76 lines
2.2 KiB
Go
76 lines
2.2 KiB
Go
package base
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import (
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"database/sql"
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"github.com/lib/pq"
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"strconv"
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)
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const (
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maxQueryLength = 1000
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)
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// Db centralizes connection to the database
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type Db struct {
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dsn string
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conn *sql.DB
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}
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// NewDb creates a Db object
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func NewDb(dsn string) *Db {
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return &Db{
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dsn: dsn,
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}
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}
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// Connect connects to the instance and ping it to ensure connection is working
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func (db *Db) Connect() {
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conn, err := sql.Open("postgres", db.dsn)
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Panic(err)
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err = conn.Ping()
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Panic(err)
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db.conn = conn
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}
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// Disconnect ends connection cleanly
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func (db *Db) Disconnect() {
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err := db.conn.Close()
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Panic(err)
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}
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// Sessions connects to the database and returns current sessions
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func (db *Db) Sessions() (sessions []Session) {
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query := `select pid as pid, usename as user, datname as db, host(client_addr)::text || ':' || client_port::text as client, state as state, substring(query from 1 for ` + strconv.Itoa(maxQueryLength) + `) as query, coalesce(extract(epoch from now() - backend_start), 0) as "backendDuration", coalesce(extract(epoch from now() - xact_start), 0) as "xactDuration", coalesce(extract(epoch from now() - query_start), 0) as "queryDuration" from pg_catalog.pg_stat_activity where pid <> pg_backend_pid();`
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rows, err := db.conn.Query(query)
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Panic(err)
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defer rows.Close()
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for rows.Next() {
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var pid sql.NullInt64
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var user, db, client, state, query sql.NullString
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var backendDuration, xactDuration, queryDuration float64
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err := rows.Scan(&pid, &user, &db, &client, &state, &query, &backendDuration, &xactDuration, &queryDuration)
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Panic(err)
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if pid.Valid && user.Valid && db.Valid && client.Valid && state.Valid && query.Valid {
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sessions = append(sessions, NewSession(pid.Int64, user.String, db.String, client.String, state.String, query.String, backendDuration, xactDuration, queryDuration))
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}
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}
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return sessions
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}
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// TerminateSessions terminates a list of sessions
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func (db *Db) TerminateSessions(sessions []Session) {
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var pids []int64
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for _, session := range sessions {
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pids = append(pids, session.Pid)
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}
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if len(pids) > 0 {
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query := `select pg_terminate_backend(pid) from pg_stat_activity where pid = any($1);`
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_, err := db.conn.Exec(query, pq.Array(pids))
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Panic(err)
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}
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}
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