vendor/github.com/apigee-labs/transicator/replication/replicator_test.go

/*
Copyright 2016 The Transicator Authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package replication

import (
	"database/sql"
	"fmt"
	"time"

	"github.com/apigee-labs/transicator/common"
	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
)

var _ = Describe("Replicator tests", func() {
	It("Basic replication", func() {
		repl, err := CreateReplicator(dbURL, "unittestslot")
		Expect(err).Should(Succeed())
		repl.SetChangeFilter(filterChange)
		repl.Start()
		defer repl.Stop()
		// There may be duplicates, so always drain first
		drainReplication(repl)

		is, err := db.Prepare("insert into transicator_test (id, testid) values ($1, $2)")
		Expect(err).Should(Succeed())
		defer is.Close()

		_, err = is.Exec("basic replication", testID)
		Expect(err).Should(Succeed())

		var change *common.Change
		Eventually(repl.Changes()).Should(Receive(&change))
		Expect(change.NewRow["id"].Value).Should(Equal("basic replication"))
		Consistently(repl.Changes()).ShouldNot(Receive())

		tx, err := db.Begin()
		Expect(err).Should(Succeed())
		tis := tx.Stmt(is)

		_, err = tis.Exec("replication 1", testID)
		Expect(err).Should(Succeed())
		_, err = tis.Exec("replication 2", testID)
		Expect(err).Should(Succeed())

		err = tx.Commit()
		Expect(err).Should(Succeed())

		Eventually(repl.Changes()).Should(Receive(&change))
		Expect(change.NewRow["id"].Value).Should(Equal("replication 1"))

		Eventually(repl.Changes()).Should(Receive(&change))
		Expect(change.NewRow["id"].Value).Should(Equal("replication 2"))
		Consistently(repl.Changes()).ShouldNot(Receive())
	})

	It("Drop slot", func() {
		repl, err := CreateReplicator(dbURL, "droptestslot")
		Expect(err).Should(Succeed())
		repl.Start()
		// There may be duplicates, so always drain first
		drainReplication(repl)

		// Slot should be created pretty soon
		Eventually(func() string {
			row := db.QueryRow(
				"select slot_name from pg_replication_slots where slot_name = 'droptestslot'")
			var sn string
			err = row.Scan(&sn)
			Expect(err).Should(Succeed())
			return sn
		}).Should(Equal("droptestslot"))

		repl.StopAndDrop()

		// Slot should be destroyed pretty soon
		Eventually(func() error {
			row := db.QueryRow(
				"select slot_name from pg_replication_slots where slot_name = 'droptestslot'")
			var sn string
			return row.Scan(&sn)
		}, 5*time.Second).Should(MatchError(sql.ErrNoRows))
	})
})

func drainReplication(repl *Replicator) []*common.Change {
	// Just pull stuff until we get a bit of a delay
	var maxLSN uint64
	var ret []*common.Change
	timedOut := false

	for !timedOut {
		timeout := time.After(1 * time.Second)
		select {
		case <-timeout:
			timedOut = true
		case change := <-repl.Changes():
			Expect(change.Error).Should(Succeed())
			if change.CommitSequence > maxLSN {
				maxLSN = change.CommitSequence
			}
			ret = append(ret, change)
		}
	}

	fmt.Fprintf(GinkgoWriter, "Acknowledging %d\n", maxLSN)
	repl.Acknowledge(maxLSN)
	return ret
}