Container Lifecycle Manager

A self-contained program that demonstrates full container lifecycle management using the Docker Go SDK. It pulls an nginx:alpine image, creates and starts a container, streams logs for 5 seconds, then gracefully stops and removes the container, all programmatically without the Docker CLI.

package main

import (
    "context"
    "fmt"
    "io"
    "log"
    "os"
    "time"

    "github.com/docker/docker/api/types/container"
    "github.com/docker/docker/api/types/image"
    "github.com/docker/docker/client"
    "github.com/docker/docker/pkg/stdcopy"
)

func main() {
    ctx := context.Background()

    cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
    if err != nil {
        log.Fatal(err)
    }
    defer cli.Close()

    imageName := "nginx:alpine"
    containerName := "devctl-nginx-demo"

    // Pull the image
    fmt.Printf("Pulling %s...\n", imageName)
    pullResp, err := cli.ImagePull(ctx, imageName, image.PullOptions{})
    if err != nil {
        log.Fatalf("pull: %v", err)
    }
    io.Copy(io.Discard, pullResp)
    pullResp.Close()
    fmt.Println("✓ Image pulled")

    // Create and start the container
    resp, err := cli.ContainerCreate(ctx,
        &container.Config{Image: imageName},
        nil, nil, nil, containerName,
    )
    if err != nil {
        log.Fatalf("create: %v", err)
    }
    containerID := resp.ID

    if err := cli.ContainerStart(ctx, containerID, container.StartOptions{}); err != nil {
        log.Fatalf("start: %v", err)
    }
    fmt.Printf("✓ Container %s started (ID: %s)\n", containerName, containerID[:12])

    // Stream logs for 5 seconds
    logCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
    defer cancel()

    logReader, err := cli.ContainerLogs(logCtx, containerID, container.LogsOptions{
        ShowStdout: true,
        ShowStderr: true,
        Follow:     true,
    })
    if err != nil {
        log.Printf("logs: %v", err)
    } else {
        fmt.Println("--- Container Logs ---")
        stdcopy.StdCopy(os.Stdout, os.Stderr, logReader)
        logReader.Close()
        fmt.Println("--- End Logs ---")
    }

    // Cleanup: stop and remove
    timeout := 5
    cli.ContainerStop(ctx, containerID, container.StopOptions{Timeout: &timeout})
    cli.ContainerRemove(ctx, containerID, container.RemoveOptions{Force: true})
    fmt.Printf("✓ Container %s removed\n", containerName)
}