Fix doc build issues happening in linux/memory (#27381)

* fix doc build issues

* add changelog

* move tests to linux-only

CHANGELOG.next.asciidoc

@@ -197,6 +197,7 @@ https:/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Improve `perfmon` metricset performance. {pull}26886[26886]
 - Preserve annotations in a kubernetes namespace metadata {pull}27045[27045]
 - Allow conditional processing in `decode_xml` and `decode_xml_wineventlog`. {pull}27159[27159]
+- Fix build constraint that caused issues with doc builds. {pull}27381[27381]
 
 *Auditbeat*
 

metricbeat/internal/metrics/memory/memory_helpers.go

@@ -0,0 +1,79 @@
+// 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 memory
+
+import (
+ "bufio"
+ "bytes"
+ "io"
+ "io/ioutil"
+ "path/filepath"
+ "strconv"
+ "strings"
+
+ "github.com/pkg/errors"
+)
+
+// ParseMeminfo parses the contents of /proc/meminfo into a hashmap
+func ParseMeminfo(rootfs string) (map[string]uint64, error) {
+ table := map[string]uint64{}
+
+ meminfoPath := filepath.Join(rootfs, "/proc/meminfo")
+ err := readFile(meminfoPath, func(line string) bool {
+ fields := strings.Split(line, ":")
+
+ if len(fields) != 2 {
+ return true // skip on errors
+ }
+
+ valueUnit := strings.Fields(fields[1])
+ value, err := strconv.ParseUint(valueUnit[0], 10, 64)
+ if err != nil {
+ return true // skip on errors
+ }
+
+ if len(valueUnit) > 1 && valueUnit[1] == "kB" {
+ value *= 1024
+ }
+ table[fields[0]] = value
+
+ return true
+ })
+ return table, err
+}
+
+func readFile(file string, handler func(string) bool) error {
+ contents, err := ioutil.ReadFile(file)
+ if err != nil {
+ return errors.Wrapf(err, "error reading file %s", file)
+ }
+
+ reader := bufio.NewReader(bytes.NewBuffer(contents))
+
+ for {
+ line, _, err := reader.ReadLine()
+ if err == io.EOF {
+ break
+ }
+ if !handler(string(line)) {
+ break
+ }
+ }
+
+ return nil
+}

metricbeat/internal/metrics/memory/memory_linux.go

@@ -18,14 +18,6 @@
 package memory
 
 import (
- "bufio"
- "bytes"
- "io"
- "io/ioutil"
- "path/filepath"
- "strconv"
- "strings"
-
  "github.com/pkg/errors"
 
  "github.com/elastic/beats/v7/libbeat/opt"
@@ -92,52 +84,3 @@ func get(rootfs string) (Memory, error) {
  return memData, nil
 
 }
-
-// ParseMeminfo parses the contents of /proc/meminfo into a hashmap
-func ParseMeminfo(rootfs string) (map[string]uint64, error) {
- table := map[string]uint64{}
-
- meminfoPath := filepath.Join(rootfs, "/proc/meminfo")
- err := readFile(meminfoPath, func(line string) bool {
- fields := strings.Split(line, ":")
-
- if len(fields) != 2 {
- return true // skip on errors
- }
-
- valueUnit := strings.Fields(fields[1])
- value, err := strconv.ParseUint(valueUnit[0], 10, 64)
- if err != nil {
- return true // skip on errors
- }
-
- if len(valueUnit) > 1 && valueUnit[1] == "kB" {
- value *= 1024
- }
- table[fields[0]] = value
-
- return true
- })
- return table, err
-}
-
-func readFile(file string, handler func(string) bool) error {
- contents, err := ioutil.ReadFile(file)
- if err != nil {
- return errors.Wrapf(err, "error reading file %s", file)
- }
-
- reader := bufio.NewReader(bytes.NewBuffer(contents))
-
- for {
- line, _, err := reader.ReadLine()
- if err == io.EOF {
- break
- }
- if !handler(string(line)) {
- break
- }
- }
-
- return nil
-}

metricbeat/module/linux/memory/data.go

@@ -15,8 +15,6 @@
 // specific language governing permissions and limitations
 // under the License.
 
-// +build linux
-
 package memory
 
 import (
@@ -139,7 +137,7 @@ func GetVMStat() (*sysinfotypes.VMStatInfo, error) {
  }
  vmstatHandle, ok := h.(sysinfotypes.VMStat)
  if !ok {
- return nil, errors.Wrap(err, "VMStat not available for platform")
+ return nil, errors.New("VMStat not available for platform")
  }
  info, err := vmstatHandle.VMStat()
  if err != nil {

metricbeat/module/linux/memory/memory.go

@@ -15,8 +15,6 @@
 // specific language governing permissions and limitations
 // under the License.
 
-// +build linux
-
 package memory
 
 import (

metricbeat/module/linux/memory/memory_test.go → metricbeat/module/linux/memory/memory_linux_test.go

@@ -15,8 +15,6 @@
 // specific language governing permissions and limitations
 // under the License.
 
-// +build linux
-
 package memory
 
 import (