Adding OS version info to the nodes' Info struct

This is needed so that we can add OS version constraints in Swarmkit, which
does require the engine to report its host's OS version (see
moby/swarmkit#2770).

The OS version is parsed from the `os-release` file on Linux, and from the
`ReleaseId` string value of the `SOFTWARE\Microsoft\Windows NT\CurrentVersion`
registry key on Windows.

Added unit tests when possible, as well as Prometheus metrics.

Signed-off-by: Jean Rouge <rougej+github@gmail.com>

api/swagger.yaml

@@ -3840,6 +3840,17 @@ definitions:
           or "Windows Server 2016 Datacenter"
         type: "string"
         example: "Alpine Linux v3.5"
+      OSVersion:
+        description: |
+          Version of the host's operating system
+
+          <p><br /></p>
+
+          > **Note**: The information returned in this field, including its
+          > very existence, and the formatting of values, should not be considered
+          > stable, and may change without notice.
+        type: "string"
+        example: "16.04"
       OSType:
         description: |
           Generic type of the operating system of the host, as returned by the

api/types/types.go

@@ -177,6 +177,7 @@ type Info struct {
 	NEventsListener    int
 	KernelVersion      string
 	OperatingSystem    string
+	OSVersion          string
 	OSType             string
 	Architecture       string
 	IndexServerAddress string

daemon/daemon.go

@@ -1061,6 +1061,7 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 		info.KernelVersion,
 		info.OperatingSystem,
 		info.OSType,
+		info.OSVersion,
 		info.ID,
 	).Set(1)
 	engineCpus.Set(float64(info.NCPU))

daemon/info.go

@@ -21,11 +21,14 @@ import (
 	"github.com/docker/docker/pkg/system"
 	"github.com/docker/docker/registry"
 	"github.com/docker/go-connections/sockets"
+	"github.com/docker/go-metrics"
 	"github.com/sirupsen/logrus"
 )
 
 // SystemInfo returns information about the host server the daemon is running on.
 func (daemon *Daemon) SystemInfo() (*types.Info, error) {
+	defer metrics.StartTimer(hostInfoFunctions.WithValues("system_info"))()
+
 	sysInfo := sysinfo.New(true)
 	cRunning, cPaused, cStopped := stateCtr.get()
 
@@ -49,6 +52,7 @@ func (daemon *Daemon) SystemInfo() (*types.Info, error) {
 		NEventsListener:    daemon.EventsService.SubscribersCount(),
 		KernelVersion:      kernelVersion(),
 		OperatingSystem:    operatingSystem(),
+		OSVersion:          osVersion(),
 		IndexServerAddress: registry.IndexServer,
 		OSType:             platform.OSType,
 		Architecture:       platform.Architecture,
@@ -82,6 +86,8 @@ func (daemon *Daemon) SystemInfo() (*types.Info, error) {
 
 // SystemVersion returns version information about the daemon.
 func (daemon *Daemon) SystemVersion() types.Version {
+	defer metrics.StartTimer(hostInfoFunctions.WithValues("system_version"))()
+
 	kernelVersion := kernelVersion()
 
 	v := types.Version{
@@ -240,8 +246,9 @@ func memInfo() *system.MemInfo {
 	return memInfo
 }
 
-func operatingSystem() string {
-	var operatingSystem string
+func operatingSystem() (operatingSystem string) {
+	defer metrics.StartTimer(hostInfoFunctions.WithValues("operating_system"))()
+
 	if s, err := operatingsystem.GetOperatingSystem(); err != nil {
 		logrus.Warnf("Could not get operating system name: %v", err)
 	} else {
@@ -256,9 +263,21 @@ func operatingSystem() string {
 			operatingSystem += " (containerized)"
 		}
 	}
+
 	return operatingSystem
 }
 
+func osVersion() (version string) {
+	defer metrics.StartTimer(hostInfoFunctions.WithValues("os_version"))()
+
+	version, err := operatingsystem.GetOperatingSystemVersion()
+	if err != nil {
+		logrus.Warnf("Could not get operating system version: %v", err)
+	}
+
+	return version
+}
+
 func maskCredentials(rawURL string) string {
 	parsedURL, err := url.Parse(rawURL)
 	if err != nil || parsedURL.User == nil {

daemon/metrics.go

@@ -17,6 +17,7 @@ const metricsPluginType = "MetricsCollector"
 var (
 	containerActions          metrics.LabeledTimer
 	networkActions            metrics.LabeledTimer
+	hostInfoFunctions         metrics.LabeledTimer
 	engineInfo                metrics.LabeledGauge
 	engineCpus                metrics.Gauge
 	engineMemory              metrics.Gauge
@@ -38,15 +39,18 @@ func init() {
 	} {
 		containerActions.WithValues(a).Update(0)
 	}
+	hostInfoFunctions = ns.NewLabeledTimer("host_info_functions", "The number of seconds it takes to call functions gathering info about the host", "function")
 
 	networkActions = ns.NewLabeledTimer("network_actions", "The number of seconds it takes to process each network action", "action")
 	engineInfo = ns.NewLabeledGauge("engine", "The information related to the engine and the OS it is running on", metrics.Unit("info"),
 		"version",
 		"commit",
 		"architecture",
 		"graphdriver",
-		"kernel", "os",
+		"kernel",
+		"os",
 		"os_type",
+		"os_version",
 		"daemon_id", // ID is a randomly generated unique identifier (e.g. UUID4)
 	)
 	engineCpus = ns.NewGauge("engine_cpus", "The number of cpus that the host system of the engine has", metrics.Unit("cpus"))

pkg/parsers/operatingsystem/operatingsystem_linux.go

@@ -26,6 +26,24 @@ var (
 
 // GetOperatingSystem gets the name of the current operating system.
 func GetOperatingSystem() (string, error) {
+	if prettyName, err := getValueFromOsRelease("PRETTY_NAME"); err != nil {
+		return "", err
+	} else if prettyName != "" {
+		return prettyName, nil
+	}
+
+	// If not set, defaults to PRETTY_NAME="Linux"
+	// c.f. http://www.freedesktop.org/software/systemd/man/os-release.html
+	return "Linux", nil
+}
+
+// GetOperatingSystemVersion gets the version of the current operating system, as a string.
+func GetOperatingSystemVersion() (string, error) {
+	return getValueFromOsRelease("VERSION_ID")
+}
+
+// parses the os-release file and returns the value associated with `key`
+func getValueFromOsRelease(key string) (string, error) {
 	osReleaseFile, err := os.Open(etcOsRelease)
 	if err != nil {
 		if !os.IsNotExist(err) {
@@ -38,28 +56,25 @@ func GetOperatingSystem() (string, error) {
 	}
 	defer osReleaseFile.Close()
 
-	var prettyName string
+	var value string
+	keyWithTrailingEqual := key + "="
 	scanner := bufio.NewScanner(osReleaseFile)
 	for scanner.Scan() {
 		line := scanner.Text()
-		if strings.HasPrefix(line, "PRETTY_NAME=") {
+		if strings.HasPrefix(line, keyWithTrailingEqual) {
 			data := strings.SplitN(line, "=", 2)
-			prettyNames, err := shellwords.Parse(data[1])
+			values, err := shellwords.Parse(data[1])
 			if err != nil {
-				return "", fmt.Errorf("PRETTY_NAME is invalid: %s", err.Error())
+				return "", fmt.Errorf("%s is invalid: %s", key, err.Error())
 			}
-			if len(prettyNames) != 1 {
-				return "", fmt.Errorf("PRETTY_NAME needs to be enclosed by quotes if they have spaces: %s", data[1])
+			if len(values) != 1 {
+				return "", fmt.Errorf("%s needs to be enclosed by quotes if they have spaces: %s", key, data[1])
 			}
-			prettyName = prettyNames[0]
+			value = values[0]
 		}
 	}
-	if prettyName != "" {
-		return prettyName, nil
-	}
-	// If not set, defaults to PRETTY_NAME="Linux"
-	// c.f. http://www.freedesktop.org/software/systemd/man/os-release.html
-	return "Linux", nil
+
+	return value, nil
 }
 
 // IsContainerized returns true if we are running inside a container.