feat(packages): ✨ Prometheus publish events

pkg/metrics/README.md

@@ -53,6 +53,24 @@ metrics.SetProvider(provider)
 
 **Default DB Query Buckets:** `[0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5]`
 
+### Pushgateway Configuration (Optional)
+
+For batch jobs, cron tasks, or short-lived processes, you can push metrics to Prometheus Pushgateway:
+
+| Field | Type | Default | Description |
+|-------|------|---------|-------------|
+| `PushgatewayURL` | `string` | `""` | URL of Pushgateway (e.g., "http://pushgateway:9091") |
+| `PushgatewayJobName` | `string` | `"resolvespec"` | Job name for pushed metrics |
+| `PushgatewayInterval` | `int` | `0` | Auto-push interval in seconds (0 = disabled) |
+
+```go
+config := &metrics.Config{
+    PushgatewayURL:      "http://pushgateway:9091",
+    PushgatewayJobName:  "batch-job",
+    PushgatewayInterval: 30, // Push every 30 seconds
+}
+```
+
 ## Provider Interface
 
 The package uses a provider interface, allowing you to plug in different metric systems:
@@ -188,6 +206,122 @@ func (c *CustomProvider) Handler() http.Handler {
 metrics.SetProvider(&CustomProvider{})
 ```
 
+## Pushgateway Usage
+
+### Automatic Push (Batch Jobs)
+
+For jobs that run periodically, use automatic pushing:
+
+```go
+package main
+
+import (
+    "time"
+
+    "github.com/bitechdev/ResolveSpec/pkg/metrics"
+)
+
+func main() {
+    // Configure with automatic pushing every 30 seconds
+    config := &metrics.Config{
+        Enabled:             true,
+        Provider:            "prometheus",
+        Namespace:           "batch_job",
+        PushgatewayURL:      "http://pushgateway:9091",
+        PushgatewayJobName:  "data-processor",
+        PushgatewayInterval: 30, // Push every 30 seconds
+    }
+
+    provider := metrics.NewPrometheusProvider(config)
+    metrics.SetProvider(provider)
+
+    // Ensure cleanup on exit
+    defer provider.StopAutoPush()
+
+    // Your batch job logic here
+    processBatchData()
+}
+```
+
+### Manual Push (Short-lived Processes)
+
+For one-time jobs or when you want manual control:
+
+```go
+package main
+
+import (
+    "log"
+
+    "github.com/bitechdev/ResolveSpec/pkg/metrics"
+)
+
+func main() {
+    // Configure without automatic pushing
+    config := &metrics.Config{
+        Enabled:            true,
+        Provider:           "prometheus",
+        PushgatewayURL:     "http://pushgateway:9091",
+        PushgatewayJobName: "migration-job",
+        // PushgatewayInterval: 0 (default - no auto-push)
+    }
+
+    provider := metrics.NewPrometheusProvider(config)
+    metrics.SetProvider(provider)
+
+    // Run your job
+    err := runMigration()
+
+    // Push metrics at the end
+    if pushErr := provider.Push(); pushErr != nil {
+        log.Printf("Failed to push metrics: %v", pushErr)
+    }
+
+    if err != nil {
+        log.Fatal(err)
+    }
+}
+```
+
+### Docker Compose with Pushgateway
+
+```yaml
+version: '3'
+services:
+  batch-job:
+    build: .
+    environment:
+      PUSHGATEWAY_URL: "http://pushgateway:9091"
+
+  pushgateway:
+    image: prom/pushgateway
+    ports:
+      - "9091:9091"
+
+  prometheus:
+    image: prom/prometheus
+    ports:
+      - "9090:9090"
+    volumes:
+      - ./prometheus.yml:/etc/prometheus/prometheus.yml
+    command:
+      - '--config.file=/etc/prometheus/prometheus.yml'
+```
+
+**prometheus.yml for Pushgateway:**
+
+```yaml
+global:
+  scrape_interval: 15s
+
+scrape_configs:
+  # Scrape the pushgateway
+  - job_name: 'pushgateway'
+    honor_labels: true  # Important: preserve job labels from pushed metrics
+    static_configs:
+      - targets: ['pushgateway:9091']
+```
+
 ## Complete Example
 
 ### Basic Usage
@@ -337,3 +471,8 @@ scrape_configs:
 4. **Performance**: Metrics collection is lock-free and highly performant
    - Safe for high-throughput applications
    - Minimal overhead (<1% in most cases)
+
+5. **Pull vs Push**:
+   - **Use Pull (default)**: Long-running services, web servers, microservices
+   - **Use Push (Pushgateway)**: Batch jobs, cron tasks, short-lived processes, serverless functions
+   - Pull is preferred for most applications as it allows Prometheus to detect if your service is down

pkg/metrics/config.go

@@ -18,6 +18,20 @@ type Config struct {
 	// 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"`
+
+	// PushgatewayURL is the URL of the Prometheus Pushgateway (optional)
+	// If set, metrics will be pushed to this gateway instead of only being scraped
+	// Example: "http://pushgateway:9091"
+	PushgatewayURL string `mapstructure:"pushgateway_url"`
+
+	// PushgatewayJobName is the job name to use when pushing metrics to Pushgateway
+	// Default: "resolvespec"
+	PushgatewayJobName string `mapstructure:"pushgateway_job_name"`
+
+	// PushgatewayInterval is the interval at which to push metrics to Pushgateway
+	// Only used if PushgatewayURL is set. If 0, automatic pushing is disabled.
+	// Default: 0 (no automatic pushing)
+	PushgatewayInterval int `mapstructure:"pushgateway_interval"`
 }
 
 // DefaultConfig returns a Config with sensible defaults
@@ -43,4 +57,8 @@ func (c *Config) ApplyDefaults() {
 	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}
 	}
+	// Set default job name if pushgateway is configured but job name is empty
+	if c.PushgatewayURL != "" && c.PushgatewayJobName == "" {
+		c.PushgatewayJobName = "resolvespec"
+	}
 }

pkg/metrics/prometheus.go

@@ -8,6 +8,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/prometheus/client_golang/prometheus/push"
 )
 
 // PrometheusProvider implements the Provider interface using Prometheus
@@ -25,6 +26,13 @@ type PrometheusProvider struct {
 	eventDuration    *prometheus.HistogramVec
 	eventQueueSize   prometheus.Gauge
 	panicsTotal      *prometheus.CounterVec
+
+	// Pushgateway fields (optional)
+	pushgatewayURL     string
+	pushgatewayJobName string
+	pusher             *push.Pusher
+	pushTicker         *time.Ticker
+	pushStop           chan bool
 }
 
 // NewPrometheusProvider creates a new Prometheus metrics provider
@@ -46,7 +54,7 @@ func NewPrometheusProvider(cfg *Config) *PrometheusProvider {
 		return name
 	}
 
-	return &PrometheusProvider{
+	p := &PrometheusProvider{
 		requestDuration: promauto.NewHistogramVec(
 			prometheus.HistogramOpts{
 				Name:    metricName("http_request_duration_seconds"),
@@ -140,7 +148,25 @@ func NewPrometheusProvider(cfg *Config) *PrometheusProvider {
 			},
 			[]string{"method"},
 		),
+
+		pushgatewayURL:     cfg.PushgatewayURL,
+		pushgatewayJobName: cfg.PushgatewayJobName,
 	}
+
+	// Initialize pushgateway if configured
+	if cfg.PushgatewayURL != "" {
+		p.pusher = push.New(cfg.PushgatewayURL, cfg.PushgatewayJobName).
+			Gatherer(prometheus.DefaultGatherer)
+
+		// Start automatic pushing if interval is configured
+		if cfg.PushgatewayInterval > 0 {
+			p.pushStop = make(chan bool)
+			p.pushTicker = time.NewTicker(time.Duration(cfg.PushgatewayInterval) * time.Second)
+			go p.startAutoPush()
+		}
+	}
+
+	return p
 }
 
 // ResponseWriter wraps http.ResponseWriter to capture status code
@@ -250,3 +276,37 @@ func (p *PrometheusProvider) Middleware(next http.Handler) http.Handler {
 		p.RecordHTTPRequest(r.Method, r.URL.Path, status, duration)
 	})
 }
+
+// Push manually pushes metrics to the configured Pushgateway
+// Returns an error if pushing fails or if Pushgateway is not configured
+func (p *PrometheusProvider) Push() error {
+	if p.pusher == nil {
+		return nil // Pushgateway not configured, silently skip
+	}
+	return p.pusher.Push()
+}
+
+// startAutoPush runs in a goroutine and periodically pushes metrics to Pushgateway
+func (p *PrometheusProvider) startAutoPush() {
+	for {
+		select {
+		case <-p.pushTicker.C:
+			if err := p.Push(); err != nil {
+				// Log error but continue pushing
+				// Note: In production, you might want to use a proper logger
+				_ = err
+			}
+		case <-p.pushStop:
+			p.pushTicker.Stop()
+			return
+		}
+	}
+}
+
+// StopAutoPush stops the automatic push goroutine
+// This should be called when shutting down the application
+func (p *PrometheusProvider) StopAutoPush() {
+	if p.pushStop != nil {
+		close(p.pushStop)
+	}
+}