Error handling

Introduction

In production applications, proper error handling is crucial for maintaining system stability and providing meaningful feedback to users.

The Neo4j Go driver provides comprehensive error handling capabilities that help you manage different types of errors gracefully.

Types of errors

Neo4j errors can be categorized into several types:

Connection errors - Network issues, authentication failures
Constraint errors - Violations of database constraints
Transaction errors - Deadlocks, timeout issues
Query errors - Syntax errors, parameter issues

import (
    "errors"
    "github.com/neo4j/neo4j-go-driver/v5/neo4j"
)

result, err := neo4j.ExecuteQuery(ctx, driver, query, params, neo4j.EagerResultTransformer)
if err != nil {
    // Check for specific error types
    if neo4j.IsNeo4jError(err) {
        neo4jErr := err.(*neo4j.Neo4jError)
        switch neo4jErr.Code {
        case "Neo.ClientError.Schema.ConstraintValidationFailed":
            // Handle constraint violation
            log.Printf("Constraint violation: %s", neo4jErr.Msg)
        case "Neo.ClientError.Statement.SyntaxError":
            // Handle syntax error
            log.Printf("Syntax error: %s", neo4jErr.Msg)
        default:
            // Handle other Neo4j errors
            log.Printf("Neo4j error: %s", neo4jErr.Msg)
        }
    } else {
        // Handle non-Neo4j errors
        log.Printf("Other error: %v", err)
    }
}

Retry logic

For transient errors, you can implement retry logic:

func executeWithRetry(ctx context.Context, driver neo4j.Driver, query string, params map[string]any, maxRetries int) (neo4j.EagerResult, error) {
    var lastErr error

    for i := 0; i < maxRetries; i++ {
        result, err := neo4j.ExecuteQuery(ctx, driver, query, params, neo4j.EagerResultTransformer)
        if err == nil {
            return result, nil
        }

        // Check if error is retryable
        if neo4j.IsRetryable(err) {
            lastErr = err
            time.Sleep(time.Duration(i+1) * time.Second) // Exponential backoff
            continue
        }

        // Non-retryable error
        return neo4j.EagerResult{}, err
    }

    return neo4j.EagerResult{}, lastErr
}

Check your understanding

Advance to challenge

Summary

In this lesson, you learned about error handling in Neo4j applications using the Go driver.

Proper error handling ensures your application can gracefully handle various error conditions and provide meaningful feedback to users.

Using Neo4j with Go

The Driver

Handling results

Best practices