Golang pq.Listener类代码示例

func waitForNotification(l *pq.Listener) {
	for {
		select {
		case notify := <-l.Notify:

			payload := strings.SplitN(notify.Extra, "|", 3)

			id, err := strconv.ParseInt(payload[0], 10, 64)
			if err != nil {
				panic(err)
			}
			var roomId int64
			roomId, err = strconv.ParseInt(payload[1], 10, 64)
			if err != nil {
				panic(err)
			}

			msg := models.GetMessage(id)

			revel.INFO.Printf("received notification with payload: '%d' '%d' '%s' '%s'\n", msg.Id, msg.RoomId, msg.Text, msg.ImageUrl)
			Publish(EVENT_MSG, int64(roomId), *msg)

		case <-time.After(200 * time.Millisecond):
			go func() {
				if err := l.Ping(); err != nil {
					panic(err)
				}
			}()
		}
	}
}

func waitForNotification(l *pq.Listener) {
	for {
		select {
		case n := <-l.Notify:
			fmt.Println("Received data from channel [", n.Channel, "] :")
			// Prepare notification payload for pretty print
			var prettyJSON bytes.Buffer
			err := json.Indent(&prettyJSON, []byte(n.Extra), "", "\t")
			if err != nil {
				fmt.Println("Error processing JSON: ", err)
				return
			}
			fmt.Println(string(prettyJSON.Bytes()))
			return
		case <-time.After(90 * time.Second):
			fmt.Println("Received no events for 90 seconds, checking connection")
			go func() {
				l.Ping()
			}()
			return
		}
	}
}

	"github.com/tedsuo/ifrit"
	"github.com/tedsuo/ifrit/ginkgomon"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
	. "github.com/sclevine/agouti/matchers"

	"github.com/cloudfoundry/gunk/urljoiner"
	"github.com/concourse/atc"
	"github.com/concourse/atc/db"
	"github.com/concourse/atc/event"
)

var _ = Describe("One-off Builds", func() {
	var atcProcess ifrit.Process
	var dbListener *pq.Listener
	var atcPort uint16
	var pipelineDBFactory db.PipelineDBFactory

	BeforeEach(func() {
		dbLogger := lagertest.NewTestLogger("test")
		postgresRunner.Truncate()
		dbConn = postgresRunner.Open()
		dbListener = pq.NewListener(postgresRunner.DataSourceName(), time.Second, time.Minute, nil)
		bus := db.NewNotificationsBus(dbListener, dbConn)
		sqlDB = db.NewSQL(dbLogger, dbConn, bus)
		pipelineDBFactory = db.NewPipelineDBFactory(dbLogger, dbConn, bus, sqlDB)

		atcProcess, atcPort = startATC(atcBin, 1)
	})

import (
	"time"

	"github.com/concourse/atc/db"
	"github.com/concourse/atc/db/fakes"
	"github.com/lib/pq"
	"github.com/pivotal-golang/lager/lagertest"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
)

var _ = Describe("PipelineDBFactory", func() {
	var dbConn db.Conn
	var listener *pq.Listener

	var pipelineDBFactory db.PipelineDBFactory

	var pipelinesDB *fakes.FakePipelinesDB

	BeforeEach(func() {
		postgresRunner.Truncate()

		dbConn = db.Wrap(postgresRunner.Open())

		listener = pq.NewListener(postgresRunner.DataSourceName(), time.Second, time.Minute, nil)
		Eventually(listener.Ping, 5*time.Second).ShouldNot(HaveOccurred())
		bus := db.NewNotificationsBus(listener, dbConn)

		pipelinesDB = new(fakes.FakePipelinesDB)

	"github.com/lib/pq"
	"github.com/pivotal-golang/lager/lagertest"
	"github.com/tedsuo/ifrit"
	"github.com/tedsuo/ifrit/ginkgomon"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
	"github.com/onsi/gomega/gexec"

	"github.com/concourse/atc"
	"github.com/concourse/atc/db"
)

var _ = Describe("Auth", func() {
	var atcProcess ifrit.Process
	var dbListener *pq.Listener
	var atcPort uint16

	BeforeEach(func() {
		logger := lagertest.NewTestLogger("test")
		postgresRunner.CreateTestDB()
		dbConn = postgresRunner.Open()
		dbListener = pq.NewListener(postgresRunner.DataSourceName(), time.Second, time.Minute, nil)
		bus := db.NewNotificationsBus(dbListener)
		sqlDB = db.NewSQL(logger, dbConn, bus)

		_, err := sqlDB.SaveConfig(atc.DefaultPipelineName, atc.Config{}, db.ConfigVersion(1), db.PipelineUnpaused)
		Ω(err).ShouldNot(HaveOccurred())

		atcBin, err := gexec.Build("github.com/concourse/atc/cmd/atc")
		Ω(err).ShouldNot(HaveOccurred())

func setupDatabaseListener() {
	if !checkDatabaseHandleValid(db) {
		return
	}

	//create/replace function for notifyPhoneNumber()
	if _, err := db.Exec(`CREATE or REPLACE FUNCTION notifyPhoneNumber() RETURNS trigger AS $$
 			BEGIN  
  			  IF TG_OP='DELETE' THEN
    				EXECUTE FORMAT('NOTIFY notifyphonenumber, ''%s''', OLD.PhoneNumber); 
  				ELSE
    				EXECUTE FORMAT('NOTIFY notifyphonenumber, ''%s''', NEW.PhoneNumber); 
  				END IF;
  			RETURN NULL;
 			END;  
		$$ LANGUAGE plpgsql;`); err != nil {
		log.Println(err)
	} else {
		log.Println("Successfully create/replace function notifyPhoneNumber()")
	}

	//check for trigger existence
	var triggerExist bool
	if err := db.QueryRow(`SELECT EXISTS(
		SELECT 1
			FROM pg_trigger
			WHERE tgname='inprogresschange')`).Scan(&triggerExist); err != nil {
		log.Println(err)
	}
	if !triggerExist {
		if _, err := db.Exec(`CREATE TRIGGER inprogresschange AFTER INSERT OR UPDATE OR DELETE
 			ON inprogress
 			FOR EACH ROW 
 			EXECUTE PROCEDURE notifyPhoneNumber();`); err != nil {
			log.Println(err)
		} else {
			log.Println("Successfully create trigger inprogresschange")
		}
	} else {
		log.Println("Trigger inprogresschange exists.")
	}

	//Create handler for logging listener errors
	reportProblem := func(ev pq.ListenerEventType, err error) {
		if err != nil {
			fmt.Println(err.Error())
		}
	}

	//Listen for table updates
	var listenerObj *pq.Listener
	listenerObj = pq.NewListener(os.Getenv("DATABASE_URL"), 10*time.Second, time.Minute, reportProblem)

	err := listenerObj.Listen("notifyphonenumber")
	if err != nil {
		log.Println(err)
	}

	//Find our session PID so we can ignore notifications from ourselves
	var pid int
	fmt.Println("Getting session PID...")
	if rows, err := db.Query(`SELECT * 
		FROM pg_stat_activity 
		WHERE pid = pg_backend_pid();`); err != nil {
		log.Println(err)
	} else {
		var i interface{} //empty interface to read unneeded columns into
		for rows.Next() {
			if err := rows.Scan(&i, &i, &pid, &i, &i, &i, &i, &i, &i, &i, &i, &i, &i, &i, &i, &i, &i, &i); err != nil {
				log.Println(err)
			} else {
				fmt.Println("Session PID:", pid)
			}
		}
	}

	//Monitor for noitification in background
	go func() {
		for {
			var notificationObj *pq.Notification
			notificationObj = <-listenerObj.Notify
			fmt.Printf("Backend PID %v\nChannel %v\nPayload %v\n", notificationObj.BePid, notificationObj.Channel, notificationObj.Extra)
			//Get updated row from database if the notifying PID is not this instance's PID
			if pid != notificationObj.BePid {
				if updatedRows := selectRowsFromTableByPhoneNumber("inprogress", notificationObj.Extra); updatedRows == nil {
					log.Println(err)
				} else {
					//We handle the possibility of deleted rows in laod pickups rows into memory since we can only enumerate over rows object once
					loadPickupRowsIntoMemory(&pickups, updatedRows, notificationObj)
				}
			}
		}
	}()
}