What problems did you encounter during product deployment and how did you try to prevent them in the future?

When deploying a product, I often encountered the following issues:

• Unexpected errors in production due to differences between development and production environments.
• Long downtime during updates due to lack of automation and rollback capabilities.
• Database migration problems, leading to data loss or inconsistency.
• Incomplete integration testing, causing service failures.

To prevent such problems, the following practices were applied:

• CI/CD pipelines for automating build, testing, and deployment, reducing human error and speeding up the process.
• Containerization (Docker) to standardize environments and eliminate differences between environments.
• Blue-Green and Canary deployments to minimize downtime and enable quick rollbacks in case of errors.
• Automated database migrations with rollback options.
• Monitoring and logging for quick detection and response to issues.

Example of a simple deployment script with rollback in Go:

package main

import (
    "fmt"
    "os/exec"
)

func deploy() error {
    // Build
    if err := exec.Command("go", "build", "-o", "app").Run(); err != nil {
        return err
    }
    // Stop current service
    if err := exec.Command("systemctl", "stop", "myapp").Run(); err != nil {
        return err
    }
    // Start new service
    if err := exec.Command("systemctl", "start", "myapp").Run(); err != nil {
        // On error, start old version
        exec.Command("systemctl", "start", "myapp").Run()
        return err
    }
    return nil
}

func main() {
    if err := deploy(); err != nil {
        fmt.Println("Deployment failed:", err)
    } else {
        fmt.Println("Deployment succeeded")
    }
}