Always lowercase FQDN

.changelog/180.txt

@@ -0,0 +1,4 @@
+```release-note:enhancement
+Lowercase the returned OS.Hostname and FQDN values as per Elastic
+Common Schema (ECS) guidelines for the `host.name` field.
+```

providers/aix/host_aix_ppc64.go

@@ -33,6 +33,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/joeshaw/multierror"
@@ -173,7 +174,7 @@ func (r *reader) hostname(h *host) {
 	if r.addErr(err) {
 		return
 	}
-	h.info.Hostname = v
+	h.info.Hostname = strings.ToLower(v)
 }
 
 func (r *reader) network(h *host) {

providers/darwin/host_darwin.go

@@ -23,6 +23,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/joeshaw/multierror"
@@ -213,7 +214,7 @@ func (r *reader) hostname(h *host) {
 	if r.addErr(err) {
 		return
 	}
-	h.info.Hostname = v
+	h.info.Hostname = strings.ToLower(v)
 }
 
 func (r *reader) network(h *host) {

providers/linux/host_linux.go

@@ -23,6 +23,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/joeshaw/multierror"
@@ -212,7 +213,7 @@ func (r *reader) hostname(h *host) {
 	if r.addErr(err) {
 		return
 	}
-	h.info.Hostname = v
+	h.info.Hostname = strings.ToLower(v)
 }
 
 func (r *reader) network(h *host) {

providers/shared/fqdn.go

@@ -57,7 +57,7 @@ func fqdn(hostname string) (string, error) {
 			err)
 	}
 	if cname != "" {
-		return strings.TrimSuffix(cname, "."), nil
+		return strings.ToLower(strings.TrimSuffix(cname, ".")), nil
 	}
 
 	ips, err := net.LookupIP(hostname)
@@ -70,7 +70,7 @@ func fqdn(hostname string) (string, error) {
 		if err != nil || len(names) == 0 {
 			continue
 		}
-		return strings.TrimSuffix(names[0], "."), nil
+		return strings.ToLower(strings.TrimSuffix(names[0], ".")), nil
 	}
 
 	return "", errs

providers/shared/fqdn_test.go

@@ -51,6 +51,11 @@ func TestFQDN(t *testing.T) {
 			expectedFQDN:     "",
 			expectedErrRegex: makeErrorRegex("foobarbaz"),
 		},
+		"long_mixed_case_hostname": {
+			osHostname:       "eLaSTic.co",
+			expectedFQDN:     "elastic.co",
+			expectedErrRegex: "",
+		},
 	}
 
 	for name, test := range tests {

providers/windows/host_windows.go

@@ -90,7 +90,7 @@ func (h *host) FQDN() (string, error) {
 		return "", fmt.Errorf("could not get windows FQDN: %s", err)
 	}
 
-	return strings.TrimSuffix(fqdn, "."), nil
+	return strings.ToLower(strings.TrimSuffix(fqdn, ".")), nil
 }
 
 func newHost() (*host, error) {
@@ -149,7 +149,7 @@ func (r *reader) hostname(h *host) {
 	if r.addErr(err) {
 		return
 	}
-	h.info.Hostname = v
+	h.info.Hostname = strings.ToLower(v)
 }
 
 func getComputerNameEx(name uint32) (string, error) {

types/host.go

@@ -26,6 +26,8 @@ type Host interface {
 	CPUTimer
 	Info() HostInfo
 	Memory() (*HostMemoryInfo, error)
+
+	// FQDN returns the fully-qualified domain name of the host, lowercased.
 	FQDN() (string, error)
 }
 
@@ -67,7 +69,7 @@ type HostInfo struct {
 	Architecture      string    `json:"architecture"`            // Hardware architecture (e.g. x86_64, arm, ppc, mips).
 	BootTime          time.Time `json:"boot_time"`               // Host boot time.
 	Containerized     *bool     `json:"containerized,omitempty"` // Is the process containerized.
-	Hostname          string    `json:"name"`                    // Hostname
+	Hostname          string    `json:"name"`                    // Hostname, lowercased.
 	IPs               []string  `json:"ip,omitempty"`            // List of all IPs.
 	KernelVersion     string    `json:"kernel_version"`          // Kernel version.
 	MACs              []string  `json:"mac"`                     // List of MAC addresses.