policies_test.go

// Copyright (c) 2015 The gocql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package gocql

import (
	"fmt"
	"net"
	"testing"
	"time"

	"github.com/hailocab/go-hostpool"
)

// Tests of the round-robin host selection policy implementation
func TestRoundRobinHostPolicy(t *testing.T) {
	policy := RoundRobinHostPolicy()

	hosts := [...]*HostInfo{
		{hostId: "0", peer: net.IPv4(0, 0, 0, 1)},
		{hostId: "1", peer: net.IPv4(0, 0, 0, 2)},
	}

	for _, host := range hosts {
		policy.AddHost(host)
	}

	// interleaved iteration should always increment the host
	iterA := policy.Pick(nil)
	if actual := iterA(); actual.Info() != hosts[0] {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actual.Info().HostID())
	}
	iterB := policy.Pick(nil)
	if actual := iterB(); actual.Info() != hosts[1] {
		t.Errorf("Expected hosts[1] but was hosts[%s]", actual.Info().HostID())
	}
	if actual := iterB(); actual.Info() != hosts[0] {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actual.Info().HostID())
	}
	if actual := iterA(); actual.Info() != hosts[1] {
		t.Errorf("Expected hosts[1] but was hosts[%s]", actual.Info().HostID())
	}

	iterC := policy.Pick(nil)
	if actual := iterC(); actual.Info() != hosts[0] {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actual.Info().HostID())
	}
	if actual := iterC(); actual.Info() != hosts[1] {
		t.Errorf("Expected hosts[1] but was hosts[%s]", actual.Info().HostID())
	}
}

// Tests of the token-aware host selection policy implementation with a
// round-robin host selection policy fallback.
func TestTokenAwareHostPolicy(t *testing.T) {
	policy := TokenAwareHostPolicy(RoundRobinHostPolicy())

	query := &Query{}

	iter := policy.Pick(nil)
	if iter == nil {
		t.Fatal("host iterator was nil")
	}
	actual := iter()
	if actual != nil {
		t.Fatalf("expected nil from iterator, but was %v", actual)
	}

	// set the hosts
	hosts := [...]*HostInfo{
		{peer: net.IPv4(10, 0, 0, 1), tokens: []string{"00"}},
		{peer: net.IPv4(10, 0, 0, 2), tokens: []string{"25"}},
		{peer: net.IPv4(10, 0, 0, 3), tokens: []string{"50"}},
		{peer: net.IPv4(10, 0, 0, 4), tokens: []string{"75"}},
	}
	for _, host := range hosts {
		policy.AddHost(host)
	}

	// the token ring is not setup without the partitioner, but the fallback
	// should work
	if actual := policy.Pick(nil)(); !actual.Info().Peer().Equal(hosts[0].peer) {
		t.Errorf("Expected peer 0 but was %s", actual.Info().Peer())
	}

	query.RoutingKey([]byte("30"))
	if actual := policy.Pick(query)(); !actual.Info().Peer().Equal(hosts[1].peer) {
		t.Errorf("Expected peer 1 but was %s", actual.Info().Peer())
	}

	policy.SetPartitioner("OrderedPartitioner")

	// now the token ring is configured
	query.RoutingKey([]byte("20"))
	iter = policy.Pick(query)
	if actual := iter(); !actual.Info().Peer().Equal(hosts[1].peer) {
		t.Errorf("Expected peer 1 but was %s", actual.Info().Peer())
	}
	// rest are round robin
	if actual := iter(); !actual.Info().Peer().Equal(hosts[2].peer) {
		t.Errorf("Expected peer 2 but was %s", actual.Info().Peer())
	}
	if actual := iter(); !actual.Info().Peer().Equal(hosts[3].peer) {
		t.Errorf("Expected peer 3 but was %s", actual.Info().Peer())
	}
	if actual := iter(); !actual.Info().Peer().Equal(hosts[0].peer) {
		t.Errorf("Expected peer 0 but was %s", actual.Info().Peer())
	}
}

// Tests of the host pool host selection policy implementation
func TestHostPoolHostPolicy(t *testing.T) {
	policy := HostPoolHostPolicy(hostpool.New(nil))

	hosts := []*HostInfo{
		{hostId: "0", peer: net.IPv4(10, 0, 0, 0)},
		{hostId: "1", peer: net.IPv4(10, 0, 0, 1)},
	}

	// Using set host to control the ordering of the hosts as calling "AddHost" iterates the map
	// which will result in an unpredictable ordering
	policy.(*hostPoolHostPolicy).SetHosts(hosts)

	// the first host selected is actually at [1], but this is ok for RR
	// interleaved iteration should always increment the host
	iter := policy.Pick(nil)
	actualA := iter()
	if actualA.Info().HostID() != "0" {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actualA.Info().HostID())
	}
	actualA.Mark(nil)

	actualB := iter()
	if actualB.Info().HostID() != "1" {
		t.Errorf("Expected hosts[1] but was hosts[%s]", actualB.Info().HostID())
	}
	actualB.Mark(fmt.Errorf("error"))

	actualC := iter()
	if actualC.Info().HostID() != "0" {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actualC.Info().HostID())
	}
	actualC.Mark(nil)

	actualD := iter()
	if actualD.Info().HostID() != "0" {
		t.Errorf("Expected hosts[0] but was hosts[%s]", actualD.Info().HostID())
	}
	actualD.Mark(nil)
}

func TestRoundRobinNilHostInfo(t *testing.T) {
	policy := RoundRobinHostPolicy()

	host := &HostInfo{hostId: "host-1"}
	policy.AddHost(host)

	iter := policy.Pick(nil)
	next := iter()
	if next == nil {
		t.Fatal("got nil host")
	} else if v := next.Info(); v == nil {
		t.Fatal("got nil HostInfo")
	} else if v.HostID() != host.HostID() {
		t.Fatalf("expected host %v got %v", host, v)
	}

	next = iter()
	if next != nil {
		t.Errorf("expected to get nil host got %+v", next)
		if next.Info() == nil {
			t.Fatalf("HostInfo is nil")
		}
	}
}

func TestTokenAwareNilHostInfo(t *testing.T) {
	policy := TokenAwareHostPolicy(RoundRobinHostPolicy())

	hosts := [...]*HostInfo{
		{peer: net.IPv4(10, 0, 0, 0), tokens: []string{"00"}},
		{peer: net.IPv4(10, 0, 0, 1), tokens: []string{"25"}},
		{peer: net.IPv4(10, 0, 0, 2), tokens: []string{"50"}},
		{peer: net.IPv4(10, 0, 0, 3), tokens: []string{"75"}},
	}
	for _, host := range hosts {
		policy.AddHost(host)
	}
	policy.SetPartitioner("OrderedPartitioner")

	query := &Query{}
	query.RoutingKey([]byte("20"))

	iter := policy.Pick(query)
	next := iter()
	if next == nil {
		t.Fatal("got nil host")
	} else if v := next.Info(); v == nil {
		t.Fatal("got nil HostInfo")
	} else if !v.Peer().Equal(hosts[1].peer) {
		t.Fatalf("expected peer 1 got %v", v.Peer())
	}

	// Empty the hosts to trigger the panic when using the fallback.
	for _, host := range hosts {
		policy.RemoveHost(host)
	}

	next = iter()
	if next != nil {
		t.Errorf("expected to get nil host got %+v", next)
		if next.Info() == nil {
			t.Fatalf("HostInfo is nil")
		}
	}
}

func TestCOWList_Add(t *testing.T) {
	var cow cowHostList

	toAdd := [...]net.IP{net.IPv4(0, 0, 0, 0), net.IPv4(1, 0, 0, 0), net.IPv4(2, 0, 0, 0)}

	for _, addr := range toAdd {
		if !cow.add(&HostInfo{peer: addr}) {
			t.Fatal("did not add peer which was not in the set")
		}
	}

	hosts := cow.get()
	if len(hosts) != len(toAdd) {
		t.Fatalf("expected to have %d hosts got %d", len(toAdd), len(hosts))
	}

	set := make(map[string]bool)
	for _, host := range hosts {
		set[string(host.Peer())] = true
	}

	for _, addr := range toAdd {
		if !set[string(addr)] {
			t.Errorf("addr was not in the host list: %q", addr)
		}
	}
}

// TestSimpleRetryPolicy makes sure that we only allow 1 + numRetries attempts
func TestSimpleRetryPolicy(t *testing.T) {
	q := &Query{}

	// this should allow a total of 3 tries.
	rt := &SimpleRetryPolicy{NumRetries: 2}

	cases := []struct {
		attempts int
		allow    bool
	}{
		{0, true},
		{1, true},
		{2, true},
		{3, false},
		{4, false},
		{5, false},
	}

	for _, c := range cases {
		q.attempts = c.attempts
		if c.allow && !rt.Attempt(q) {
			t.Fatalf("should allow retry after %d attempts", c.attempts)
		}
		if !c.allow && rt.Attempt(q) {
			t.Fatalf("should not allow retry after %d attempts", c.attempts)
		}
	}
}

func TestExponentialBackoffPolicy(t *testing.T) {
	// test with defaults
	sut := &ExponentialBackoffRetryPolicy{NumRetries: 2}

	cases := []struct {
		attempts int
		delay    time.Duration
	}{

		{1, 100 * time.Millisecond},
		{2, (2) * 100 * time.Millisecond},
		{3, (2 * 2) * 100 * time.Millisecond},
		{4, (2 * 2 * 2) * 100 * time.Millisecond},
	}
	for _, c := range cases {
		// test 100 times for each case
		for i := 0; i < 100; i++ {
			d := sut.napTime(c.attempts)
			if d < c.delay-(100*time.Millisecond)/2 {
				t.Fatalf("Delay %d less than jitter min of %d", d, c.delay-100*time.Millisecond/2)
			}
			if d > c.delay+(100*time.Millisecond)/2 {
				t.Fatalf("Delay %d greater than jitter max of %d", d, c.delay+100*time.Millisecond/2)
			}
		}
	}
}