Refactor of system/memory metricset

libbeat/metric/system/process/process.go

@@ -32,7 +32,7 @@ import (
 	"github.com/elastic/beats/v7/libbeat/common"
 	"github.com/elastic/beats/v7/libbeat/common/match"
 	"github.com/elastic/beats/v7/libbeat/logp"
-	"github.com/elastic/beats/v7/libbeat/metric/system/memory"
+	sysinfo "github.com/elastic/go-sysinfo"
 	sigar "github.com/elastic/gosigar"
 	"github.com/elastic/gosigar/cgroup"
 )
@@ -288,12 +288,20 @@ func GetOwnResourceUsageTimeInMillis() (int64, int64, error) {
 
 func (procStats *Stats) getProcessEvent(process *Process) common.MapStr {
 
+	// This is a holdover until we migrate this library to metricbeat/internal
+	// At which point we'll use the memory code there.
 	var totalPhyMem uint64
-	baseMem, err := memory.Get()
+	host, err := sysinfo.Host()
 	if err != nil {
-		procStats.logger.Warnf("Getting memory details: %v", err)
+		procStats.logger.Warnf("Getting host details: %v", err)
 	} else {
-		totalPhyMem = baseMem.Mem.Total
+		memStats, err := host.Memory()
+		if err != nil {
+			procStats.logger.Warnf("Getting memory details: %v", err)
+		} else {
+			totalPhyMem = memStats.Total
+		}
+
 	}
 
 	proc := common.MapStr{

metricbeat/internal/metrics/fold.go

@@ -0,0 +1,44 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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 metrics
+
+import (
+	"github.com/elastic/go-structform"
+)
+
+// Fold implements the folder interface for OptUint
+func (in *OptUint) Fold(v structform.ExtVisitor) error {
+	if in.exists == true {
+		value := in.value
+		v.OnUint64(value)
+	} else {
+		v.OnNil()
+	}
+	return nil
+}
+
+// Fold implements the folder interface for OptUint
+func (in *OptFloat) Fold(v structform.ExtVisitor) error {
+	if in.exists == true {
+		value := in.value
+		v.OnFloat64(value)
+	} else {
+		v.OnNil()
+	}
+	return nil
+}