feat(agent) multi-driver db monitoring, hot-plug config, release pipeline

internal/collectors/mongodb/mongodb.go

@@ -0,0 +1,94 @@
+package mongodb
+
+import (
+	"context"
+	"time"
+
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+
+	"bugs.watch/agent/internal/aggregate"
+)
+
+// Collector queries MongoDB serverStatus and listDatabases each sample interval.
+// All queries run under a 3-second timeout; any failure is silently skipped.
+// Metrics mapping:
+//   db_conn_pct        → current / (current + available) * 100
+//   db_threads_running → connections.current
+//   db_size_bytes      → totalSize from listDatabases
+type Collector struct {
+	client *mongo.Client
+}
+
+func New(uri string) (*Collector, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	client, err := mongo.Connect(ctx, options.Client().ApplyURI(uri).
+		SetConnectTimeout(3*time.Second).
+		SetServerSelectionTimeout(3*time.Second))
+	if err != nil {
+		return nil, err
+	}
+	return &Collector{client: client}, nil
+}
+
+func (c *Collector) Name() string { return "mongodb" }
+
+func (c *Collector) Close() {
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	c.client.Disconnect(ctx)
+}
+
+func (c *Collector) Collect(window *aggregate.Window) {
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	admin := c.client.Database("admin")
+
+	var status bson.M
+	if err := admin.RunCommand(ctx, bson.D{
+		{Key: "serverStatus", Value: 1},
+		{Key: "repl", Value: 0},
+		{Key: "metrics", Value: 0},
+		{Key: "locks", Value: 0},
+	}).Decode(&status); err != nil {
+		return
+	}
+
+	if conns, ok := status["connections"].(bson.M); ok {
+		current := toFloat64(conns["current"])
+		available := toFloat64(conns["available"])
+		total := current + available
+		if total > 0 {
+			window.AddDBConnPct(current / total * 100)
+		}
+		if current > 0 {
+			window.AddDBThreadsRunning(current)
+		}
+	}
+
+	var listResult bson.M
+	if err := admin.RunCommand(ctx, bson.D{
+		{Key: "listDatabases", Value: 1},
+		{Key: "nameOnly", Value: false},
+	}).Decode(&listResult); err == nil {
+		if totalSize := toFloat64(listResult["totalSize"]); totalSize > 0 {
+			window.SetDBSizeBytes(uint64(totalSize))
+		}
+	}
+}
+
+func toFloat64(v interface{}) float64 {
+	switch x := v.(type) {
+	case int32:
+		return float64(x)
+	case int64:
+		return float64(x)
+	case float64:
+		return x
+	}
+	return 0
+}