(PATCH) Add structured logging, refactoring exporter & config initialization

Author: JRHemmen

README.md

@@ -89,7 +89,7 @@ Example exporter.env:
 PC_CLUSTER_NAME=your-pc-cluster-name
 PC_CLUSTER_URL=https://your-pc-cluster.yourdomain.com:9440
 PC_API_VERSION=v3 (Optional, defaults to v4. Supports v3, v4b1, v4)
-CLUSTER_REFRESH_INTERVAL=1800 (Seconds. Optional, defaults to 0, i.e. no refreshing)
+CLUSTER_REFRESH_INTERVAL=1800 (Seconds. Optional, defaults to 30 minutes)
 CLUSTER_PREFIX=optional-cluster-prefix to filter cluster names
 
 ### For HashiCorp Vault only
@@ -98,7 +98,7 @@ VAULT_NAMESPACE=production
 VAULT_ENGINE_NAME=NutanixKV2
 VAULT_ROLE_ID=12345678-1234-5678-1234-567812345678
 VAULT_SECRET_ID=12345678-1234-5678-1234-567812345678
-VAULT_REFRESH_INTERVAL=1500 (Seconds. Optional, defaults to 0, i.e. no refreshing)
+VAULT_REFRESH_INTERVAL=1500 (Seconds. Optional, defaults to 30 minutes)
 PE_TASK_ACCOUNT=PETaskAccount
 PC_TASK_ACCOUNT=PCTaskAccount
 

cmd/nutanix-exporter/main.go

@@ -17,24 +17,58 @@ package main
 
 import (
 	"context"
+	"log/slog"
 	"os"
 	"os/signal"
 	"syscall"
 
-	"github.com/ingka-group/nutanix-exporter/internal/exporter"
+	"github.com/ingka-group/nutanix-exporter/internal/auth"
+	"github.com/ingka-group/nutanix-exporter/internal/config"
+	"github.com/ingka-group/nutanix-exporter/internal/service"
 )
 
 // main is the entrypoint of the exporter
 func main() {
 
-	// Initialize exporter
-	go exporter.Init()
+	// Set up global structured Logging
+	logger := slog.New(slog.NewTextHandler(os.Stdout, nil))
+	slog.SetDefault(logger)
 
-	// Wait for shutdown signal and stop gracefully
+	// Load configuration
+	cfg, err := config.NewConfig()
+	if err != nil {
+		slog.Error("Failed to load configuration", "error", err)
+		os.Exit(1)
+	}
+
+	// Create credential provider based on configuration
+	var credProvider auth.CredentialProvider
+	if cfg.VaultAddress != "" {
+		credProvider, err = auth.NewVaultCredentialProvider(cfg)
+		if err != nil {
+			slog.Error("Failed to create vault credential provider", "error", err)
+			os.Exit(1)
+		}
+		slog.Info("Using Vault credential provider")
+	} else {
+		credProvider = auth.NewEnvCredentialProvider()
+		slog.Info("Using environment variable credential provider")
+	}
+
+	// Create and start exporter service
+	exporterService := service.NewExporterService(cfg, credProvider)
+	if err := exporterService.Start(); err != nil {
+		slog.Error("Failed to start exporter service", "error", err)
+		os.Exit(1)
+	}
+
+	// Wait for shutdown signal
 	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
 	defer stop()
 	<-ctx.Done()
-	stop()
 
-	// test
+	// Stop services and disconnect clients
+	stop()
+	exporterService.Stop()
+	slog.Info("Graceful shutdown completed")
 }

go.mod

@@ -10,6 +10,7 @@ require (
 
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/caarlos0/env/v11 v11.3.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/hashicorp/go-retryablehttp v0.7.7 // indirect

go.sum

@@ -1,5 +1,7 @@
 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/caarlos0/env/v11 v11.3.1 h1:cArPWC15hWmEt+gWk7YBi7lEXTXCvpaSdCiZE2X5mCA=
+github.com/caarlos0/env/v11 v11.3.1/go.mod h1:qupehSf/Y0TUTsxKywqRt/vJjN5nz6vauiYEUUr8P4U=
 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/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=

internal/auth/auth.go

@@ -22,23 +22,10 @@ limitations under the License.
 
 package auth
 
-import (
-	"log"
-	"os"
-)
-
 // CredentialProvider defines which functions a credential provider for Nutanix
 // cluster authentication has to implement.
 type CredentialProvider interface {
 	GetPCCreds(cluster string) (string, string, error)
 	GetPECreds(cluster string) (string, string, error)
-}
-
-// getEnvOrFatal returns the value of the specified environment variable or exits the program.
-func getEnvOrFatal(envVar string) string {
-	value := os.Getenv(envVar)
-	if value == "" {
-		log.Fatalf("%s environment variable is not set", envVar)
-	}
-	return value
+	Refresh() error // For refreshable providers like Vault
 }

internal/auth/env.go

@@ -26,39 +26,33 @@ import (
 // cluster authentication credentials from environment variables.
 type EnvCredentialProvider struct{}
 
-// ConvertClusterName changes any characters that should not be used in
-// environment variables to an underscore (_).
-func ConvertClusterName(cluster string) string {
-	cluster = strings.ToUpper(cluster)
-
-	r, _ := regexp.Compile("[^A-Z_0-9]+")
-	cluster = r.ReplaceAllString(cluster, "_")
+// NewEnvCredentialProvider creates a new instance of EnvCredentialProvider.
+func NewEnvCredentialProvider() *EnvCredentialProvider {
+	return &EnvCredentialProvider{}
+}
 
-	return cluster
+// Refresh is a no-op for the EnvCredentialProvider since it does not maintain a state.
+func (e *EnvCredentialProvider) Refresh() error {
+	return nil
 }
 
 // getEnvVarsForCluster generates the names for the environment variables
 // that have to be used for providing login credentials of a Nutanix cluster.
-func getEnvVarsForCluster(cluster string, isPC bool) (string, string) {
-	var evU, evP string
-
+func (e *EnvCredentialProvider) getEnvVarsForCluster(cluster string, isPC bool) (string, string) {
 	if isPC {
-		evU = "PC_USERNAME"
-		evP = "PC_PASSWORD"
-	} else {
-		evU = "PE_USERNAME_" + ConvertClusterName(cluster)
-		evP = "PE_PASSWORD_" + ConvertClusterName(cluster)
+		return "PC_USERNAME", "PC_PASSWORD"
 	}
 
-	return evU, evP
+	convertedCluster := e.convertClusterName(cluster)
+	return "PE_USERNAME_" + convertedCluster, "PE_PASSWORD_" + convertedCluster
 }
 
 // getCreds reads the appropriate environment variables and returns the username and password
 // for the provided cluster name.
 //
 // If isPC is true the credentials for Prism Central will be returned, otherwise those for Prism Element.
-func getCreds(cluster string, isPC bool) (string, string, error) {
-	evU, evP := getEnvVarsForCluster(cluster, isPC)
+func (e *EnvCredentialProvider) getCreds(cluster string, isPC bool) (string, string, error) {
+	evU, evP := e.getEnvVarsForCluster(cluster, isPC)
 
 	username := os.Getenv(evU)
 	if username == "" {
@@ -73,14 +67,19 @@ func getCreds(cluster string, isPC bool) (string, string, error) {
 	return username, password, nil
 }
 
-// GetPCCreds returns the username and password for the specified Prism Central cluster
-func (evCP *EnvCredentialProvider) GetPCCreds(cluster string) (string, string, error) {
-
-	return getCreds(cluster, true)
+// GetPCCreds retrieves the username and password for a given cluster from environment variables.
+func (e *EnvCredentialProvider) GetPCCreds(cluster string) (string, string, error) {
+	return e.getCreds(cluster, true)
 }
 
-// GetPECreds returns the username and password for the specified Prism Element cluster
-func (evCP *EnvCredentialProvider) GetPECreds(cluster string) (string, string, error) {
+// GetPECreds retrieves the username and password for a given cluster from environment variables.
+func (e *EnvCredentialProvider) GetPECreds(cluster string) (string, string, error) {
+	return e.getCreds(cluster, false)
+}
 
-	return getCreds(cluster, false)
+// convertClusterName converts the cluster name to uppercase and replaces non-alphanumeric characters with underscores.
+func (e *EnvCredentialProvider) convertClusterName(cluster string) string {
+	cluster = strings.ToUpper(cluster)
+	r, _ := regexp.Compile("[^A-Z_0-9]+")
+	return r.ReplaceAllString(cluster, "_")
 }