152 lines
3.4 KiB
Go
152 lines
3.4 KiB
Go
package postgresql
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import (
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"bytes"
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"database/sql"
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"fmt"
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"strings"
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"github.com/influxdb/telegraf/plugins"
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_ "github.com/lib/pq"
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)
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type Postgresql struct {
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Address string
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Databases []string
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OrderedColumns []string
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}
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var ignoredColumns = map[string]bool{"datid": true, "datname": true, "stats_reset": true}
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var sampleConfig = `
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# specify address via a url matching:
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# postgres://[pqgotest[:password]]@localhost[/dbname]?sslmode=[disable|verify-ca|verify-full]
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# or a simple string:
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# host=localhost user=pqotest password=... sslmode=... dbname=app_production
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#
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# All connection parameters are optional.
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#
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# Without the dbname parameter, the driver will default to a database
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# with the same name as the user. This dbname is just for instantiating a
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# connection with the server and doesn't restrict the databases we are trying
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# to grab metrics for.
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#
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address = "host=localhost user=postgres sslmode=disable"
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# A list of databases to pull metrics about. If not specified, metrics for all
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# databases are gathered.
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# databases = ["app_production", "testing"]
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`
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func (p *Postgresql) SampleConfig() string {
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return sampleConfig
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}
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func (p *Postgresql) Description() string {
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return "Read metrics from one or many postgresql servers"
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}
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func (p *Postgresql) IgnoredColumns() map[string]bool {
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return ignoredColumns
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}
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var localhost = "host=localhost sslmode=disable"
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func (p *Postgresql) Gather(acc plugins.Accumulator) error {
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var query string
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if p.Address == "" || p.Address == "localhost" {
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p.Address = localhost
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}
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db, err := sql.Open("postgres", p.Address)
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if err != nil {
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return err
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}
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defer db.Close()
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if len(p.Databases) == 0 {
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query = `SELECT * FROM pg_stat_database`
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} else {
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query = fmt.Sprintf(`SELECT * FROM pg_stat_database WHERE datname IN ('%s')`,
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strings.Join(p.Databases, "','"))
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}
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rows, err := db.Query(query)
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if err != nil {
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return err
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}
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defer rows.Close()
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// grab the column information from the result
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p.OrderedColumns, err = rows.Columns()
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if err != nil {
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return err
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}
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for rows.Next() {
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err = p.accRow(rows, acc)
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if err != nil {
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return err
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}
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}
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return rows.Err()
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}
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type scanner interface {
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Scan(dest ...interface{}) error
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}
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func (p *Postgresql) accRow(row scanner, acc plugins.Accumulator) error {
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var columnVars []interface{}
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var dbname bytes.Buffer
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// this is where we'll store the column name with its *interface{}
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columnMap := make(map[string]*interface{})
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for _, column := range p.OrderedColumns {
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columnMap[column] = new(interface{})
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}
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// populate the array of interface{} with the pointers in the right order
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for i := 0; i < len(columnMap); i++ {
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columnVars = append(columnVars, columnMap[p.OrderedColumns[i]])
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}
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// deconstruct array of variables and send to Scan
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err := row.Scan(columnVars...)
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if err != nil {
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return err
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}
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// extract the database name from the column map
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dbnameChars := (*columnMap["datname"]).([]uint8)
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for i := 0; i < len(dbnameChars); i++ {
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dbname.WriteString(string(dbnameChars[i]))
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}
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tags := map[string]string{"server": p.Address, "db": dbname.String()}
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fields := make(map[string]interface{})
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for col, val := range columnMap {
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_, ignore := ignoredColumns[col]
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if !ignore {
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fields[col] = *val
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}
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}
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acc.AddFields("postgresql", fields, tags)
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return nil
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}
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func init() {
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plugins.Add("postgresql", func() plugins.Plugin {
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return &Postgresql{}
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})
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}
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