93 lines
2.1 KiB
Go
93 lines
2.1 KiB
Go
package mysql
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import (
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"context"
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"database/sql"
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"strconv"
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"time"
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_ "github.com/go-sql-driver/mysql"
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"bugs.watch/agent/internal/aggregate"
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)
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// Collector queries MySQL global status each sample interval.
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// All queries run under a 3-second timeout; any failure is silently skipped.
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type Collector struct {
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db *sql.DB
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prevSlowQueries uint64
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hasPrev bool
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}
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func New(dsn string) (*Collector, error) {
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db, err := sql.Open("mysql", dsn)
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if err != nil {
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return nil, err
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}
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db.SetMaxOpenConns(2)
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db.SetMaxIdleConns(1)
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db.SetConnMaxLifetime(5 * time.Minute)
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return &Collector{db: db}, nil
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}
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func (c *Collector) Name() string { return "mysql" }
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func (c *Collector) Close() { c.db.Close() }
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func (c *Collector) Collect(window *aggregate.Window) {
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ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
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defer cancel()
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rows, err := c.db.QueryContext(ctx,
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"SHOW GLOBAL STATUS WHERE Variable_name IN ('Threads_connected','Threads_running','Slow_queries')",
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)
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if err != nil {
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return
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}
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defer rows.Close()
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vars := make(map[string]uint64, 3)
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for rows.Next() {
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var name, raw string
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if err := rows.Scan(&name, &raw); err != nil {
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continue
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}
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if v, err := strconv.ParseUint(raw, 10, 64); err == nil {
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vars[name] = v
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}
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}
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if err := rows.Err(); err != nil {
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return
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}
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var maxConn uint64
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if err := c.db.QueryRowContext(ctx, "SELECT @@max_connections").Scan(&maxConn); err != nil || maxConn == 0 {
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maxConn = 1
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}
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connPct := float64(vars["Threads_connected"]) / float64(maxConn) * 100
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window.AddDBConnPct(connPct)
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window.AddDBThreadsRunning(float64(vars["Threads_running"]))
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slow := vars["Slow_queries"]
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if c.hasPrev {
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var delta uint64
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if slow >= c.prevSlowQueries {
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delta = slow - c.prevSlowQueries
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}
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window.AddDBSlowQueriesDelta(delta)
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}
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c.prevSlowQueries = slow
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c.hasPrev = true
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var sizeBytes uint64
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err = c.db.QueryRowContext(ctx,
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"SELECT COALESCE(SUM(data_length + index_length), 0)"+
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" FROM information_schema.tables"+
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" WHERE table_schema NOT IN ('information_schema','performance_schema','mysql','sys')",
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).Scan(&sizeBytes)
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if err == nil {
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window.SetDBSizeBytes(sizeBytes)
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}
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}
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