From 00c99ec3738ab0ecccb1e6700256c8cc1c4f5b65 Mon Sep 17 00:00:00 2001
From: Evan Phoenix <evan@phx.io>
Date: Mon, 18 May 2015 11:54:11 -0700
Subject: [PATCH] Add mysql plugin

---
 plugins/mysql/mysql.go      | 134 ++++++++++++++++++++++++++++++++++++
 plugins/mysql/mysql_test.go |  68 ++++++++++++++++++
 2 files changed, 202 insertions(+)
 create mode 100644 plugins/mysql/mysql.go
 create mode 100644 plugins/mysql/mysql_test.go

diff --git a/plugins/mysql/mysql.go b/plugins/mysql/mysql.go
new file mode 100644
index 000000000..44d28b715
--- /dev/null
+++ b/plugins/mysql/mysql.go
@@ -0,0 +1,134 @@
+package mysql
+
+import (
+	"database/sql"
+	"strconv"
+	"strings"
+
+	_ "github.com/go-sql-driver/mysql"
+	"github.com/influxdb/tivan/plugins"
+)
+
+type Server struct {
+	Address string
+}
+
+type Mysql struct {
+	Disabled bool
+	Servers  []*Server
+}
+
+var localhost = &Server{}
+
+func (m *Mysql) Gather(acc plugins.Accumulator) error {
+	if m.Disabled {
+		return nil
+	}
+
+	if len(m.Servers) == 0 {
+		// if we can't get stats in this case, thats fine, don't report
+		// an error.
+		m.gatherServer(localhost, acc)
+		return nil
+	}
+
+	for _, serv := range m.Servers {
+		err := m.gatherServer(serv, acc)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+type mapping struct {
+	onServer string
+	inExport string
+}
+
+var mappings = []*mapping{
+	{
+		onServer: "Bytes_",
+		inExport: "mysql_bytes_",
+	},
+	{
+		onServer: "Com_",
+		inExport: "mysql_commands_",
+	},
+	{
+		onServer: "Handler_",
+		inExport: "mysql_handler_",
+	},
+	{
+		onServer: "Innodb_",
+		inExport: "mysql_innodb_",
+	},
+	{
+		onServer: "Threads_",
+		inExport: "mysql_threads_",
+	},
+}
+
+func (m *Mysql) gatherServer(serv *Server, acc plugins.Accumulator) error {
+	db, err := sql.Open("mysql", serv.Address)
+	if err != nil {
+		return err
+	}
+
+	defer db.Close()
+
+	rows, err := db.Query(`SHOW /*!50002 GLOBAL */ STATUS`)
+	if err != nil {
+		return nil
+	}
+
+	for rows.Next() {
+		var name string
+		var val interface{}
+
+		err = rows.Scan(&name, &val)
+		if err != nil {
+			return err
+		}
+
+		var found bool
+
+		for _, mapped := range mappings {
+			if strings.HasPrefix(name, mapped.onServer) {
+				i, _ := strconv.Atoi(string(val.([]byte)))
+				acc.Add(mapped.inExport+name[len(mapped.onServer):], i, nil)
+				found = true
+			}
+		}
+
+		if found {
+			continue
+		}
+
+		switch name {
+		case "Queries":
+			i, err := strconv.ParseInt(string(val.([]byte)), 10, 64)
+			if err != nil {
+				return err
+			}
+
+			acc.Add("mysql_queries", i, nil)
+		case "Slow_queries":
+			i, err := strconv.ParseInt(string(val.([]byte)), 10, 64)
+			if err != nil {
+				return err
+			}
+
+			acc.Add("mysql_slow_queries", i, nil)
+		}
+	}
+
+	return nil
+}
+
+func init() {
+	plugins.Add("mysql", func() plugins.Plugin {
+		return &Mysql{}
+	})
+}
diff --git a/plugins/mysql/mysql_test.go b/plugins/mysql/mysql_test.go
new file mode 100644
index 000000000..63c25b543
--- /dev/null
+++ b/plugins/mysql/mysql_test.go
@@ -0,0 +1,68 @@
+package mysql
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/influxdb/tivan/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMysqlGeneratesMetrics(t *testing.T) {
+	m := &Mysql{
+		Servers: []*Server{
+			{
+				Address: "",
+			},
+		},
+	}
+
+	var acc testutil.Accumulator
+
+	err := m.Gather(&acc)
+	require.NoError(t, err)
+
+	prefixes := []struct {
+		prefix string
+		count  int
+	}{
+		{"mysql_commands", 141},
+		{"mysql_handler", 18},
+		{"mysql_bytes", 2},
+		{"mysql_innodb", 51},
+		{"mysql_threads", 4},
+	}
+
+	intMetrics := []string{
+		"mysql_queries",
+		"mysql_slow_queries",
+	}
+
+	for _, prefix := range prefixes {
+		var count int
+
+		for _, p := range acc.Points {
+			if strings.HasPrefix(p.Name, prefix.prefix) {
+				count++
+			}
+		}
+
+		assert.Equal(t, prefix.count, count)
+	}
+
+	for _, metric := range intMetrics {
+		assert.True(t, acc.HasIntValue(metric))
+	}
+}
+
+func TestMysqlDefaultsToLocal(t *testing.T) {
+	m := &Mysql{}
+
+	var acc testutil.Accumulator
+
+	err := m.Gather(&acc)
+	require.NoError(t, err)
+
+	assert.True(t, len(acc.Points) > 0)
+}