Install actions after setting up metrics. (#2717)

Running Horizon with ADMIN_PORT enabled will cause a panic when trying
to fetch the metrics since it was being setup before initializing the
metrics registry.

services/horizon/internal/app.go

@@ -476,9 +476,6 @@ func (a *App) init() {
 	// This parameter will be removed soon.
 	a.web.mustInstallMiddlewares(a, a.config.ConnectionTimeout)
 
-	// web.actions
-	a.web.mustInstallActions(a.config, a.paths, a.historyQ.Session, a.metrics)
-
 	// metrics and log.metrics
 	a.metrics = metrics.NewRegistry()
 	for level, meter := range *logmetrics.DefaultMetrics {
@@ -488,6 +485,9 @@ func (a *App) init() {
 	// db-metrics
 	initDbMetrics(a)
 
+	// web.actions
+	a.web.mustInstallActions(a.config, a.paths, a.historyQ.Session, a.metrics)
+
 	// ingest.metrics
 	initIngestMetrics(a)
 

services/horizon/internal/app_test.go

@@ -3,6 +3,8 @@ package horizon
 import (
 	"net/http"
 	"testing"
+
+	"github.com/stellar/go/services/horizon/internal/test"
 )
 
 func TestGenericHTTPFeatures(t *testing.T) {
@@ -37,6 +39,10 @@ func TestMetrics(t *testing.T) {
 	ht := StartHTTPTest(t, "base")
 	defer ht.Finish()
 
+	adminRouterRH := test.NewRequestHelper(ht.App.web.internalRouter)
+	w := adminRouterRH.Get("/metrics")
+	ht.Assert.Equal(200, w.Code)
+
 	hl := ht.App.historyLatestLedgerGauge
 	he := ht.App.historyElderLedgerGauge
 	cl := ht.App.coreLatestLedgerGauge