chore(structure): Allow lazy-loading of downstream clients

pkg/exporter/consensus/consensus.go

@@ -13,6 +13,8 @@ import (
 type Node interface {
 	Name() string
 	URL() string
+	Bootstrapped() bool
+	Bootstrap(ctx context.Context) error
 	SyncStatus(ctx context.Context) (*SyncStatus, error)
 }
 
@@ -25,18 +27,9 @@ type node struct {
 }
 
 func NewConsensusNode(ctx context.Context, log logrus.FieldLogger, name string, url string, metrics Metrics) (*node, error) {
-	client, err := http.New(ctx,
-		http.WithAddress(url),
-		http.WithLogLevel(zerolog.WarnLevel),
-	)
-	if err != nil {
-		log.WithError(err).Error("Failed to create consensus client")
-	}
-
 	return &node{
 		name:    name,
 		url:     url,
-		client:  client,
 		log:     log,
 		metrics: metrics,
 	}, nil
@@ -50,6 +43,29 @@ func (c *node) URL() string {
 	return c.url
 }
 
+func (c *node) Bootstrap(ctx context.Context) error {
+	client, err := http.New(ctx,
+		http.WithAddress(c.url),
+		http.WithLogLevel(zerolog.WarnLevel),
+	)
+	if err != nil {
+		return err
+	}
+
+	c.client = client
+
+	return nil
+}
+
+func (c *node) Bootstrapped() bool {
+	_, isProvider := c.client.(eth2client.NodeSyncingProvider)
+	if !isProvider {
+		return false
+	}
+
+	return true
+}
+
 func (c *node) refreshClient(ctx context.Context) error {
 	client, err := http.New(ctx,
 		http.WithAddress(c.url),

pkg/exporter/ethereum.go

@@ -45,6 +45,8 @@ func (e *ethereum) Init(ctx context.Context) error {
 			return err
 		}
 
+		consensus.Bootstrap(ctx)
+
 		e.consensus = consensus
 	}
 
@@ -54,6 +56,8 @@ func (e *ethereum) Init(ctx context.Context) error {
 			return err
 		}
 
+		execution.Bootstrap(ctx)
+
 		e.execution = execution
 	}
 
@@ -84,11 +88,52 @@ func (e *ethereum) Serve(ctx context.Context, port int) error {
 }
 
 func (e *ethereum) Tick(ctx context.Context) {
-	if _, err := e.GetSyncStatus(ctx); err != nil {
+	if err := e.PollConsensus(ctx); err != nil {
+		e.log.Error(err)
+	}
+	if err := e.PollExecution(ctx); err != nil {
 		e.log.Error(err)
 	}
 }
 
+func (e *ethereum) PollConsensus(ctx context.Context) error {
+	if !e.config.Consensus.Enabled {
+		return nil
+	}
+
+	if !e.consensus.Bootstrapped() {
+		if err := e.consensus.Bootstrap(ctx); err != nil {
+			return err
+		}
+	}
+
+	// TODO(sam.calder-mason): Parallelize this
+	if _, err := e.consensus.SyncStatus(ctx); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (e *ethereum) PollExecution(ctx context.Context) error {
+	if !e.config.Execution.Enabled {
+		return nil
+	}
+
+	if !e.execution.Bootstrapped() {
+		if err := e.execution.Bootstrap(ctx); err != nil {
+			return err
+		}
+	}
+
+	// TODO(sam.calder-mason): Parallelize this
+	if _, err := e.execution.SyncStatus(ctx); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func (e *ethereum) GetSyncStatus(ctx context.Context) (*SyncStatus, error) {
 	status := &SyncStatus{}
 	consensus, err := e.consensus.SyncStatus(ctx)

pkg/exporter/execution/execution.go

@@ -10,26 +10,23 @@ import (
 type Node interface {
 	Name() string
 	URL() string
+	Bootstrapped() bool
+	Bootstrap(ctx context.Context) error
 	SyncStatus(ctx context.Context) (*SyncStatus, error)
 }
 
 type node struct {
 	name    string
 	url     string
-	client  ethclient.Client
+	client  *ethclient.Client
 	log     logrus.FieldLogger
 	metrics Metrics
 }
 
 func NewExecutionNode(ctx context.Context, log logrus.FieldLogger, name string, url string, metrics Metrics) (*node, error) {
-	// Make a dial call since its easier to create the client. We don't actually care if the
-	// client is alive or not at this point.
-	client, _ := ethclient.Dial(url)
-
 	return &node{
 		name:    name,
 		url:     url,
-		client:  *client,
 		log:     log,
 		metrics: metrics,
 	}, nil
@@ -43,6 +40,20 @@ func (e *node) URL() string {
 	return e.url
 }
 
+func (e *node) Bootstrapped() bool {
+	return e.client != nil
+}
+
+func (e *node) Bootstrap(ctx context.Context) error {
+	client, err := ethclient.Dial(e.url)
+	if err != nil {
+		return err
+	}
+
+	e.client = client
+	return nil
+}
+
 func (e *node) SyncStatus(ctx context.Context) (*SyncStatus, error) {
 	status, err := e.client.SyncProgress(ctx)
 	if err != nil {