Implement voluntary exits pool (#4610)

beacon-chain/operations/voluntaryexits/BUILD.bazel

@@ -0,0 +1,31 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "doc.go",
+        "service.go",
+    ],
+    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits",
+    visibility = ["//beacon-chain:__subpackages__"],
+    deps = [
+        "//beacon-chain/blockchain:go_default_library",
+        "//beacon-chain/core/helpers:go_default_library",
+        "//shared/params:go_default_library",
+        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    size = "small",
+    srcs = ["service_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//beacon-chain/blockchain/testing:go_default_library",
+        "//proto/beacon/p2p/v1:go_default_library",
+        "//shared/params:go_default_library",
+        "@com_github_gogo_protobuf//proto:go_default_library",
+        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
+    ],
+)

beacon-chain/operations/voluntaryexits/doc.go

@@ -0,0 +1,2 @@
+// Package voluntaryexits defines the operations management of voluntary exits.
+package voluntaryexits

beacon-chain/operations/voluntaryexits/service.go

@@ -0,0 +1,94 @@
+package voluntaryexits
+
+import (
+	"context"
+	"sort"
+	"sync"
+
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/beacon-chain/blockchain"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// Pool implements a struct to maintain pending and recently included voluntary exits. This pool
+// is used by proposers to insert into new blocks.
+type Pool struct {
+	lock     sync.RWMutex
+	pending  []*ethpb.SignedVoluntaryExit
+	included map[uint64]bool
+	chain    blockchain.HeadFetcher
+}
+
+// NewPool accepts a head fetcher (for reading the validator set) and returns an initialized
+// voluntary exit pool.
+func NewPool(chain blockchain.HeadFetcher) *Pool {
+	return &Pool{
+		pending:  make([]*ethpb.SignedVoluntaryExit, 0),
+		included: make(map[uint64]bool),
+		chain:    chain,
+	}
+}
+
+// PendingExits returns exits that are ready for inclusion at the given slot.
+func (p *Pool) PendingExits(slot uint64) []*ethpb.SignedVoluntaryExit {
+	p.lock.RLock()
+	defer p.lock.RUnlock()
+	pending := make([]*ethpb.SignedVoluntaryExit, 0)
+	for _, e := range p.pending {
+		if e.Exit.Epoch > helpers.SlotToEpoch(slot) {
+			continue
+		}
+		pending = append(pending, e)
+	}
+	return pending
+}
+
+// InsertVoluntaryExit into the pool. This method is a no-op if the pending exit already exists,
+// has been included recently, or the validator is already exited.
+func (p *Pool) InsertVoluntaryExit(ctx context.Context, exit *ethpb.SignedVoluntaryExit) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	// Has this validator index been included recently?
+	if p.included[exit.Exit.ValidatorIndex] {
+		return
+	}
+
+	// Has the validator been exited already?
+	if h, _ := p.chain.HeadState(ctx); h == nil || len(h.Validators) <= int(exit.Exit.ValidatorIndex) || h.Validators[exit.Exit.ValidatorIndex].ExitEpoch != params.BeaconConfig().FarFutureEpoch {
+		return
+	}
+
+	// Does this validator exist in the list already? Use binary search to find the answer.
+	if found := sort.Search(len(p.pending), func(i int) bool {
+		e := p.pending[i].Exit
+		return e.ValidatorIndex == exit.Exit.ValidatorIndex
+	}); found != len(p.pending) {
+		// If an exit exists with this validator index, prefer one with an earlier exit epoch.
+		if p.pending[found].Exit.Epoch > exit.Exit.Epoch {
+			p.pending[found] = exit
+		}
+		return
+	}
+
+	// Insert into pending list and sort again.
+	p.pending = append(p.pending, exit)
+	sort.Slice(p.pending, func(i, j int) bool {
+		return p.pending[i].Exit.ValidatorIndex < p.pending[j].Exit.ValidatorIndex
+	})
+}
+
+// MarkIncluded is used when an exit has been included in a beacon block. Every block seen by this
+// node should call this method to include the exit.
+func (p *Pool) MarkIncluded(exit *ethpb.SignedVoluntaryExit) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	i := sort.Search(len(p.pending), func(i int) bool {
+		return p.pending[i].Exit.ValidatorIndex == exit.Exit.ValidatorIndex
+	})
+	if i != len(p.pending) {
+		p.pending = append(p.pending[:i], p.pending[i+1:]...)
+	}
+	p.included[exit.Exit.ValidatorIndex] = true
+}

beacon-chain/operations/voluntaryexits/service_test.go

@@ -0,0 +1,411 @@
+package voluntaryexits
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"github.com/gogo/protobuf/proto"
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+func TestPool_InsertVoluntaryExit(t *testing.T) {
+	type fields struct {
+		pending  []*ethpb.SignedVoluntaryExit
+		included map[uint64]bool
+	}
+	type args struct {
+		exit *ethpb.SignedVoluntaryExit
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   []*ethpb.SignedVoluntaryExit
+	}{
+		{
+			name: "Empty list",
+			fields: fields{
+				pending:  make([]*ethpb.SignedVoluntaryExit, 0),
+				included: make(map[uint64]bool),
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+			want: []*ethpb.SignedVoluntaryExit{
+				{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "Duplicate identical exit",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{
+						Exit: &ethpb.VoluntaryExit{
+							Epoch:          12,
+							ValidatorIndex: 1,
+						},
+					},
+				},
+				included: make(map[uint64]bool),
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+			want: []*ethpb.SignedVoluntaryExit{
+				{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "Duplicate exit with lower epoch",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{
+						Exit: &ethpb.VoluntaryExit{
+							Epoch:          12,
+							ValidatorIndex: 1,
+						},
+					},
+				},
+				included: make(map[uint64]bool),
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          10,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+			want: []*ethpb.SignedVoluntaryExit{
+				{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          10,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "Exit for already exited validator",
+			fields: fields{
+				pending:  []*ethpb.SignedVoluntaryExit{},
+				included: make(map[uint64]bool),
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 2,
+					},
+				},
+			},
+			want: []*ethpb.SignedVoluntaryExit{},
+		},
+		{
+			name: "Maintains sorted order",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{
+						Exit: &ethpb.VoluntaryExit{
+							Epoch:          12,
+							ValidatorIndex: 0,
+						},
+					},
+					{
+						Exit: &ethpb.VoluntaryExit{
+							Epoch:          12,
+							ValidatorIndex: 2,
+						},
+					},
+				},
+				included: make(map[uint64]bool),
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          10,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+			want: []*ethpb.SignedVoluntaryExit{
+				{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 0,
+					},
+				},
+				{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          10,
+						ValidatorIndex: 1,
+					},
+				},
+				{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 2,
+					},
+				},
+			},
+		},
+		{
+			name: "Already included",
+			fields: fields{
+				pending: make([]*ethpb.SignedVoluntaryExit, 0),
+				included: map[uint64]bool{
+					1: true,
+				},
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{
+						Epoch:          12,
+						ValidatorIndex: 1,
+					},
+				},
+			},
+			want: []*ethpb.SignedVoluntaryExit{},
+		},
+	}
+	ctx := context.Background()
+	chain := &mock.ChainService{
+		State: &pb.BeaconState{
+			Validators: []*ethpb.Validator{
+				{ // 0
+					ExitEpoch: params.BeaconConfig().FarFutureEpoch,
+				},
+				{ // 1
+					ExitEpoch: params.BeaconConfig().FarFutureEpoch,
+				},
+				{ // 2 - Already exited.
+					ExitEpoch: 15,
+				},
+				{ // 3
+					ExitEpoch: params.BeaconConfig().FarFutureEpoch,
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &Pool{
+				pending:  tt.fields.pending,
+				included: tt.fields.included,
+				chain:    chain,
+			}
+			p.InsertVoluntaryExit(ctx, tt.args.exit)
+			if len(p.pending) != len(tt.want) {
+				t.Fatalf("Mismatched lengths of pending list. Got %d, wanted %d.", len(p.pending), len(tt.want))
+			}
+			for i := range p.pending {
+				if !proto.Equal(p.pending[i], tt.want[i]) {
+					t.Errorf("Pending exit at index %d does not match expected. Got=%v wanted=%v", i, p.pending[i], tt.want[i])
+				}
+			}
+		})
+	}
+}
+
+func TestPool_MarkIncluded(t *testing.T) {
+	type fields struct {
+		pending  []*ethpb.SignedVoluntaryExit
+		included map[uint64]bool
+	}
+	type args struct {
+		exit *ethpb.SignedVoluntaryExit
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   fields
+	}{
+		{
+			name: "Included, does not exist in pending",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{
+						Exit: &ethpb.VoluntaryExit{ValidatorIndex: 2},
+					},
+				},
+				included: make(map[uint64]bool),
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{ValidatorIndex: 3},
+				},
+			},
+			want: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{
+						Exit: &ethpb.VoluntaryExit{ValidatorIndex: 2},
+					},
+				},
+				included: map[uint64]bool{
+					3: true,
+				},
+			},
+		},
+		{
+			name: "Removes from pending list",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{
+						Exit: &ethpb.VoluntaryExit{ValidatorIndex: 1},
+					},
+					{
+						Exit: &ethpb.VoluntaryExit{ValidatorIndex: 2},
+					},
+					{
+						Exit: &ethpb.VoluntaryExit{ValidatorIndex: 3},
+					},
+				},
+				included: map[uint64]bool{
+					0: true,
+				},
+			},
+			args: args{
+				exit: &ethpb.SignedVoluntaryExit{
+					Exit: &ethpb.VoluntaryExit{ValidatorIndex: 2},
+				},
+			},
+			want: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{
+						Exit: &ethpb.VoluntaryExit{ValidatorIndex: 1},
+					},
+					{
+						Exit: &ethpb.VoluntaryExit{ValidatorIndex: 3},
+					},
+				},
+				included: map[uint64]bool{
+					0: true,
+					2: true,
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &Pool{
+				pending:  tt.fields.pending,
+				included: tt.fields.included,
+			}
+			p.MarkIncluded(tt.args.exit)
+			if len(p.pending) != len(tt.want.pending) {
+				t.Fatalf("Mismatched lengths of pending list. Got %d, wanted %d.", len(p.pending), len(tt.want.pending))
+			}
+			for i := range p.pending {
+				if !proto.Equal(p.pending[i], tt.want.pending[i]) {
+					t.Errorf("Pending exit at index %d does not match expected. Got=%v wanted=%v", i, p.pending[i], tt.want.pending[i])
+				}
+			}
+			if !reflect.DeepEqual(p.included, tt.want.included) {
+				t.Errorf("Included map is not as expected. Got=%v wanted=%v", p.included, tt.want.included)
+			}
+		})
+	}
+}
+
+func TestPool_PendingExits(t *testing.T) {
+	type fields struct {
+		pending []*ethpb.SignedVoluntaryExit
+	}
+	type args struct {
+		slot uint64
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   []*ethpb.SignedVoluntaryExit
+	}{
+		{
+			name: "Empty list",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{},
+			},
+			args: args{
+				slot: 100000,
+			},
+			want: []*ethpb.SignedVoluntaryExit{},
+		},
+		{
+			name: "All eligible",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{Exit: &ethpb.VoluntaryExit{Epoch: 0}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 1}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 2}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 3}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 4}},
+				},
+			},
+			args: args{
+				slot: 1000000,
+			},
+			want: []*ethpb.SignedVoluntaryExit{
+				{Exit: &ethpb.VoluntaryExit{Epoch: 0}},
+				{Exit: &ethpb.VoluntaryExit{Epoch: 1}},
+				{Exit: &ethpb.VoluntaryExit{Epoch: 2}},
+				{Exit: &ethpb.VoluntaryExit{Epoch: 3}},
+				{Exit: &ethpb.VoluntaryExit{Epoch: 4}},
+			},
+		},
+		{
+			name: "Some eligible",
+			fields: fields{
+				pending: []*ethpb.SignedVoluntaryExit{
+					{Exit: &ethpb.VoluntaryExit{Epoch: 0}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 3}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 4}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 2}},
+					{Exit: &ethpb.VoluntaryExit{Epoch: 1}},
+				},
+			},
+			args: args{
+				slot: 2 * params.BeaconConfig().SlotsPerEpoch,
+			},
+			want: []*ethpb.SignedVoluntaryExit{
+				{Exit: &ethpb.VoluntaryExit{Epoch: 0}},
+				{Exit: &ethpb.VoluntaryExit{Epoch: 2}},
+				{Exit: &ethpb.VoluntaryExit{Epoch: 1}},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &Pool{
+				pending: tt.fields.pending,
+			}
+			if got := p.PendingExits(tt.args.slot); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("PendingExits() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}