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placement: add rule definitions #1834

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Oct 29, 2019
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37 changes: 37 additions & 0 deletions pkg/slice/slice.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,37 @@
// Copyright 2019 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package slice

import "reflect"

// AnyOf returns true if any element in the slice matches the predict func.
func AnyOf(s interface{}, p func(int) bool) bool {
l := reflect.ValueOf(s).Len()
for i := 0; i < l; i++ {
if p(i) {
return true
}
}
return false
}

// NoneOf returns true if no element in the slice matches the predict func.
func NoneOf(s interface{}, p func(int) bool) bool {
return !AnyOf(s, p)
}

// AllOf returns true if all elements in the slice match the predict func.
func AllOf(s interface{}, p func(int) bool) bool {
return NoneOf(s, func(i int) bool { return !p(i) })
}
51 changes: 51 additions & 0 deletions pkg/slice/slice_test.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,51 @@
// Copyright 2019 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package slice_test

import (
"testing"

. "github.com/pingcap/check"
"github.com/pingcap/pd/pkg/slice"
)

func Test(t *testing.T) {
TestingT(t)
}

var _ = Suite(&testSliceSuite{})

type testSliceSuite struct {
}

func (s *testSliceSuite) Test(c *C) {
tests := []struct {
a []int
anyOf bool
noneOf bool
allOf bool
}{
{[]int{}, false, true, true},
{[]int{1, 2, 3}, true, false, false},
{[]int{1, 3}, false, true, false},
{[]int{2, 2, 4}, true, false, true},
}

for _, t := range tests {
even := func(i int) bool { return t.a[i]%2 == 0 }
c.Assert(slice.AnyOf(t.a, even), Equals, t.anyOf)
c.Assert(slice.NoneOf(t.a, even), Equals, t.noneOf)
c.Assert(slice.AllOf(t.a, even), Equals, t.allOf)
}
}
86 changes: 86 additions & 0 deletions server/schedule/placement/label_constraint.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,86 @@
// Copyright 2019 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package placement

import (
"github.com/pingcap/pd/pkg/slice"
"github.com/pingcap/pd/server/core"
)

// LabelConstraintOp defines how a LabelConstraint matches a store. It can be one of
// 'in', 'notIn', 'exists', or 'notExists'.
type LabelConstraintOp string

const (
// In restricts the store label value should in the value list.
// If label does not exist, `in` is always false.
In LabelConstraintOp = "in"
// NotIn restricts the store label value should not in the value list.
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// If label does not exist, `notIn` is always true.
NotIn LabelConstraintOp = "notIn"
// Exists restricts the store should have the label.
Exists LabelConstraintOp = "exists"
// NotExists restricts the store should not have the label.
NotExists LabelConstraintOp = "notExists"
)

func validateOp(op LabelConstraintOp) bool {
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return op == In || op == NotIn || op == Exists || op == NotExists
}

// LabelConstraint is used to filter store when trying to place peer of a region.
type LabelConstraint struct {
Key string `json:"key,omitempty"`
Op LabelConstraintOp `json:"op,omitempty"`
Values []string `json:"values,omitempty"`
}

// MatchStore checks if a store matches the constraint.
func (c *LabelConstraint) MatchStore(store *core.StoreInfo) bool {
switch c.Op {
case In:
label := store.GetLabelValue(c.Key)
return label != "" && slice.AnyOf(c.Values, func(i int) bool { return c.Values[i] == label })
case NotIn:
label := store.GetLabelValue(c.Key)
return label == "" || slice.NoneOf(c.Values, func(i int) bool { return c.Values[i] == label })
case Exists:
return store.GetLabelValue(c.Key) != ""
case NotExists:
return store.GetLabelValue(c.Key) == ""
}
return false
}

// If a store has exclusiveLabels, it can only be selected when the label is
// exciplitly specified in constraints.
// TODO: move it to config.
var exclusiveLabels = []string{"engine"}

// MatchLabelConstraints checks if a store matches label constraints list.
func MatchLabelConstraints(store *core.StoreInfo, constraints []LabelConstraint) bool {
if store == nil {
return false
}

if slice.AnyOf(exclusiveLabels, func(i int) bool { // if there is any exclusive label that
label := exclusiveLabels[i]
return store.GetLabelValue(label) != "" && // ... the store has the label
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slice.NoneOf(constraints, func(i int) bool { return constraints[i].Key == label }) // ... but label is not in constraints
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}) {
return false // ... then the store should be ignored
}

return slice.AllOf(constraints, func(i int) bool { return constraints[i].MatchStore(store) })
}
101 changes: 101 additions & 0 deletions server/schedule/placement/label_constraint_test.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,101 @@
// Copyright 2019 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package placement

import (
"testing"

. "github.com/pingcap/check"
"github.com/pingcap/pd/server/core"
)

func TestPlacement(t *testing.T) {
TestingT(t)
}

var _ = Suite(&testLabelConstraintsSuite{})

type testLabelConstraintsSuite struct{}

func (s *testLabelConstraintsSuite) TestLabelConstraint(c *C) {
stores := []map[string]string{
{"zone": "zone1", "rack": "rack1"}, // 1
{"zone": "zone1", "rack": "rack2"}, // 2
{"zone": "zone2"}, // 3
{"zone": "zone1", "engine": "rocksdb", "disk": "hdd"}, // 4
{"rack": "rack1", "disk": "ssd"}, // 5
{"zone": "zone3"}, // 6
}
constraints := []LabelConstraint{
{Key: "zone", Op: "in", Values: []string{"zone1"}},
{Key: "zone", Op: "in", Values: []string{"zone1", "zone2"}},
{Key: "zone", Op: "notIn", Values: []string{"zone1"}},
{Key: "zone", Op: "notIn", Values: []string{"zone1", "zone2"}},
{Key: "zone", Op: "exists"},
{Key: "disk", Op: "notExists"},
}
expect := [][]int{
{1, 2, 4},
{1, 2, 3, 4},
{3, 5, 6},
{5, 6},
{1, 2, 3, 4, 6},
{1, 2, 3, 6},
}
for i, constraint := range constraints {
var matched []int
for j, store := range stores {
if constraint.MatchStore(core.NewStoreInfoWithLabel(uint64(j), 0, store)) {
matched = append(matched, j+1)
}
}
c.Assert(matched, DeepEquals, expect[i])
}
}

func (s *testLabelConstraintsSuite) TestLabelConstraints(c *C) {
stores := []map[string]string{
{}, // 1
{"k1": "v1"}, // 2
{"k1": "v2"}, // 3
{"k2": "v1"}, // 4
{"k2": "v2"}, // 5
{"engine": "e1"}, // 6
{"engine": "e2"}, // 7
{"k1": "v1", "k2": "v1"}, // 8
{"k2": "v2", "engine": "e1"}, // 9
{"k1": "v1", "k2": "v2", "engine": "e2"}, // 10
}
constraints := [][]LabelConstraint{
{},
{{Key: "engine", Op: "in", Values: []string{"e1", "e2"}}},
{{Key: "k1", Op: "notExists"}, {Key: "k2", Op: "exists"}},
{{Key: "engine", Op: "exists"}, {Key: "k1", Op: "in", Values: []string{"v1", "v2"}}, {Key: "k2", Op: "notIn", Values: []string{"v3"}}},
}
expect := [][]int{
{1, 2, 3, 4, 5, 8},
{6, 7, 9, 10},
{4, 5},
{10},
}
for i, cs := range constraints {
var matched []int
for j, store := range stores {
if MatchLabelConstraints(core.NewStoreInfoWithLabel(uint64(j), 0, store), cs) {
matched = append(matched, j+1)
}
}
c.Assert(matched, DeepEquals, expect[i])
}
}
98 changes: 98 additions & 0 deletions server/schedule/placement/rule.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,98 @@
// Copyright 2019 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package placement

import "sort"

// PeerRoleType is the expected peer type of the placement rule.
type PeerRoleType string

const (
// Voter can either match a leader peer or follower peer
Voter PeerRoleType = "voter"
// Leader matches a leader.
Leader PeerRoleType = "leader"
// Follower matches a follower.
Follower PeerRoleType = "follower"
// Learner matches a learner.
Learner PeerRoleType = "learner"
)

func validateRole(s PeerRoleType) bool {
return s == Voter || s == Leader || s == Follower || s == Learner
}

// Rule is the placement rule that can be checked against a region. When
// applying rules (apply means schedule regions to match selected rules), the
// apply order is defined by the tuple [GroupID, Index, ID].
type Rule struct {
GroupID string `json:"group_id"` // mark the source that add the rule
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BTW, I think it's better to unify the style of it in the future. We have both snake_case and kebab-case in our repo.

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em, so are you suggesting using kebab style?

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Maybe we can decide later, now both styles are used commonly.

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Of course.

ID string `json:"id"` // unique ID within a group
Index int `json:"index,omitempty"` // rule apply order in a group, rule with less ID is applied first when indexes are equal
Override bool `json:"override,omitempty"` // when it is true, all rules with less indexes are disabled
StartKey []byte `json:"-"` // range start key
StartKeyHex string `json:"start_key"` // hex format start key, for marshal/unmarshal
EndKey []byte `json:"-"` // range end key
EndKeyHex string `json:"end_key"` // hex format end key, for marshal/unmarshal
Role PeerRoleType `json:"role"` // expected role of the peers
Count int `json:"count"` // expected count of the peers
LabelConstraints []LabelConstraint `json:"label_constraints,omitempty"` // used to select stores to place peers
LocationLabels []string `json:"location_labels,omitempty"` // used to make peers isolated physically
}

// Key returns (groupID, ID) as the global unique key of a rule.
func (r Rule) Key() [2]string {
return [2]string{r.GroupID, r.ID}
}

// Rules are ordered by (GroupID, Index, ID).
func compareRule(a, b *Rule) int {
switch {
case a.GroupID < b.GroupID:
return -1
case a.GroupID > b.GroupID:
return 1
case a.Index < b.Index:
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return -1
case a.Index > b.Index:
return 1
case a.ID < b.ID:
return -1
case a.ID > b.ID:
return 1
default:
return 0
}
}

func sortRules(rules []*Rule) {
sort.Slice(rules, func(i, j int) bool { return compareRule(rules[i], rules[j]) < 0 })
}

// Sort Rules, trim concealed rules.
func prepareRulesForApply(rules []*Rule) []*Rule {
sortRules(rules)
res := rules[:0]
var i, j int
for i = 1; i < len(rules); i++ {
if rules[j].GroupID != rules[i].GroupID {
res = append(res, rules[j:i]...)
j = i
}
if rules[i].Override {
j = i
}
}
return append(res, rules[j:]...)
}
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