refactor: ♻️ ach package accepts its configuration as a parameter rather than reading from global config

pkg/metrics/README.md

@@ -7,8 +7,8 @@ A pluggable metrics collection system with Prometheus implementation.
 ```go
 import "github.com/bitechdev/ResolveSpec/pkg/metrics"
 
-// Initialize Prometheus provider
+// Initialize Prometheus provider with default config
-provider := metrics.NewPrometheusProvider()
+provider := metrics.NewPrometheusProvider(nil)
 metrics.SetProvider(provider)
 
 // Apply middleware to your router
@@ -18,6 +18,41 @@ router.Use(provider.Middleware)
 http.Handle("/metrics", provider.Handler())
 ```
 
+## Configuration
+
+You can customize the metrics provider using a configuration struct:
+
+```go
+import "github.com/bitechdev/ResolveSpec/pkg/metrics"
+
+// Create custom configuration
+config := &metrics.Config{
+    Enabled:  true,
+    Provider: "prometheus",
+    Namespace: "myapp", // Prefix all metrics with "myapp_"
+    HTTPRequestBuckets: []float64{0.01, 0.05, 0.1, 0.5, 1, 2, 5},
+    DBQueryBuckets: []float64{0.001, 0.01, 0.05, 0.1, 0.5, 1},
+}
+
+// Initialize with custom config
+provider := metrics.NewPrometheusProvider(config)
+metrics.SetProvider(provider)
+```
+
+### Configuration Options
+
+| Field | Type | Default | Description |
+|-------|------|---------|-------------|
+| `Enabled` | `bool` | `true` | Enable/disable metrics collection |
+| `Provider` | `string` | `"prometheus"` | Metrics provider type |
+| `Namespace` | `string` | `""` | Prefix for all metric names |
+| `HTTPRequestBuckets` | `[]float64` | See below | Histogram buckets for HTTP duration (seconds) |
+| `DBQueryBuckets` | `[]float64` | See below | Histogram buckets for DB query duration (seconds) |
+
+**Default HTTP Request Buckets:** `[0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10]`
+
+**Default DB Query Buckets:** `[0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5]`
+
 ## Provider Interface
 
 The package uses a provider interface, allowing you to plug in different metric systems:
@@ -87,6 +122,13 @@ When using `PrometheusProvider`, the following metrics are available:
 | `cache_hits_total` | Counter | provider | Total cache hits |
 | `cache_misses_total` | Counter | provider | Total cache misses |
 | `cache_size_items` | Gauge | provider | Current cache size |
+| `events_published_total` | Counter | source, event_type | Total events published |
+| `events_processed_total` | Counter | source, event_type, status | Total events processed |
+| `event_processing_duration_seconds` | Histogram | source, event_type | Event processing duration |
+| `event_queue_size` | Gauge | - | Current event queue size |
+| `panics_total` | Counter | method | Total panics recovered |
+
+**Note:** If a custom `Namespace` is configured, all metric names will be prefixed with `{namespace}_`.
 
 ## Prometheus Queries
 
@@ -148,6 +190,8 @@ metrics.SetProvider(&CustomProvider{})
 
 ## Complete Example
 
+### Basic Usage
+
 ```go
 package main
 
@@ -162,8 +206,8 @@ import (
 )
 
 func main() {
-    // Initialize metrics
+    // Initialize metrics with default config
-    provider := metrics.NewPrometheusProvider()
+    provider := metrics.NewPrometheusProvider(nil)
     metrics.SetProvider(provider)
 
     // Create router
@@ -198,6 +242,42 @@ func getUsersHandler(w http.ResponseWriter, r *http.Request) {
 }
 ```
 
+### With Custom Configuration
+
+```go
+package main
+
+import (
+    "log"
+    "net/http"
+
+    "github.com/bitechdev/ResolveSpec/pkg/metrics"
+    "github.com/gorilla/mux"
+)
+
+func main() {
+    // Custom metrics configuration
+    metricsConfig := &metrics.Config{
+        Enabled:  true,
+        Provider: "prometheus",
+        Namespace: "myapp",
+        // Custom buckets optimized for your application
+        HTTPRequestBuckets: []float64{0.01, 0.05, 0.1, 0.5, 1, 2, 5, 10},
+        DBQueryBuckets: []float64{0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1},
+    }
+
+    // Initialize with custom config
+    provider := metrics.NewPrometheusProvider(metricsConfig)
+    metrics.SetProvider(provider)
+
+    router := mux.NewRouter()
+    router.Use(provider.Middleware)
+    router.Handle("/metrics", provider.Handler())
+
+    log.Fatal(http.ListenAndServe(":8080", router))
+}
+```
+
 ## Docker Compose Example
 
 ```yaml

pkg/metrics/config.go

@@ -0,0 +1,46 @@
+package metrics
+
+// Config holds configuration for the metrics provider
+type Config struct {
+	// Enabled determines whether metrics collection is enabled
+	Enabled bool `mapstructure:"enabled"`
+
+	// Provider specifies which metrics provider to use (prometheus, noop)
+	Provider string `mapstructure:"provider"`
+
+	// Namespace is an optional prefix for all metric names
+	Namespace string `mapstructure:"namespace"`
+
+	// HTTPRequestBuckets defines histogram buckets for HTTP request duration (in seconds)
+	// Default: [0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10]
+	HTTPRequestBuckets []float64 `mapstructure:"http_request_buckets"`
+
+	// DBQueryBuckets defines histogram buckets for database query duration (in seconds)
+	// Default: [0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5]
+	DBQueryBuckets []float64 `mapstructure:"db_query_buckets"`
+}
+
+// DefaultConfig returns a Config with sensible defaults
+func DefaultConfig() *Config {
+	return &Config{
+		Enabled:  true,
+		Provider: "prometheus",
+		// HTTP requests typically take longer than DB queries
+		HTTPRequestBuckets: []float64{0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10},
+		// DB queries are usually faster
+		DBQueryBuckets: []float64{0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5},
+	}
+}
+
+// ApplyDefaults fills in any missing values with defaults
+func (c *Config) ApplyDefaults() {
+	if c.Provider == "" {
+		c.Provider = "prometheus"
+	}
+	if len(c.HTTPRequestBuckets) == 0 {
+		c.HTTPRequestBuckets = []float64{0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10}
+	}
+	if len(c.DBQueryBuckets) == 0 {
+		c.DBQueryBuckets = []float64{0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5}
+	}
+}

pkg/metrics/example_test.go

@@ -0,0 +1,64 @@
+package metrics_test
+
+import (
+	"fmt"
+
+	"github.com/bitechdev/ResolveSpec/pkg/metrics"
+)
+
+// ExampleNewPrometheusProvider_default demonstrates using default configuration
+func ExampleNewPrometheusProvider_default() {
+	// Initialize with default configuration
+	provider := metrics.NewPrometheusProvider(nil)
+	metrics.SetProvider(provider)
+
+	fmt.Println("Provider initialized with defaults")
+	// Output: Provider initialized with defaults
+}
+
+// ExampleNewPrometheusProvider_custom demonstrates using custom configuration
+func ExampleNewPrometheusProvider_custom() {
+	// Create custom configuration
+	config := &metrics.Config{
+		Enabled:            true,
+		Provider:           "prometheus",
+		Namespace:          "myapp",
+		HTTPRequestBuckets: []float64{0.01, 0.05, 0.1, 0.5, 1, 2, 5},
+		DBQueryBuckets:     []float64{0.001, 0.01, 0.05, 0.1, 0.5, 1},
+	}
+
+	// Initialize with custom configuration
+	provider := metrics.NewPrometheusProvider(config)
+	metrics.SetProvider(provider)
+
+	fmt.Println("Provider initialized with custom config")
+	// Output: Provider initialized with custom config
+}
+
+// ExampleDefaultConfig demonstrates getting default configuration
+func ExampleDefaultConfig() {
+	config := metrics.DefaultConfig()
+	fmt.Printf("Default provider: %s\n", config.Provider)
+	fmt.Printf("Default enabled: %v\n", config.Enabled)
+	// Output:
+	// Default provider: prometheus
+	// Default enabled: true
+}
+
+// ExampleConfig_ApplyDefaults demonstrates applying defaults to partial config
+func ExampleConfig_ApplyDefaults() {
+	// Create partial configuration
+	config := &metrics.Config{
+		Namespace: "myapp",
+		// Other fields will be filled with defaults
+	}
+
+	// Apply defaults
+	config.ApplyDefaults()
+
+	fmt.Printf("Provider: %s\n", config.Provider)
+	fmt.Printf("Namespace: %s\n", config.Namespace)
+	// Output:
+	// Provider: prometheus
+	// Namespace: myapp
+}

pkg/metrics/prometheus.go

@@ -20,23 +20,44 @@ type PrometheusProvider struct {
 	cacheHits        *prometheus.CounterVec
 	cacheMisses      *prometheus.CounterVec
 	cacheSize        *prometheus.GaugeVec
+	eventPublished   *prometheus.CounterVec
+	eventProcessed   *prometheus.CounterVec
+	eventDuration    *prometheus.HistogramVec
+	eventQueueSize   prometheus.Gauge
 	panicsTotal      *prometheus.CounterVec
 }
 
 // NewPrometheusProvider creates a new Prometheus metrics provider
-func NewPrometheusProvider() *PrometheusProvider {
+// If cfg is nil, default configuration will be used
+func NewPrometheusProvider(cfg *Config) *PrometheusProvider {
+	// Use default config if none provided
+	if cfg == nil {
+		cfg = DefaultConfig()
+	} else {
+		// Apply defaults for any missing values
+		cfg.ApplyDefaults()
+	}
+
+	// Helper to add namespace prefix if configured
+	metricName := func(name string) string {
+		if cfg.Namespace != "" {
+			return cfg.Namespace + "_" + name
+		}
+		return name
+	}
+
 	return &PrometheusProvider{
 		requestDuration: promauto.NewHistogramVec(
 			prometheus.HistogramOpts{
-				Name:    "http_request_duration_seconds",
+				Name:    metricName("http_request_duration_seconds"),
 				Help:    "HTTP request duration in seconds",
-				Buckets: prometheus.DefBuckets,
+				Buckets: cfg.HTTPRequestBuckets,
 			},
 			[]string{"method", "path", "status"},
 		),
 		requestTotal: promauto.NewCounterVec(
 			prometheus.CounterOpts{
-				Name: "http_requests_total",
+				Name: metricName("http_requests_total"),
 				Help: "Total number of HTTP requests",
 			},
 			[]string{"method", "path", "status"},
@@ -44,49 +65,77 @@ func NewPrometheusProvider() *PrometheusProvider {
 
 		requestsInFlight: promauto.NewGauge(
 			prometheus.GaugeOpts{
-				Name: "http_requests_in_flight",
+				Name: metricName("http_requests_in_flight"),
 				Help: "Current number of HTTP requests being processed",
 			},
 		),
 		dbQueryDuration: promauto.NewHistogramVec(
 			prometheus.HistogramOpts{
-				Name:    "db_query_duration_seconds",
+				Name:    metricName("db_query_duration_seconds"),
 				Help:    "Database query duration in seconds",
-				Buckets: prometheus.DefBuckets,
+				Buckets: cfg.DBQueryBuckets,
 			},
 			[]string{"operation", "table"},
 		),
 		dbQueryTotal: promauto.NewCounterVec(
 			prometheus.CounterOpts{
-				Name: "db_queries_total",
+				Name: metricName("db_queries_total"),
 				Help: "Total number of database queries",
 			},
 			[]string{"operation", "table", "status"},
 		),
 		cacheHits: promauto.NewCounterVec(
 			prometheus.CounterOpts{
-				Name: "cache_hits_total",
+				Name: metricName("cache_hits_total"),
 				Help: "Total number of cache hits",
 			},
 			[]string{"provider"},
 		),
 		cacheMisses: promauto.NewCounterVec(
 			prometheus.CounterOpts{
-				Name: "cache_misses_total",
+				Name: metricName("cache_misses_total"),
 				Help: "Total number of cache misses",
 			},
 			[]string{"provider"},
 		),
 		cacheSize: promauto.NewGaugeVec(
 			prometheus.GaugeOpts{
-				Name: "cache_size_items",
+				Name: metricName("cache_size_items"),
 				Help: "Number of items in cache",
 			},
 			[]string{"provider"},
 		),
+		eventPublished: promauto.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: metricName("events_published_total"),
+				Help: "Total number of events published",
+			},
+			[]string{"source", "event_type"},
+		),
+		eventProcessed: promauto.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: metricName("events_processed_total"),
+				Help: "Total number of events processed",
+			},
+			[]string{"source", "event_type", "status"},
+		),
+		eventDuration: promauto.NewHistogramVec(
+			prometheus.HistogramOpts{
+				Name:    metricName("event_processing_duration_seconds"),
+				Help:    "Event processing duration in seconds",
+				Buckets: cfg.DBQueryBuckets, // Events are typically fast like DB queries
+			},
+			[]string{"source", "event_type"},
+		),
+		eventQueueSize: promauto.NewGauge(
+			prometheus.GaugeOpts{
+				Name: metricName("event_queue_size"),
+				Help: "Current number of events in queue",
+			},
+		),
 		panicsTotal: promauto.NewCounterVec(
 			prometheus.CounterOpts{
-				Name: "panics_total",
+				Name: metricName("panics_total"),
 				Help: "Total number of panics",
 			},
 			[]string{"method"},
@@ -153,6 +202,22 @@ func (p *PrometheusProvider) UpdateCacheSize(provider string, size int64) {
 	p.cacheSize.WithLabelValues(provider).Set(float64(size))
 }
 
+// RecordEventPublished implements Provider interface
+func (p *PrometheusProvider) RecordEventPublished(source, eventType string) {
+	p.eventPublished.WithLabelValues(source, eventType).Inc()
+}
+
+// RecordEventProcessed implements Provider interface
+func (p *PrometheusProvider) RecordEventProcessed(source, eventType, status string, duration time.Duration) {
+	p.eventProcessed.WithLabelValues(source, eventType, status).Inc()
+	p.eventDuration.WithLabelValues(source, eventType).Observe(duration.Seconds())
+}
+
+// UpdateEventQueueSize implements Provider interface
+func (p *PrometheusProvider) UpdateEventQueueSize(size int64) {
+	p.eventQueueSize.Set(float64(size))
+}
+
 // RecordPanic implements the Provider interface
 func (p *PrometheusProvider) RecordPanic(methodName string) {
 	p.panicsTotal.WithLabelValues(methodName).Inc()