Add block analyze.

2026-01-08 21:48:05 -05:00 · 2022-03-06 22:47:37 +00:00
parent 3b51c67e7d
commit 3d49e091e5
11 changed files with 1012 additions and 3 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 dev:
  - add "-ssz" option to "block info"
+  - add "block analyze" command

 1.17.0:
  - add sync committee information to "chain time"
--- a/cmd/block/analyze/command.go
+++ b/cmd/block/analyze/command.go
@@ -0,0 +1,136 @@
+// Copyright © 2022 Weald Technology Trading.
+// 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 blockanalyze
+
+import (
+	"context"
+	"time"
+
+	eth2client "github.com/attestantio/go-eth2-client"
+	"github.com/attestantio/go-eth2-client/spec/phase0"
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/spf13/viper"
+	"github.com/wealdtech/ethdo/services/chaintime"
+)
+
+type command struct {
+	quiet   bool
+	verbose bool
+	debug   bool
+
+	// Beacon node connection.
+	timeout                  time.Duration
+	connection               string
+	allowInsecureConnections bool
+
+	// Operation.
+	blockID    string
+	stream     bool
+	jsonOutput bool
+
+	// Data access.
+	eth2Client           eth2client.Service
+	chainTime            chaintime.Service
+	blocksProvider       eth2client.SignedBeaconBlockProvider
+	blockHeadersProvider eth2client.BeaconBlockHeadersProvider
+
+	// Constants.
+	timelySourceWeight uint64
+	timelyTargetWeight uint64
+	timelyHeadWeight   uint64
+	syncRewardWeight   uint64
+	proposerWeight     uint64
+	weightDenominator  uint64
+
+	// Processing.
+	priorAttestations map[string]*attestationData
+	// Head roots provides the root of the head slot at given slots.
+	headRoots map[phase0.Slot]phase0.Root
+	// Target roots provides the root of the target epoch at given slots.
+	targetRoots map[phase0.Slot]phase0.Root
+
+	// Block info.
+	// Map is slot -> committee index -> validator committee index -> votes.
+	votes map[phase0.Slot]map[phase0.CommitteeIndex]bitfield.Bitlist
+
+	// Results.
+	analysis *blockAnalysis
+}
+
+type blockAnalysis struct {
+	Slot         phase0.Slot            `json:"slot"`
+	Attestations []*attestationAnalysis `json:"attestations"`
+	SyncCommitee *syncCommitteeAnalysis `json:"sync_committee"`
+	Value        float64                `json:"value"`
+}
+
+type attestationAnalysis struct {
+	Head          phase0.Root      `json:"head"`
+	Target        phase0.Root      `json:"target"`
+	Distance      int              `json:"distance"`
+	Duplicate     *attestationData `json:"duplicate,omitempty"`
+	NewVotes      int              `json:"new_votes"`
+	Votes         int              `json:"votes"`
+	PossibleVotes int              `json:"possible_votes"`
+	HeadCorrect   bool             `json:"head_correct"`
+	HeadTimely    bool             `json:"head_timely"`
+	SourceTimely  bool             `json:"source_timely"`
+	TargetCorrect bool             `json:"target_correct"`
+	TargetTimely  bool             `json:"target_timely"`
+	Score         float64          `json:"score"`
+	Value         float64          `json:"value"`
+}
+
+type syncCommitteeAnalysis struct {
+	Contributions         int     `json:"contributions"`
+	PossibleContributions int     `json:"possible_contributions"`
+	Score                 float64 `json:"score"`
+	Value                 float64 `json:"value"`
+}
+
+type attestationData struct {
+	Block phase0.Slot `json:"block"`
+	Index int         `json:"index"`
+}
+
+func newCommand(ctx context.Context) (*command, error) {
+	c := &command{
+		quiet:             viper.GetBool("quiet"),
+		verbose:           viper.GetBool("verbose"),
+		debug:             viper.GetBool("debug"),
+		priorAttestations: make(map[string]*attestationData),
+		headRoots:         make(map[phase0.Slot]phase0.Root),
+		targetRoots:       make(map[phase0.Slot]phase0.Root),
+		votes:             make(map[phase0.Slot]map[phase0.CommitteeIndex]bitfield.Bitlist),
+	}
+
+	// Timeout.
+	if viper.GetDuration("timeout") == 0 {
+		return nil, errors.New("timeout is required")
+	}
+	c.timeout = viper.GetDuration("timeout")
+
+	if viper.GetString("connection") == "" {
+		return nil, errors.New("connection is required")
+	}
+	c.connection = viper.GetString("connection")
+	c.allowInsecureConnections = viper.GetBool("allow-insecure-connections")
+
+	c.blockID = viper.GetString("blockid")
+	c.stream = viper.GetBool("stream")
+	c.jsonOutput = viper.GetBool("json")
+
+	return c, nil
+}
--- a/cmd/block/analyze/command_internal_test.go
+++ b/cmd/block/analyze/command_internal_test.go
@@ -0,0 +1,82 @@
+// Copyright © 2022 Weald Technology Trading.
+// 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 blockanalyze
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInput(t *testing.T) {
+	if os.Getenv("ETHDO_TEST_CONNECTION") == "" {
+		t.Skip("ETHDO_TEST_CONNECTION not configured; cannot run tests")
+	}
+
+	tests := []struct {
+		name string
+		vars map[string]interface{}
+		err  string
+	}{
+		{
+			name: "TimeoutMissing",
+			vars: map[string]interface{}{},
+			err:  "timeout is required",
+		},
+		{
+			name: "ConnectionMissing",
+			vars: map[string]interface{}{
+				"validators": "1",
+				"timeout":    "5s",
+			},
+			err: "connection is required",
+		},
+		{
+			name: "ValidatorsZero",
+			vars: map[string]interface{}{
+				"timeout":    "5s",
+				"validators": "0",
+				"connection": os.Getenv("ETHDO_TEST_CONNECTION"),
+			},
+			err: "validators must be at least 1",
+		},
+		{
+			name: "Good",
+			vars: map[string]interface{}{
+				"validators": "1",
+				"timeout":    "5s",
+				"connection": os.Getenv("ETHDO_TEST_CONNECTION"),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			viper.Reset()
+
+			for k, v := range test.vars {
+				viper.Set(k, v)
+			}
+			_, err := newCommand(context.Background())
+			if test.err != "" {
+				require.EqualError(t, err, test.err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
--- a/cmd/block/analyze/output.go
+++ b/cmd/block/analyze/output.go
@@ -0,0 +1,157 @@
+// Copyright © 2022 Weald Technology Trading.
+// 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 blockanalyze
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+func (c *command) output(ctx context.Context) (string, error) {
+	if c.quiet {
+		return "", nil
+	}
+
+	if c.jsonOutput {
+		return c.outputJSON(ctx)
+	}
+
+	return c.outputTxt(ctx)
+}
+
+type attestationAnalysisJSON struct {
+	Head          string           `json:"head"`
+	Target        string           `json:"target"`
+	Distance      int              `json:"distance"`
+	Duplicate     *attestationData `json:"duplicate,omitempty"`
+	NewVotes      int              `json:"new_votes"`
+	Votes         int              `json:"votes"`
+	PossibleVotes int              `json:"possible_votes"`
+	HeadCorrect   bool             `json:"head_correct"`
+	HeadTimely    bool             `json:"head_timely"`
+	SourceTimely  bool             `json:"source_timely"`
+	TargetCorrect bool             `json:"target_correct"`
+	TargetTimely  bool             `json:"target_timely"`
+	Score         float64          `json:"score"`
+	Value         float64          `json:"value"`
+}
+
+func (a *attestationAnalysis) MarshalJSON() ([]byte, error) {
+	return json.Marshal(attestationAnalysisJSON{
+		Head:          fmt.Sprintf("%#x", a.Head),
+		Target:        fmt.Sprintf("%#x", a.Target),
+		Distance:      a.Distance,
+		Duplicate:     a.Duplicate,
+		NewVotes:      a.NewVotes,
+		Votes:         a.Votes,
+		PossibleVotes: a.PossibleVotes,
+		HeadCorrect:   a.HeadCorrect,
+		HeadTimely:    a.HeadTimely,
+		SourceTimely:  a.SourceTimely,
+		TargetCorrect: a.TargetCorrect,
+		TargetTimely:  a.TargetTimely,
+		Score:         a.Score,
+		Value:         a.Value,
+	})
+}
+
+func (c *command) outputJSON(_ context.Context) (string, error) {
+	data, err := json.Marshal(c.analysis)
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}
+
+func (c *command) outputTxt(_ context.Context) (string, error) {
+	builder := strings.Builder{}
+
+	for i, attestation := range c.analysis.Attestations {
+		if c.verbose {
+			builder.WriteString("Attestation ")
+			builder.WriteString(fmt.Sprintf("%d", i))
+			builder.WriteString(": ")
+			builder.WriteString("distance ")
+			builder.WriteString(fmt.Sprintf("%d", attestation.Distance))
+			builder.WriteString(", ")
+
+			if attestation.Duplicate != nil {
+				builder.WriteString("duplicate of attestation ")
+				builder.WriteString(fmt.Sprintf("%d", attestation.Duplicate.Index))
+				builder.WriteString(" in block ")
+				builder.WriteString(fmt.Sprintf("%d", attestation.Duplicate.Block))
+				builder.WriteString("\n")
+				continue
+			}
+
+			builder.WriteString(fmt.Sprintf("%d", attestation.NewVotes))
+			builder.WriteString("/")
+			builder.WriteString(fmt.Sprintf("%d", attestation.Votes))
+			builder.WriteString("/")
+			builder.WriteString(fmt.Sprintf("%d", attestation.PossibleVotes))
+			builder.WriteString(" new/total/possible votes")
+			if attestation.NewVotes == 0 {
+				builder.WriteString("\n")
+				continue
+			} else {
+				builder.WriteString(", ")
+			}
+			switch {
+			case !attestation.HeadCorrect:
+				builder.WriteString("head vote incorrect, ")
+			case !attestation.HeadTimely:
+				builder.WriteString("head vote correct but late, ")
+			}
+
+			if !attestation.SourceTimely {
+				builder.WriteString("source vote late, ")
+			}
+
+			switch {
+			case !attestation.TargetCorrect:
+				builder.WriteString("target vote incorrect, ")
+			case !attestation.TargetTimely:
+				builder.WriteString("target vote correct but late, ")
+			}
+
+			builder.WriteString("score ")
+			builder.WriteString(fmt.Sprintf("%0.3f", attestation.Score))
+			builder.WriteString(", value ")
+			builder.WriteString(fmt.Sprintf("%0.3f", attestation.Value))
+			builder.WriteString("\n")
+		}
+	}
+
+	if c.analysis.SyncCommitee.Contributions > 0 {
+		if c.verbose {
+			builder.WriteString("Sync committee contributions: ")
+			builder.WriteString(fmt.Sprintf("%d", c.analysis.SyncCommitee.Contributions))
+			builder.WriteString(" contributions, score ")
+			builder.WriteString(fmt.Sprintf("%0.3f", c.analysis.SyncCommitee.Score))
+			builder.WriteString(", value ")
+			builder.WriteString(fmt.Sprintf("%0.3f", c.analysis.SyncCommitee.Value))
+			builder.WriteString("\n")
+		}
+	}
+
+	builder.WriteString("Value for block ")
+	builder.WriteString(fmt.Sprintf("%d", c.analysis.Slot))
+	builder.WriteString(": ")
+	builder.WriteString(fmt.Sprintf("%0.3f", c.analysis.Value))
+	builder.WriteString("\n")
+
+	return builder.String(), nil
+}
--- a/cmd/block/analyze/process.go
+++ b/cmd/block/analyze/process.go
@@ -0,0 +1,431 @@
+// Copyright © 2022 Weald Technology Trading.
+// 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 blockanalyze
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+
+	eth2client "github.com/attestantio/go-eth2-client"
+	"github.com/attestantio/go-eth2-client/spec"
+	"github.com/attestantio/go-eth2-client/spec/phase0"
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/go-bitfield"
+	standardchaintime "github.com/wealdtech/ethdo/services/chaintime/standard"
+	"github.com/wealdtech/ethdo/util"
+)
+
+func (c *command) process(ctx context.Context) error {
+	// Obtain information we need to process.
+	if err := c.setup(ctx); err != nil {
+		return err
+	}
+
+	block, err := c.blocksProvider.SignedBeaconBlock(ctx, c.blockID)
+	if err != nil {
+		return errors.Wrap(err, "failed to obtain beacon block")
+	}
+	if block == nil {
+		return errors.New("empty beacon block")
+	}
+
+	slot, err := block.Slot()
+	if err != nil {
+		return err
+	}
+	attestations, err := block.Attestations()
+	if err != nil {
+		return err
+	}
+
+	c.analysis = &blockAnalysis{
+		Slot: slot,
+	}
+
+	// Calculate how many parents we need to fetch.
+	minSlot := slot
+	for _, attestation := range attestations {
+		if attestation.Data.Slot < minSlot {
+			minSlot = attestation.Data.Slot
+		}
+	}
+	if c.debug {
+		fmt.Printf("Need to fetch blocks to slot %d\n", minSlot)
+	}
+
+	if err := c.fetchParents(ctx, block, minSlot); err != nil {
+		return err
+	}
+
+	return c.analyze(ctx, block)
+}
+
+func (c *command) analyze(ctx context.Context, block *spec.VersionedSignedBeaconBlock) error {
+	if err := c.analyzeAttestations(ctx, block); err != nil {
+		return err
+	}
+
+	if err := c.analyzeSyncCommittees(ctx, block); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *command) analyzeAttestations(ctx context.Context, block *spec.VersionedSignedBeaconBlock) error {
+	attestations, err := block.Attestations()
+	if err != nil {
+		return err
+	}
+	slot, err := block.Slot()
+	if err != nil {
+		return err
+	}
+
+	c.analysis.Attestations = make([]*attestationAnalysis, len(attestations))
+
+	blockVotes := make(map[phase0.Slot]map[phase0.CommitteeIndex]bitfield.Bitlist)
+	for i, attestation := range attestations {
+		if c.debug {
+			fmt.Printf("Processing attestation %d\n", i)
+		}
+		analysis := &attestationAnalysis{
+			Head:     attestation.Data.BeaconBlockRoot,
+			Target:   attestation.Data.Target.Root,
+			Distance: int(slot - attestation.Data.Slot),
+		}
+
+		root, err := attestation.HashTreeRoot()
+		if err != nil {
+			return err
+		}
+		if info, exists := c.priorAttestations[fmt.Sprintf("%#x", root)]; exists {
+			analysis.Duplicate = info
+		} else {
+			data := attestation.Data
+			_, exists := blockVotes[data.Slot]
+			if !exists {
+				blockVotes[data.Slot] = make(map[phase0.CommitteeIndex]bitfield.Bitlist)
+			}
+			_, exists = blockVotes[data.Slot][data.Index]
+			if !exists {
+				blockVotes[data.Slot][data.Index] = bitfield.NewBitlist(attestation.AggregationBits.Len())
+			}
+
+			// Count new votes.
+			analysis.PossibleVotes = int(attestation.AggregationBits.Len())
+			for j := uint64(0); j < attestation.AggregationBits.Len(); j++ {
+				if attestation.AggregationBits.BitAt(j) {
+					analysis.Votes++
+					if blockVotes[data.Slot][data.Index].BitAt(j) {
+						// Already attested to in this block; skip.
+						continue
+					}
+					if c.votes[data.Slot][data.Index].BitAt(j) {
+						// Already attested to in a previous block; skip.
+						continue
+					}
+					analysis.NewVotes++
+					blockVotes[data.Slot][data.Index].SetBitAt(j, true)
+				}
+			}
+			// Calculate head correct.
+			var err error
+			analysis.HeadCorrect, err = c.calcHeadCorrect(ctx, attestation)
+			if err != nil {
+				return err
+			}
+
+			// Calculate head timely.
+			analysis.HeadTimely = attestation.Data.Slot == slot-1
+
+			// Calculate source timely.
+			analysis.SourceTimely = attestation.Data.Slot >= slot-5
+
+			// Calculate target correct.
+			analysis.TargetCorrect, err = c.calcTargetCorrect(ctx, attestation)
+			if err != nil {
+				return err
+			}
+
+			// Calculate target timely.
+			analysis.TargetTimely = attestation.Data.Slot >= slot-32
+		}
+
+		// Calculate score and value.
+		if analysis.TargetCorrect && analysis.TargetTimely {
+			analysis.Score += float64(c.timelyTargetWeight) / float64(c.weightDenominator)
+		}
+		if analysis.SourceTimely {
+			analysis.Score += float64(c.timelySourceWeight) / float64(c.weightDenominator)
+		}
+		if analysis.HeadCorrect && analysis.HeadTimely {
+			analysis.Score += float64(c.timelyHeadWeight) / float64(c.weightDenominator)
+		}
+		analysis.Value = analysis.Score * float64(analysis.NewVotes)
+		c.analysis.Value += analysis.Value
+
+		c.analysis.Attestations[i] = analysis
+	}
+
+	return nil
+}
+
+func (c *command) fetchParents(ctx context.Context, block *spec.VersionedSignedBeaconBlock, minSlot phase0.Slot) error {
+	parentRoot, err := block.ParentRoot()
+	if err != nil {
+		return err
+	}
+
+	// Obtain the parent block.
+	parentBlock, err := c.blocksProvider.SignedBeaconBlock(ctx, fmt.Sprintf("%#x", parentRoot))
+	if err != nil {
+		return err
+	}
+	if parentBlock == nil {
+		return fmt.Errorf("unable to obtain parent block %s", parentBlock)
+	}
+
+	parentSlot, err := parentBlock.Slot()
+	if err != nil {
+		return err
+	}
+	if parentSlot < minSlot {
+		return nil
+	}
+
+	if err := c.processParentBlock(ctx, parentBlock); err != nil {
+		return err
+	}
+
+	return c.fetchParents(ctx, parentBlock, minSlot)
+}
+
+func (c *command) processParentBlock(ctx context.Context, block *spec.VersionedSignedBeaconBlock) error {
+	attestations, err := block.Attestations()
+	if err != nil {
+		return err
+	}
+	slot, err := block.Slot()
+	if err != nil {
+		return err
+	}
+	if c.debug {
+		fmt.Printf("Processing block %d\n", slot)
+	}
+
+	for i, attestation := range attestations {
+		root, err := attestation.HashTreeRoot()
+		if err != nil {
+			return err
+		}
+		c.priorAttestations[fmt.Sprintf("%#x", root)] = &attestationData{
+			Block: slot,
+			Index: i,
+		}
+
+		data := attestation.Data
+		_, exists := c.votes[data.Slot]
+		if !exists {
+			c.votes[data.Slot] = make(map[phase0.CommitteeIndex]bitfield.Bitlist)
+		}
+		_, exists = c.votes[data.Slot][data.Index]
+		if !exists {
+			c.votes[data.Slot][data.Index] = bitfield.NewBitlist(attestation.AggregationBits.Len())
+		}
+		for j := uint64(0); j < attestation.AggregationBits.Len(); j++ {
+			if attestation.AggregationBits.BitAt(j) {
+				c.votes[data.Slot][data.Index].SetBitAt(j, true)
+			}
+		}
+	}
+
+	return nil
+}
+
+func (c *command) setup(ctx context.Context) error {
+	var err error
+
+	// Connect to the client.
+	c.eth2Client, err = util.ConnectToBeaconNode(ctx, c.connection, c.timeout, c.allowInsecureConnections)
+	if err != nil {
+		return errors.Wrap(err, "failed to connect to beacon node")
+	}
+
+	c.chainTime, err = standardchaintime.New(ctx,
+		standardchaintime.WithSpecProvider(c.eth2Client.(eth2client.SpecProvider)),
+		standardchaintime.WithForkScheduleProvider(c.eth2Client.(eth2client.ForkScheduleProvider)),
+		standardchaintime.WithGenesisTimeProvider(c.eth2Client.(eth2client.GenesisTimeProvider)),
+	)
+	if err != nil {
+		return errors.Wrap(err, "failed to set up chaintime service")
+	}
+
+	// Obtain the number of active validators.
+	var isProvider bool
+	c.blocksProvider, isProvider = c.eth2Client.(eth2client.SignedBeaconBlockProvider)
+	if !isProvider {
+		return errors.New("connection does not provide signed beacon block information")
+	}
+	c.blockHeadersProvider, isProvider = c.eth2Client.(eth2client.BeaconBlockHeadersProvider)
+	if !isProvider {
+		return errors.New("connection does not provide beacon block header information")
+	}
+
+	specProvider, isProvider := c.eth2Client.(eth2client.SpecProvider)
+	if !isProvider {
+		return errors.New("connection does not provide spec information")
+	}
+
+	spec, err := specProvider.Spec(ctx)
+	if err != nil {
+		return errors.Wrap(err, "failed to obtain spec")
+	}
+
+	tmp, exists := spec["TIMELY_SOURCE_WEIGHT"]
+	if !exists {
+		// Set a default value based on the Altair spec.
+		tmp = uint64(14)
+	}
+	var ok bool
+	c.timelySourceWeight, ok = tmp.(uint64)
+	if !ok {
+		return errors.New("TIMELY_SOURCE_WEIGHT of unexpected type")
+	}
+
+	tmp, exists = spec["TIMELY_TARGET_WEIGHT"]
+	if !exists {
+		// Set a default value based on the Altair spec.
+		tmp = uint64(26)
+	}
+	c.timelyTargetWeight, ok = tmp.(uint64)
+	if !ok {
+		return errors.New("TIMELY_TARGET_WEIGHT of unexpected type")
+	}
+
+	tmp, exists = spec["TIMELY_HEAD_WEIGHT"]
+	if !exists {
+		// Set a default value based on the Altair spec.
+		tmp = uint64(14)
+	}
+	c.timelyHeadWeight, ok = tmp.(uint64)
+	if !ok {
+		return errors.New("TIMELY_HEAD_WEIGHT of unexpected type")
+	}
+
+	tmp, exists = spec["SYNC_REWARD_WEIGHT"]
+	if !exists {
+		// Set a default value based on the Altair spec.
+		tmp = uint64(2)
+	}
+	c.syncRewardWeight, ok = tmp.(uint64)
+	if !ok {
+		return errors.New("SYNC_REWARD_WEIGHT of unexpected type")
+	}
+
+	tmp, exists = spec["PROPOSER_WEIGHT"]
+	if !exists {
+		// Set a default value based on the Altair spec.
+		tmp = uint64(8)
+	}
+	c.proposerWeight, ok = tmp.(uint64)
+	if !ok {
+		return errors.New("PROPOSER_WEIGHT of unexpected type")
+	}
+
+	tmp, exists = spec["WEIGHT_DENOMINATOR"]
+	if !exists {
+		// Set a default value based on the Altair spec.
+		tmp = uint64(64)
+	}
+	c.weightDenominator, ok = tmp.(uint64)
+	if !ok {
+		return errors.New("WEIGHT_DENOMINATOR of unexpected type")
+	}
+	return nil
+}
+
+func (c *command) calcHeadCorrect(ctx context.Context, attestation *phase0.Attestation) (bool, error) {
+	slot := attestation.Data.Slot
+	root, exists := c.headRoots[slot]
+	if !exists {
+		for {
+			header, err := c.blockHeadersProvider.BeaconBlockHeader(ctx, fmt.Sprintf("%d", slot))
+			if err != nil {
+				return false, nil
+			}
+			if header == nil {
+				// No block.
+				slot--
+				continue
+			}
+			if !header.Canonical {
+				// Not canonical.
+				slot--
+				continue
+			}
+			c.headRoots[attestation.Data.Slot] = header.Root
+			root = header.Root
+			break
+		}
+	}
+
+	return bytes.Equal(root[:], attestation.Data.BeaconBlockRoot[:]), nil
+}
+
+func (c *command) calcTargetCorrect(ctx context.Context, attestation *phase0.Attestation) (bool, error) {
+	root, exists := c.targetRoots[attestation.Data.Slot]
+	if !exists {
+		// Start with first slot of the target epoch.
+		slot := c.chainTime.FirstSlotOfEpoch(attestation.Data.Target.Epoch)
+		for {
+			header, err := c.blockHeadersProvider.BeaconBlockHeader(ctx, fmt.Sprintf("%d", slot))
+			if err != nil {
+				return false, nil
+			}
+			if header == nil {
+				// No block.
+				slot--
+				continue
+			}
+			if !header.Canonical {
+				// Not canonical.
+				slot--
+				continue
+			}
+			c.targetRoots[attestation.Data.Slot] = header.Root
+			root = header.Root
+			break
+		}
+	}
+	return bytes.Equal(root[:], attestation.Data.Target.Root[:]), nil
+}
+
+func (c *command) analyzeSyncCommittees(ctx context.Context, block *spec.VersionedSignedBeaconBlock) error {
+	c.analysis.SyncCommitee = &syncCommitteeAnalysis{}
+	switch block.Version {
+	case spec.DataVersionPhase0:
+		return nil
+	case spec.DataVersionAltair:
+		c.analysis.SyncCommitee.Contributions = int(block.Altair.Message.Body.SyncAggregate.SyncCommitteeBits.Count())
+		c.analysis.SyncCommitee.PossibleContributions = int(block.Altair.Message.Body.SyncAggregate.SyncCommitteeBits.Len())
+		c.analysis.SyncCommitee.Score = float64(c.syncRewardWeight) / float64(c.weightDenominator)
+		c.analysis.SyncCommitee.Value = c.analysis.SyncCommitee.Score * float64(c.analysis.SyncCommitee.Contributions)
+		c.analysis.Value += c.analysis.SyncCommitee.Value
+		return nil
+	default:
+		return fmt.Errorf("unsupported block version %d", block.Version)
+	}
+}
--- a/cmd/block/analyze/process_internal_test.go
+++ b/cmd/block/analyze/process_internal_test.go
@@ -0,0 +1,63 @@
+// Copyright © 2022 Weald Technology Trading.
+// 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 blockanalyze
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/require"
+)
+
+func TestProcess(t *testing.T) {
+	if os.Getenv("ETHDO_TEST_CONNECTION") == "" {
+		t.Skip("ETHDO_TEST_CONNECTION not configured; cannot run tests")
+	}
+
+	tests := []struct {
+		name string
+		vars map[string]interface{}
+		err  string
+	}{
+		{
+			name: "InvalidData",
+			vars: map[string]interface{}{
+				"timeout":    "60s",
+				"validators": "1",
+				"data":       "[[",
+				"connection": os.Getenv("ETHDO_TEST_CONNECTION"),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			viper.Reset()
+
+			for k, v := range test.vars {
+				viper.Set(k, v)
+			}
+			cmd, err := newCommand(context.Background())
+			require.NoError(t, err)
+			err = cmd.process(context.Background())
+			if test.err != "" {
+				require.EqualError(t, err, test.err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
--- a/cmd/block/analyze/run.go
+++ b/cmd/block/analyze/run.go
@@ -0,0 +1,50 @@
+// Copyright © 2022 Weald Technology Trading.
+// 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 blockanalyze
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+// Run runs the command.
+func Run(cmd *cobra.Command) (string, error) {
+	ctx := context.Background()
+
+	c, err := newCommand(ctx)
+	if err != nil {
+		return "", errors.Wrap(err, "failed to set up command")
+	}
+
+	// Further errors do not need a usage report.
+	cmd.SilenceUsage = true
+
+	if err := c.process(ctx); err != nil {
+		return "", errors.Wrap(err, "failed to process")
+	}
+
+	if viper.GetBool("quiet") {
+		return "", nil
+	}
+
+	results, err := c.output(ctx)
+	if err != nil {
+		return "", errors.Wrap(err, "failed to obtain output")
+	}
+
+	return results, nil
+}
--- a/cmd/blockanalyze.go
+++ b/cmd/blockanalyze.go
@@ -0,0 +1,65 @@
+// Copyright © 2022 Weald Technology Trading
+// 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 cmd
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	blockanalyze "github.com/wealdtech/ethdo/cmd/block/analyze"
+)
+
+var blockAnalyzeCmd = &cobra.Command{
+	Use:   "analyze",
+	Short: "Analyze a block",
+	Long: `Analyze the contents of a block.  For example:
+
+    ethdo block analyze --blockid=12345
+
+In quiet mode this will return 0 if the block information is present and not skipped, otherwise 1.`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		res, err := blockanalyze.Run(cmd)
+		if err != nil {
+			return err
+		}
+		if viper.GetBool("quiet") {
+			return nil
+		}
+		if res != "" {
+			fmt.Print(res)
+		}
+		return nil
+	},
+}
+
+func init() {
+	blockCmd.AddCommand(blockAnalyzeCmd)
+	blockFlags(blockAnalyzeCmd)
+	blockAnalyzeCmd.Flags().String("blockid", "head", "the ID of the block to fetch")
+	blockAnalyzeCmd.Flags().Bool("stream", false, "continually stream blocks as they arrive")
+	blockAnalyzeCmd.Flags().Bool("json", false, "output data in JSON format")
+}
+
+func blockAnalyzeBindings() {
+	if err := viper.BindPFlag("blockid", blockAnalyzeCmd.Flags().Lookup("blockid")); err != nil {
+		panic(err)
+	}
+	if err := viper.BindPFlag("stream", blockAnalyzeCmd.Flags().Lookup("stream")); err != nil {
+		panic(err)
+	}
+	if err := viper.BindPFlag("json", blockAnalyzeCmd.Flags().Lookup("json")); err != nil {
+		panic(err)
+	}
+}
--- a/cmd/blockinfo.go
+++ b/cmd/blockinfo.go
@@ -26,7 +26,7 @@ var blockInfoCmd = &cobra.Command{
 	Short: "Obtain information about a block",
 	Long: `Obtain information about a block.  For example:

-    ethdo block info --slot=12345
+    ethdo block info --blockid=12345

 In quiet mode this will return 0 if the block information is present and not skipped, otherwise 1.`,
 	RunE: func(cmd *cobra.Command, args []string) error {
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -89,6 +89,8 @@ func includeCommandBindings(cmd *cobra.Command) {
 		attesterDutiesBindings()
 	case "attester/inclusion":
 		attesterInclusionBindings()
+	case "block/analyze":
+		blockAnalyzeBindings()
 	case "block/info":
 		blockInfoBindings()
 	case "chain/time":
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -266,13 +266,35 @@ $ ethdo version
 ### `block` commands

 Block commands focus on providing information about Ethereum 2 blocks.
+#### `analyze`
+`ethdo block info` obtains information about a block in Ethereum 2.  Options include:
+  - `blockid`: the ID (slot, root, 'head') of the block to obtain
+
+```sh
+$ ethdo block analyze --blockid=80
+Value for block 80: 488.531
+```
+
+Additional information is supplied when using `--verbose`
+
+```
+$ ethdo block analyze --blockid=80 --verbose
+Attestation 0: distance 1, 119/119/132 new/total/possible votes, score 0.844, value 100.406
+Attestation 1: distance 1, 116/116/131 new/total/possible votes, score 0.844, value 97.875
+Attestation 2: distance 1, 115/115/131 new/total/possible votes, score 0.844, value 97.031
+Attestation 3: distance 1, 114/114/132 new/total/possible votes, score 0.844, value 96.188
+Attestation 4: distance 1, 113/113/132 new/total/possible votes, score 0.844, value 95.344
+Attestation 5: distance 1, 2/22/132 new/total/possible votes, score 0.844, value 1.688
+Value for block 80: 488.531
+```
+
 #### `info`

 `ethdo block info` obtains information about a block in Ethereum 2.  Options include:
-  - `slot`: the slot at which to attempt to fetch the block
+  - `blockid`: the ID (slot, root, 'head') of the block to obtain

 ```sh
-$ ethdo block info --slot=80 
+$ ethdo block info --blockid=80
 Attestations: 1
 Attester slashings: 0
 Deposits: 0