package postgresql_extensible import ( "bytes" "fmt" "log" "strings" // register in driver. _ "github.com/jackc/pgx/stdlib" "github.com/influxdata/telegraf" "github.com/influxdata/telegraf/internal" "github.com/influxdata/telegraf/plugins/inputs" "github.com/influxdata/telegraf/plugins/inputs/postgresql" ) type Postgresql struct { postgresql.Service Databases []string AdditionalTags []string Query []struct { Sqlquery string Version int Withdbname bool Tagvalue string Measurement string } Debug bool } type query []struct { Sqlquery string Version int Withdbname bool Tagvalue string Measurement 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" ## connection configuration. ## maxlifetime - specify the maximum lifetime of a connection. ## default is forever (0s) max_lifetime = "0s" ## A list of databases to pull metrics about. If not specified, metrics for all ## databases are gathered. ## databases = ["app_production", "testing"] # ## A custom name for the database that will be used as the "server" tag in the ## measurement output. If not specified, a default one generated from ## the connection address is used. # outputaddress = "db01" # ## Define the toml config where the sql queries are stored ## New queries can be added, if the withdbname is set to true and there is no ## databases defined in the 'databases field', the sql query is ended by a ## 'is not null' in order to make the query succeed. ## Example : ## The sqlquery : "SELECT * FROM pg_stat_database where datname" become ## "SELECT * FROM pg_stat_database where datname IN ('postgres', 'pgbench')" ## because the databases variable was set to ['postgres', 'pgbench' ] and the ## withdbname was true. Be careful that if the withdbname is set to false you ## don't have to define the where clause (aka with the dbname) the tagvalue ## field is used to define custom tags (separated by commas) ## The optional "measurement" value can be used to override the default ## output measurement name ("postgresql"). # ## Structure : ## [[inputs.postgresql_extensible.query]] ## sqlquery string ## version string ## withdbname boolean ## tagvalue string (comma separated) ## measurement string [[inputs.postgresql_extensible.query]] sqlquery="SELECT * FROM pg_stat_database" version=901 withdbname=false tagvalue="" measurement="" [[inputs.postgresql_extensible.query]] sqlquery="SELECT * FROM pg_stat_bgwriter" version=901 withdbname=false tagvalue="postgresql.stats" ` 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 } func (p *Postgresql) Gather(acc telegraf.Accumulator) error { var ( err error sql_query string query_addon string db_version int query string tag_value string meas_name string columns []string ) // Retreiving the database version query = `select substring(setting from 1 for 3) as version from pg_settings where name='server_version_num'` if err = p.DB.QueryRow(query).Scan(&db_version); err != nil { db_version = 0 } // We loop in order to process each query // Query is not run if Database version does not match the query version. for i := range p.Query { sql_query = p.Query[i].Sqlquery tag_value = p.Query[i].Tagvalue if p.Query[i].Measurement != "" { meas_name = p.Query[i].Measurement } else { meas_name = "postgresql" } if p.Query[i].Withdbname { if len(p.Databases) != 0 { query_addon = fmt.Sprintf(` IN ('%s')`, strings.Join(p.Databases, "','")) } else { query_addon = " is not null" } } else { query_addon = "" } sql_query += query_addon if p.Query[i].Version <= db_version { rows, err := p.DB.Query(sql_query) if err != nil { acc.AddError(err) continue } defer rows.Close() // grab the column information from the result if columns, err = rows.Columns(); err != nil { acc.AddError(err) continue } p.AdditionalTags = nil if tag_value != "" { tag_list := strings.Split(tag_value, ",") for t := range tag_list { p.AdditionalTags = append(p.AdditionalTags, tag_list[t]) } } for rows.Next() { err = p.accRow(meas_name, rows, acc, columns) if err != nil { acc.AddError(err) break } } } } return nil } type scanner interface { Scan(dest ...interface{}) error } func (p *Postgresql) accRow(meas_name string, row scanner, acc telegraf.Accumulator, columns []string) error { var ( err error columnVars []interface{} dbname bytes.Buffer tagAddress string ) // this is where we'll store the column name with its *interface{} columnMap := make(map[string]*interface{}) for _, column := range columns { 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[columns[i]]) } // deconstruct array of variables and send to Scan if err = row.Scan(columnVars...); 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") } if tagAddress, err = p.SanitizedAddress(); err != nil { return err } // Process the additional tags tags := map[string]string{ "server": tagAddress, "db": dbname.String(), } fields := make(map[string]interface{}) COLUMN: for col, val := range columnMap { log.Printf("D! postgresql_extensible: column: %s = %T: %v\n", col, *val, *val) _, ignore := ignoredColumns[col] if ignore || *val == nil { continue } for _, tag := range p.AdditionalTags { if col != tag { continue } switch v := (*val).(type) { case string: tags[col] = v case []byte: tags[col] = string(v) case int64, int32, int: tags[col] = fmt.Sprintf("%d", v) default: log.Println("failed to add additional tag", col) } continue COLUMN } if v, ok := (*val).([]byte); ok { fields[col] = string(v) } else { fields[col] = *val } } acc.AddFields(meas_name, fields, tags) return nil } func init() { inputs.Add("postgresql_extensible", func() telegraf.Input { return &Postgresql{ Service: postgresql.Service{ MaxIdle: 1, MaxOpen: 1, MaxLifetime: internal.Duration{ Duration: 0, }, IsPgBouncer: false, }, } }) }