MongoDB

Use the Last9 Go Agent to instrument MongoDB operations with automatic tracing and metrics. All CRUD operations, aggregation pipelines, and index operations are traced. Connection housekeeping commands (hello, ping, isMaster) and auth handshakes are silently skipped.

Prerequisites

Go 1.22 or higher
MongoDB Go driver v1 (go.mongodb.org/mongo-driver)
Last9 account with OTLP credentials

Installation

Install the Last9 Go Agent
```
go get github.com/last9/go-agent
```

Set Environment Variables

export OTEL_SERVICE_NAME="your-service"
export OTEL_EXPORTER_OTLP_ENDPOINT="$last9_otlp_endpoint"
export OTEL_EXPORTER_OTLP_HEADERS="Authorization=$last9_otlp_auth_header"
export OTEL_TRACES_SAMPLER="always_on"
export OTEL_RESOURCE_ATTRIBUTES="deployment.environment=production"

Instrument your application

New client
Existing client options

Use mongoagent.NewClient() instead of mongo.Connect():

package main

import (
    "context"
    "log"

    "go.mongodb.org/mongo-driver/bson"
    "github.com/last9/go-agent"
    mongoagent "github.com/last9/go-agent/integrations/mongodb"
)

func main() {
    if err := agent.Start(); err != nil {
        log.Fatalf("failed to start agent: %v", err)
    }
    defer agent.Shutdown()

    client, err := mongoagent.NewClient(mongoagent.Config{
        URI: "mongodb://localhost:27017",
    })
    if err != nil {
        log.Fatal(err)
    }
    defer client.Disconnect(context.Background())

    col := client.Database("mydb").Collection("users")

    // All operations are automatically traced
    _, err = col.InsertOne(context.Background(), bson.M{"name": "Alice", "age": 30})
    if err != nil {
        log.Fatal(err)
    }

    var result bson.M
    err = col.FindOne(context.Background(), bson.M{"name": "Alice"}).Decode(&result)
    if err != nil {
        log.Fatal(err)
    }

    log.Printf("found: %v", result)
}

Instrument an existing *options.ClientOptions — useful when you already have connection options configured:

package main

import (
    "context"
    "log"
    "os"

    "go.mongodb.org/mongo-driver/mongo/options"
    "github.com/last9/go-agent"
    mongoagent "github.com/last9/go-agent/integrations/mongodb"
)

func main() {
    if err := agent.Start(); err != nil {
        log.Fatalf("failed to start agent: %v", err)
    }
    defer agent.Shutdown()

    opts := options.Client().ApplyURI(os.Getenv("MONGO_URI"))
    opts.SetAuth(options.Credential{
        Username: "admin",
        Password: os.Getenv("MONGO_PASSWORD"),
    })

    // Instrument the options — returns a fully connected client
    client, err := mongoagent.Instrument(opts)
    if err != nil {
        log.Fatal(err)
    }
    defer client.Disconnect(context.Background())

    col := client.Database("mydb").Collection("orders")
    // All operations are automatically traced
}

What Gets Traced

All CRUD operations are traced automatically:

col := client.Database("mydb").Collection("products")
ctx := context.Background()

// All of these produce spans:
col.InsertOne(ctx, bson.M{"name": "Widget", "price": 9.99})
col.InsertMany(ctx, []interface{}{bson.M{"name": "A"}, bson.M{"name": "B"}})
col.Find(ctx, bson.M{"price": bson.M{"$gt": 5.0}})
col.FindOne(ctx, bson.M{"_id": id})
col.UpdateOne(ctx, bson.M{"_id": id}, bson.M{"$set": bson.M{"price": 12.99}})
col.DeleteOne(ctx, bson.M{"_id": id})
col.Aggregate(ctx, mongo.Pipeline{...})
col.Indexes().CreateOne(ctx, mongo.IndexModel{...})

Commands that are skipped (noise reduction):

hello, isMaster, ping — connection housekeeping
saslStart, saslContinue, authenticate — auth handshakes
endSessions

Span Attributes

Each traced operation includes:

Attribute	Example
`db.system`	`mongodb`
`db.name`	`mydb`
`db.operation`	`find`, `insert`, `update`
`db.mongodb.collection`	`users`
`db.statement`	sanitized command document
`server.address`	`localhost`
`server.port`	`27017`

What Gets Measured Automatically

Metric	Description
`db.mongodb.operations`	Total operation count by operation type
`db.mongodb.errors`	Failed operation count
`db.mongodb.operation.duration`	Duration histogram in milliseconds

View Traces and Metrics

After running your application, navigate to Trace Explorer and Metrics Explorer in Last9 to view your telemetry data.

Troubleshooting

Please get in touch with us on Discord or Email if you have any questions.