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

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}
+	}
+}