Add start of sys exporter

cmd/server/main.go

@@ -1,7 +1,30 @@
 package main
 
-import "fmt"
+import (
+	"context"
+	"fmt"
+	"net/http"
+
+	"git.faercol.me/monitoring/sys-exporter/registry"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+
+	_ "git.faercol.me/monitoring/sys-exporter/collector/pacman"
+	_ "git.faercol.me/monitoring/sys-exporter/collector/uptime"
+)
+
+// type gatherer struct {
+// 	reg *prometheus.Registry
+// }
+
+// func (g *gatherer) Gather() (pcm.MetricFamily, error) {
+// 	return g.reg.
+// }
 
 func main() {
 	fmt.Println("starting server")
+
+	registry.R.Run(context.Background())
+
+	http.Handle("/metrics", promhttp.HandlerFor(registry.R.PromRegistry(), promhttp.HandlerOpts{}))
+	http.ListenAndServe(":2112", nil)
 }

collector/collector.go

@@ -0,0 +1,13 @@
+package collector
+
+import (
+	"context"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type Collector interface {
+	Collect() interface{}
+	PromCollector() prometheus.Collector
+	Run(ctx context.Context)
+}

collector/pacman/pacman.go

@@ -0,0 +1,108 @@
+package pacman
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+	"strings"
+	"time"
+
+	"git.faercol.me/monitoring/sys-exporter/registry"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	totalLabel   = "total"
+	updatesLabel = "updates"
+)
+
+func listCommandLines(command string, args ...string) (int, error) {
+	cmd := exec.Command(command, args...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return 0, fmt.Errorf("failed to run command: %w (%s)", err, string(out))
+	}
+
+	return len(strings.Split(string(out), "\n")), nil
+}
+
+type PacmanCollector struct {
+	installedPackages int
+	promPackages      *prometheus.GaugeVec
+	pendingUpdates    int
+	updateFreq        time.Duration
+}
+
+func (c *PacmanCollector) Collect() interface{} {
+	return map[string]int{
+		"installed_packages": c.installedPackages,
+		"pending_updates":    c.pendingUpdates,
+	}
+}
+
+func (c *PacmanCollector) updateInstalledPackages() error {
+	count, err := listCommandLines("/sbin/pacman", "-Q")
+	if err != nil {
+		return fmt.Errorf("failed to count installed packages: %w", err)
+	}
+
+	c.installedPackages = count
+	c.promPackages.WithLabelValues(totalLabel).Set(float64(count))
+	return nil
+}
+
+func (c *PacmanCollector) updatePendingUpdates() error {
+	updateCmd := exec.Command("/sbin/pacman", "-Sy")
+	if out, err := updateCmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("failed to update pacman cache: %w (%s)", err, string(out))
+	}
+
+	count, err := listCommandLines("/sbin/pacman", "-Qu")
+	if err != nil {
+		return fmt.Errorf("failed to count updated packages: %w", err)
+	}
+
+	c.pendingUpdates = count
+	c.promPackages.WithLabelValues(updatesLabel).Set(float64(count))
+	return nil
+}
+
+func (c *PacmanCollector) Run(ctx context.Context) {
+	if err := c.updateInstalledPackages(); err != nil {
+		fmt.Printf("Failed to init count of installed packages: %s\n", err)
+	}
+	if err := c.updatePendingUpdates(); err != nil {
+		fmt.Printf("Failed to init count of updates: %s\n", err)
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(c.updateFreq):
+			if err := c.updateInstalledPackages(); err != nil {
+				fmt.Printf("Failed to update count of installed packages: %s\n", err)
+			}
+			if err := c.updatePendingUpdates(); err != nil {
+				fmt.Printf("Failed to update count of updates: %s\n", err)
+			}
+		}
+	}
+}
+
+func (c *PacmanCollector) PromCollector() prometheus.Collector {
+	return c.promPackages
+}
+
+func New() *PacmanCollector {
+	c := PacmanCollector{
+		updateFreq:   5 * time.Minute,
+		promPackages: prometheus.NewGaugeVec(prometheus.GaugeOpts{Namespace: "packages", Subsystem: "pacman", Name: "packages_count", Help: "Count of pacman packages"}, []string{"status"}),
+	}
+
+	return &c
+}
+
+func init() {
+	registry.R.MustRegisterCollector("packages.pacman", New())
+}

collector/uptime/uptime.go

@@ -0,0 +1,84 @@
+package uptime
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.faercol.me/monitoring/sys-exporter/registry"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const procUptimeLocation = "/proc/uptime"
+
+type UptimeCollector struct {
+	ctx              context.Context
+	procFileLocation string
+	uptimeFreq       time.Duration
+	uptime           time.Duration
+	uptimeProm       prometheus.Gauge
+}
+
+func (c *UptimeCollector) Collect() interface{} {
+	return c.uptime
+}
+
+func (c *UptimeCollector) update() error {
+	fileContent, err := os.ReadFile(c.procFileLocation)
+	if err != nil {
+		return fmt.Errorf("failed to read uptime file: %w", err)
+	}
+
+	uptimeVals := strings.Split(string(fileContent), " ")
+	if len(uptimeVals) != 2 {
+		return fmt.Errorf("invalid format for /proc/uptime: %q", string(fileContent))
+	}
+
+	uptimeFloat, err := strconv.ParseFloat(uptimeVals[0], 64)
+	if err != nil {
+		return fmt.Errorf("invalid uptime format for float %s: %w", uptimeVals[0], err)
+	}
+
+	c.uptime = time.Duration(int(uptimeFloat)) * time.Second
+	c.uptimeProm.Set(uptimeFloat)
+	return nil
+}
+
+func (c *UptimeCollector) PromCollector() prometheus.Collector {
+	return c.uptimeProm
+}
+
+func (c *UptimeCollector) Run(ctx context.Context) {
+	if err := c.update(); err != nil {
+		fmt.Printf("Failed to init collector: %s\n", err)
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(c.uptimeFreq):
+			if err := c.update(); err != nil {
+				fmt.Printf("Failed to update collector: %s\n", err)
+			}
+		}
+	}
+}
+
+func New() *UptimeCollector {
+	return &UptimeCollector{
+		ctx:              context.TODO(),
+		procFileLocation: procUptimeLocation,
+		uptimeFreq:       1 * time.Second,
+		uptime:           0,
+		uptimeProm:       prometheus.NewGauge(prometheus.GaugeOpts{Namespace: "system", Name: "uptime_nanosec", Help: "System uptime in nanoseconds"}),
+	}
+
+}
+
+func init() {
+	registry.R.MustRegisterCollector("system.uptime", New())
+}

go.mod

@@ -1,3 +1,17 @@
 module git.faercol.me/monitoring/sys-exporter
 
 go 1.23.3
+
+require github.com/prometheus/client_golang v1.20.5
+
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/klauspost/compress v1.17.9 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/prometheus/client_model v0.6.1 // indirect
+	github.com/prometheus/common v0.55.0 // indirect
+	github.com/prometheus/procfs v0.15.1 // indirect
+	golang.org/x/sys v0.22.0 // indirect
+	google.golang.org/protobuf v1.34.2 // indirect
+)

go.sum

@@ -0,0 +1,24 @@
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
+github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
+github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
+github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/klauspost/compress v1.17.9 h1:6KIumPrER1LHsvBVuDa0r5xaG0Es51mhhB9BQB2qeMA=
+github.com/klauspost/compress v1.17.9/go.mod h1:Di0epgTjJY877eYKx5yC51cX2A2Vl2ibi7bDH9ttBbw=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
+github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
+github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
+github.com/prometheus/client_golang v1.20.5 h1:cxppBPuYhUnsO6yo/aoRol4L7q7UFfdm+bR9r+8l63Y=
+github.com/prometheus/client_golang v1.20.5/go.mod h1:PIEt8X02hGcP8JWbeHyeZ53Y/jReSnHgO035n//V5WE=
+github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
+github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
+github.com/prometheus/common v0.55.0 h1:KEi6DK7lXW/m7Ig5i47x0vRzuBsHuvJdi5ee6Y3G1dc=
+github.com/prometheus/common v0.55.0/go.mod h1:2SECS4xJG1kd8XF9IcM1gMX6510RAEL65zxzNImwdc8=
+github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
+github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
+golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
+golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+google.golang.org/protobuf v1.34.2 h1:6xV6lTsCfpGD21XK49h7MhtcApnLqkfYgPcdHftf6hg=
+google.golang.org/protobuf v1.34.2/go.mod h1:qYOHts0dSfpeUzUFpOMr/WGzszTmLH+DiWniOlNbLDw=

registry/registry.go

@@ -0,0 +1,42 @@
+package registry
+
+import (
+	"context"
+
+	"git.faercol.me/monitoring/sys-exporter/collector"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var R CollectorRegistry
+
+type CollectorRegistry struct {
+	promRegistry *prometheus.Registry
+	collectors   map[string]collector.Collector
+}
+
+func (r *CollectorRegistry) RegisterCollector(name string, c collector.Collector) error {
+	r.collectors[name] = c
+	return r.promRegistry.Register(c.PromCollector())
+}
+
+func (r *CollectorRegistry) MustRegisterCollector(name string, c collector.Collector) {
+	r.collectors[name] = c
+	r.promRegistry.MustRegister(c.PromCollector())
+}
+
+func (r *CollectorRegistry) PromRegistry() *prometheus.Registry {
+	return r.promRegistry
+}
+
+func (r *CollectorRegistry) Run(ctx context.Context) {
+	for _, c := range r.collectors {
+		go c.Run(ctx)
+	}
+}
+
+func init() {
+	R = CollectorRegistry{
+		promRegistry: prometheus.NewRegistry(),
+		collectors:   make(map[string]collector.Collector),
+	}
+}