Add sysinfo collector

cmd/server/main.go

@@ -14,6 +14,7 @@ import (
 	_ "git.faercol.me/monitoring/sys-exporter/collector/loadavg"
 	_ "git.faercol.me/monitoring/sys-exporter/collector/meminfo"
 	_ "git.faercol.me/monitoring/sys-exporter/collector/pacman"
+	_ "git.faercol.me/monitoring/sys-exporter/collector/sysinfo"
 	_ "git.faercol.me/monitoring/sys-exporter/collector/systemd"
 	_ "git.faercol.me/monitoring/sys-exporter/collector/uptime"
 )

collector/sysinfo/sysinfo.go

@@ -0,0 +1,167 @@
+package sysinfo
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"regexp"
+	"strings"
+	"time"
+
+	"git.faercol.me/monitoring/sys-exporter/registry"
+	"github.com/prometheus/client_golang/prometheus"
+	"go.uber.org/zap"
+)
+
+var versionRegexp = regexp.MustCompile(`(?m)^(\w+) version ([^ ]+) .*$`)
+
+const (
+	hosnameFile    = "/etc/hostname"
+	osRealeaseFile = "/etc/os-release"
+	versionFile    = "/proc/version"
+)
+
+var labels = []string{
+	"hostname",
+	"kernel",
+	"os",
+	"distro",
+	"distro_version",
+}
+
+type SysinfoCollector struct {
+	hostname      string
+	kernelVersion string
+	os            string
+	distro        string
+	distroVersion string
+
+	hostnameFile  string
+	osReleaseFile string
+	versionFile   string
+
+	promExporter *prometheus.GaugeVec
+	updateFreq   time.Duration
+	l            *zap.SugaredLogger
+}
+
+func (c *SysinfoCollector) Collect() interface{} {
+	return nil
+}
+
+func (c *SysinfoCollector) labels() prometheus.Labels {
+	return prometheus.Labels{
+		"hostname":       c.hostname,
+		"kernel":         c.kernelVersion,
+		"os":             c.os,
+		"distro":         c.distro,
+		"distro_version": c.distroVersion,
+	}
+}
+
+func (c *SysinfoCollector) updateHostname() error {
+	rawHostname, err := os.ReadFile(c.hostnameFile)
+	if err != nil {
+		return err
+	}
+
+	c.hostname = strings.TrimSpace(string(rawHostname))
+	return nil
+}
+
+func (c *SysinfoCollector) updateKernelVersion() error {
+	rawVersion, err := os.ReadFile(c.versionFile)
+	if err != nil {
+		return err
+	}
+
+	if matches := versionRegexp.FindAllStringSubmatch(string(rawVersion), -1); matches == nil {
+		return errors.New("failed to match /proc/version")
+	} else {
+		c.os = matches[0][1]
+		c.kernelVersion = matches[0][2]
+	}
+
+	return nil
+}
+
+func (c *SysinfoCollector) updateDistro() error {
+	rawContent, err := os.ReadFile(c.osReleaseFile)
+	if err != nil {
+		return err
+	}
+
+	releaseData, err := parseOSRelease(rawContent)
+	if err != nil {
+		return fmt.Errorf("failed to parse /etc/os-release file: %w", err)
+	}
+
+	switch releaseData["ID"] {
+	case "arch":
+		c.distro = "Arch Linux"
+		c.distroVersion = releaseData["BUILD_ID"]
+	case "debian":
+		c.distro = "Debian GNU/Linux"
+		c.distroVersion = releaseData["VERSION"]
+	default:
+		c.distro = releaseData["NAME"]
+	}
+
+	return nil
+}
+
+func (c *SysinfoCollector) update() error {
+	if err := c.updateKernelVersion(); err != nil {
+		return fmt.Errorf("failed to get kernel version: %w", err)
+	}
+	if err := c.updateHostname(); err != nil {
+		return fmt.Errorf("failed to get hostname: %w", err)
+	}
+	if err := c.updateDistro(); err != nil {
+		return fmt.Errorf("failed to get distro info: %w", err)
+	}
+
+	c.promExporter.With(c.labels()).Set(1)
+	return nil
+}
+
+func (c *SysinfoCollector) Run(ctx context.Context, l *zap.SugaredLogger) {
+	c.l = l
+
+	c.l.Debug("Initializing collector")
+	if err := c.update(); err != nil {
+		c.l.Errorf("Failed to init collector: %s\n", err)
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			c.l.Debug("Stopping collector")
+			return
+		case <-time.After(c.updateFreq):
+			c.l.Debug("Updating collector")
+			if err := c.update(); err != nil {
+				c.l.Errorf("Failed to update collector: %s\n", err)
+			}
+		}
+	}
+}
+
+func (c *SysinfoCollector) PromCollector() prometheus.Collector {
+	return c.promExporter
+}
+
+func New() *SysinfoCollector {
+	return &SysinfoCollector{
+		updateFreq:    30 * time.Minute,
+		hostnameFile:  hosnameFile,
+		osReleaseFile: osRealeaseFile,
+		versionFile:   versionFile,
+		promExporter:  prometheus.NewGaugeVec(prometheus.GaugeOpts{Namespace: "system", Name: "info", Help: "System global information"}, labels),
+	}
+}
+
+func init() {
+	registry.R.MustRegisterCollector("system.info", New())
+}

collector/sysinfo/utils.go

@@ -0,0 +1,29 @@
+package sysinfo
+
+import (
+	"fmt"
+	"strings"
+)
+
+func parseOSRelease(content []byte) (map[string]string, error) {
+	res := make(map[string]string)
+
+	for _, line := range strings.Split(string(content), "\n") {
+		if line == "" {
+			continue
+		}
+
+		lineVals := strings.SplitN(line, "=", 2)
+		if len(lineVals) != 2 {
+			return nil, fmt.Errorf("impossible to split line %q", line)
+		}
+
+		if _, ok := res[lineVals[0]]; ok {
+			return nil, fmt.Errorf("duplicate key %q", lineVals[0])
+		}
+
+		res[lineVals[0]] = lineVals[1]
+	}
+
+	return res, nil
+}

debian/sys-exporter/etc/sys-exporter/config.yml

@@ -5,3 +5,4 @@ collectors:
   - system.meminfo
   - services.systemd
   - system.uptime
+  - system.info