MongoDB Go Driver: Connection Failed

In this tutorial, you'll learn about MongoDB Go Driver: Connection Failed. We cover key concepts, practical examples, and best practices.

MongoDB connection -- Connect to MongoDB using the official Go driver with a properly formatted URI.

The Problem

The MongoDB Go driver requires <a href="/databases/mongodb/">mongodb</a>://host:port format. Wrong scheme, missing auth, or wrong options cause timeout failures.

Wrong

client, err := mongo.Connect(ctx, options.Client().ApplyURI("host=localhost port=27017"))

Output:

// Connection failed: error parsing URI

Right

client, err := mongo.Connect(context.Background(),
    options.Client().ApplyURI("mongodb://localhost:27017"))
defer client.Disconnect(ctx)
err = client.Ping(ctx, readpref.Primary())

Output:

// Connected. Ping successful.

Prevention

• Use mongodb:// URI scheme
• Use mongo.Connect with ApplyURI
• Always Ping to verify
• Set connectTimeoutMS in URI
• Use context timeout for Connect

Common Mistakes with mongodb driver connect

1. Using head and tail instead of pattern matching, causing runtime errors on empty lists
2. Forgetting that lazy evaluation defers computation until the value is forced, causing space leaks with unevaluated thunks
3. Using return to exit a function early instead of wrapping a pure value in the monad

These mistakes appear frequently in real-world GO code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

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