telegraf/plugins/inputs/postgresql/postgresql.go

221 lines
5.3 KiB
Go

package postgresql
import (
"bytes"
"database/sql"
"fmt"
"regexp"
"sort"
"strings"
// register in driver.
_ "github.com/jackc/pgx/stdlib"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/inputs"
)
type Postgresql struct {
Address string
Databases []string
IgnoredDatabases []string
OrderedColumns []string
AllColumns []string
sanitizedAddress string
}
var ignoredColumns = map[string]bool{"stats_reset": true}
var sampleConfig = `
## specify address via a url matching:
## postgres://[pqgotest[:password]]@localhost[/dbname]\
## ?sslmode=[disable|verify-ca|verify-full]
## or a simple string:
## host=localhost user=pqotest password=... sslmode=... dbname=app_production
##
## All connection parameters are optional.
##
## Without the dbname parameter, the driver will default to a database
## with the same name as the user. This dbname is just for instantiating a
## connection with the server and doesn't restrict the databases we are trying
## to grab metrics for.
##
address = "host=localhost user=postgres sslmode=disable"
## A list of databases to explicitly ignore. If not specified, metrics for all
## databases are gathered. Do NOT use with the 'databases' option.
# ignored_databases = ["postgres", "template0", "template1"]
## A list of databases to pull metrics about. If not specified, metrics for all
## databases are gathered. Do NOT use with the 'ignored_databases' option.
# databases = ["app_production", "testing"]
`
func (p *Postgresql) SampleConfig() string {
return sampleConfig
}
func (p *Postgresql) Description() string {
return "Read metrics from one or many postgresql servers"
}
func (p *Postgresql) IgnoredColumns() map[string]bool {
return ignoredColumns
}
var localhost = "host=localhost sslmode=disable"
func (p *Postgresql) Gather(acc telegraf.Accumulator) error {
var (
err error
db *sql.DB
query string
)
if p.Address == "" || p.Address == "localhost" {
p.Address = localhost
}
if db, err = sql.Open("pgx", p.Address); err != nil {
return err
}
defer db.Close()
if len(p.Databases) == 0 && len(p.IgnoredDatabases) == 0 {
query = `SELECT * FROM pg_stat_database`
} else if len(p.IgnoredDatabases) != 0 {
query = fmt.Sprintf(`SELECT * FROM pg_stat_database WHERE datname NOT IN ('%s')`,
strings.Join(p.IgnoredDatabases, "','"))
} else {
query = fmt.Sprintf(`SELECT * FROM pg_stat_database WHERE datname IN ('%s')`,
strings.Join(p.Databases, "','"))
}
rows, err := db.Query(query)
if err != nil {
return err
}
defer rows.Close()
// grab the column information from the result
p.OrderedColumns, err = rows.Columns()
if err != nil {
return err
} else {
p.AllColumns = make([]string, len(p.OrderedColumns))
copy(p.AllColumns, p.OrderedColumns)
}
for rows.Next() {
err = p.accRow(rows, acc)
if err != nil {
return err
}
}
query = `SELECT * FROM pg_stat_bgwriter`
bg_writer_row, err := db.Query(query)
if err != nil {
return err
}
defer bg_writer_row.Close()
// grab the column information from the result
p.OrderedColumns, err = bg_writer_row.Columns()
if err != nil {
return err
} else {
for _, v := range p.OrderedColumns {
p.AllColumns = append(p.AllColumns, v)
}
}
for bg_writer_row.Next() {
err = p.accRow(bg_writer_row, acc)
if err != nil {
return err
}
}
sort.Strings(p.AllColumns)
return bg_writer_row.Err()
}
type scanner interface {
Scan(dest ...interface{}) error
}
var passwordKVMatcher, _ = regexp.Compile("password=\\S+ ?")
func (p *Postgresql) SanitizedAddress() (_ string, err error) {
var canonicalizedAddress string
if strings.HasPrefix(p.Address, "postgres://") || strings.HasPrefix(p.Address, "postgresql://") {
canonicalizedAddress, err = ParseURL(p.Address)
if err != nil {
return p.sanitizedAddress, err
}
} else {
canonicalizedAddress = p.Address
}
p.sanitizedAddress = passwordKVMatcher.ReplaceAllString(canonicalizedAddress, "")
return p.sanitizedAddress, err
}
func (p *Postgresql) accRow(row scanner, acc telegraf.Accumulator) error {
var columnVars []interface{}
var dbname bytes.Buffer
// this is where we'll store the column name with its *interface{}
columnMap := make(map[string]*interface{})
for _, column := range p.OrderedColumns {
columnMap[column] = new(interface{})
}
// populate the array of interface{} with the pointers in the right order
for i := 0; i < len(columnMap); i++ {
columnVars = append(columnVars, columnMap[p.OrderedColumns[i]])
}
// deconstruct array of variables and send to Scan
err := row.Scan(columnVars...)
if err != nil {
return err
}
if columnMap["datname"] != nil {
// extract the database name from the column map
dbname.WriteString((*columnMap["datname"]).(string))
} else {
dbname.WriteString("postgres")
}
var tagAddress string
tagAddress, err = p.SanitizedAddress()
if err != nil {
return err
}
tags := map[string]string{"server": tagAddress, "db": dbname.String()}
fields := make(map[string]interface{})
for col, val := range columnMap {
_, ignore := ignoredColumns[col]
if !ignore {
fields[col] = *val
}
}
acc.AddFields("postgresql", fields, tags)
return nil
}
func init() {
inputs.Add("postgresql", func() telegraf.Input {
return &Postgresql{}
})
}