPluginsRows.Next() {
+		var pluginVal plugin
+		if err := showPluginsRows.Scan(&pluginVal.Name, &pluginVal.Status, &pluginVal.Type, &pluginVal.Library, &pluginVal.License); err != nil {
+			return err
+		}
+		ch <- prometheus.MustNewConstMetric(
+			pluginDescription, prometheus.GaugeValue, 1,
+			pluginVal.Name.String, pluginVal.Status.String, pluginVal.Type.String, pluginVal.Library.String, pluginVal.License.String,
+		)
+	}
+
+	return nil
+}
+
+// check interface
+var _ Scraper = ScrapePlugins{}

collector/plugins_test.go

@@ -0,0 +1,50 @@
+package collector
+
+import (
+	"context"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/smartystreets/goconvey/convey"
+)
+
+func TestScrapePlugins(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("error opening a stub database connection: %s", err)
+	}
+	defer db.Close()
+	columns := []string{"Name", "Status", "Type", "Library", "License"}
+	rows := sqlmock.NewRows(columns).
+		AddRow("INNODB_SYS_COLUMNS", "ACTIVE", "INFORMATION SCHEMA", nil, "GPL").
+		AddRow("MRG_MYISAM", "ACTIVE", "STORAGE ENGINE", nil, "GPL").
+		AddRow(nil, nil, nil, nil, nil)
+	mock.ExpectQuery(sanitizeQuery(pluginsQuery)).WillReturnRows(rows)
+
+	ch := make(chan prometheus.Metric)
+	go func() {
+		if err = (ScrapePlugins{}).Scrape(context.Background(), db, ch, log.NewNopLogger()); err != nil {
+			t.Errorf("error calling function on test: %s", err)
+		}
+		close(ch)
+	}()
+	counterExpected := []MetricResult{
+		{labels: labelMap{"name": "INNODB_SYS_COLUMNS", "status": "ACTIVE", "type": "INFORMATION SCHEMA", "library": "", "license": "GPL"}, value: 1, metricType: dto.MetricType_GAUGE},
+		{labels: labelMap{"name": "MRG_MYISAM", "status": "ACTIVE", "type": "STORAGE ENGINE", "library": "", "license": "GPL"}, value: 1, metricType: dto.MetricType_GAUGE},
+		{labels: labelMap{"name": "", "status": "", "type": "", "library": "", "license": ""}, value: 1, metricType: dto.MetricType_GAUGE},
+	}
+	convey.Convey("Metrics comparison", t, func() {
+		for _, expect := range counterExpected {
+			got := readMetric(<-ch)
+			convey.So(got, convey.ShouldResemble, expect)
+		}
+	})
+
+	// Ensure all SQL queries were executed
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled exceptions: %s", err)
+	}
+}

mysqld_exporter.go

@@ -31,8 +31,6 @@ import (
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
 	"github.com/go-sql-driver/mysql"
-	"github.com/percona/mysqld_exporter/collector"
-	pcl "github.com/percona/mysqld_exporter/percona/perconacollector"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/prometheus/common/promlog"
@@ -42,6 +40,9 @@ import (
 	webflag "github.com/prometheus/exporter-toolkit/web/kingpinflag"
 	"gopkg.in/alecthomas/kingpin.v2"
 	"gopkg.in/ini.v1"
+
+	"github.com/percona/mysqld_exporter/collector"
+	pcl "github.com/percona/mysqld_exporter/percona/perconacollector"
 )
 
 var (
@@ -158,6 +159,7 @@ var scrapers = map[collector.Scraper]bool{
 	pcl.ScrapeGlobalStatus{}:                              false,
 	collector.ScrapeGlobalStatus{}:                        false,
 	collector.ScrapeGlobalVariables{}:                     false,
+	collector.ScrapePlugins{}:                             false,
 	collector.ScrapeSlaveStatus{}:                         false,
 	pcl.ScrapeProcesslist{}:                               false,
 	collector.ScrapeProcesslist{}:                         false,
@@ -224,6 +226,7 @@ var scrapersMr = map[collector.Scraper]struct{}{
 // TODO Remove
 var scrapersLr = map[collector.Scraper]struct{}{
 	collector.ScrapeGlobalVariables{}:             {},
+	collector.ScrapePlugins{}:                     {},
 	collector.ScrapeTableSchema{}:                 {},
 	collector.ScrapeAutoIncrementColumns{}:        {},
 	collector.ScrapeBinlogSize{}:                  {},