Initial commit

application/application.go

@@ -0,0 +1,81 @@
+package application
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	log "github.com/sirupsen/logrus"
+	"gopkg.in/yaml.v2"
+	"lostak.dev/pve-exporter/configuration"
+	"lostak.dev/pve-exporter/metrics"
+	"lostak.dev/pve-exporter/proxmox"
+)
+
+// Application context.
+type Application struct {
+	Configuration  *configuration.Configuration // Application configuration.
+	Router         *mux.Router                  // Gorilla MUX router instance.
+	Server         *http.Server                 // HTTP server instance.
+	MetricsManager *metrics.PveMetricsManager   // PVE metrics manager.
+	PveApiClient   *proxmox.PveApiClient        // PVE API client instance.
+}
+
+// Create new instance of the PVE exporter.
+func NewApplication(configPath string) *Application {
+	app := Application{}
+	app.Router = mux.NewRouter()
+
+	// Load configuration file.
+	file, err := os.ReadFile(configPath)
+	if err != nil {
+		log.Panicf("Can't open config.yaml. Error: %s.", err)
+	}
+
+	// Unmarshal configuration file.
+	if err := yaml.Unmarshal(file, &app.Configuration); err != nil {
+		log.Panicf("Can't parse config.yaml. Error: %s.", err)
+	}
+
+	// Validate configuration file.
+	err = app.Configuration.Validate()
+	if err != nil {
+		log.Fatalf("Configuration error: %s", err)
+	}
+
+	// Set log level.
+	log.SetLevel(log.AllLevels[app.Configuration.LogLevel])
+
+	// Create proxmox API client instance.
+	pvec := app.Configuration.PVE
+	app.PveApiClient = proxmox.NewPveApiClient(pvec.Hosts, pvec.Token.TokenId, pvec.Token.Secret)
+
+	// Create metrics collector.
+	app.MetricsManager = metrics.NewPveMetricsManager(app.PveApiClient, &app.Configuration.PVE)
+
+	return &app
+}
+
+// Initialize application internals such as HTTP server, router, PVE metrics scraper.
+func (app *Application) Start() {
+	// Prepare web server.
+	hostaddr := fmt.Sprintf("%s:%d", app.Configuration.Host, app.Configuration.Port)
+	app.Server = &http.Server{
+		Handler:      app.Router,
+		Addr:         hostaddr,
+		WriteTimeout: 15 * time.Second,
+		ReadTimeout:  15 * time.Second,
+	}
+
+	// Prepare metrics handler
+	app.Router.Handle("/metrics", promhttp.Handler())
+
+	// Start the metrics manager.
+	app.MetricsManager.Start()
+
+	log.Infof("Proxmox exporter started on %s.", hostaddr)
+	log.Fatal(app.Server.ListenAndServe())
+}