Initial pgterminate code

terminator/terminator.go

@@ -0,0 +1,94 @@
+package terminator
+
+import (
+	"github.com/jouir/pgterminate/base"
+	"log"
+	"time"
+)
+
+// Terminator looks for sessions, filters actives and idles, terminate them and notify sessions channel
+// It ends itself gracefully when done channel is triggered
+type Terminator struct {
+	config   *base.Config
+	db       *base.Db
+	sessions chan base.Session
+	done     chan bool
+}
+
+// NewTerminator instanciates a Terminator
+func NewTerminator(ctx *base.Context) *Terminator {
+	return &Terminator{
+		config:   ctx.Config,
+		sessions: ctx.Sessions,
+		done:     ctx.Done,
+	}
+}
+
+// Run starts the Terminator
+func (t *Terminator) Run() {
+	t.db = base.NewDb(t.config.Dsn())
+	log.Println("Connecting to instance")
+	t.db.Connect()
+	defer t.terminate()
+
+	for {
+		select {
+		case <-t.done:
+			return
+		default:
+			sessions := t.db.Sessions()
+			if t.config.ActiveTimeout != 0 {
+				actives := activeSessions(sessions, t.config.ActiveTimeout)
+				go t.terminateAndNotify(actives)
+			}
+
+			if t.config.IdleTimeout != 0 {
+				idles := idleSessions(sessions, t.config.IdleTimeout)
+				go t.terminateAndNotify(idles)
+			}
+			time.Sleep(time.Duration(t.config.Interval*1000) * time.Millisecond)
+		}
+
+	}
+}
+
+// terminateAndNotify terminates a list of sessions and notifies channel
+func (t *Terminator) terminateAndNotify(sessions []base.Session) {
+	t.db.TerminateSessions(sessions)
+	for _, session := range sessions {
+		t.sessions <- session
+	}
+}
+
+// terminate terminates gracefully
+func (t *Terminator) terminate() {
+	log.Println("Disconnecting from instance")
+	t.db.Disconnect()
+}
+
+// activeSessions returns a list of active sessions
+// A session is active when state is "active" and backend has started before elapsed
+// seconds
+func activeSessions(sessions []base.Session, elapsed float64) (result []base.Session) {
+	for _, session := range sessions {
+		if session.State == "active" && session.QueryDuration > elapsed {
+			result = append(result, session)
+		}
+	}
+	return result
+}
+
+// idleSessions returns a list of idle sessions
+// A sessions is idle when state is "idle" and backend has started before elapsed seconds
+// and when state is "idle in transaction" or "idle in transaction (aborted)" and
+// transaction has started before elapsed seconds
+func idleSessions(sessions []base.Session, elapsed float64) (result []base.Session) {
+	for _, session := range sessions {
+		if session.State == "idle" && session.BackendDuration > elapsed {
+			result = append(result, session)
+		} else if (session.State == "idle in transaction" || session.State == "idle in transaction (aborted)") && session.XactDuration > elapsed {
+			result = append(result, session)
+		}
+	}
+	return result
+}