container-manager

Author: gauravgahlot

internal/container-manager/container_manager.go

@@ -0,0 +1,132 @@
+package containermanager
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+
+	api "github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/client"
+	"github.com/dockersamples/gopher-task-system/internal/types"
+	"github.com/pkg/errors"
+)
+
+type ContainerManager interface {
+	PullImage(ctx context.Context, image string) error
+	CreateContainer(ctx context.Context, task types.Task) (string, error)
+	StartContainer(ctx context.Context, id string) error
+	WaitForContainer(ctx context.Context, id string) (bool, error)
+	RemoveContainer(ctx context.Context, id string) error
+}
+
+type DockerClient interface {
+	client.ImageAPIClient
+	client.ContainerAPIClient
+}
+
+type ImagePullStatus struct {
+	Status         string `json:"status"`
+	Error          string `json:"error"`
+	Progress       string `json:"progress"`
+	ProgressDetail struct {
+		Current int `json:"current"`
+		Total   int `json:"total"`
+	} `json:"progressDetail"`
+}
+
+type containermanager struct {
+	cli DockerClient
+}
+
+func NewContainerManager(cli DockerClient) ContainerManager {
+	return &containermanager{
+		cli: cli,
+	}
+}
+
+// PullImage outputs to stdout the contents of the runner image.
+func (m *containermanager) PullImage(ctx context.Context, image string) error {
+	out, err := m.cli.ImagePull(ctx, image, api.ImagePullOptions{})
+	if err != nil {
+		return errors.Wrap(err, "DOCKER PULL")
+	}
+
+	defer func() {
+		if err := out.Close(); err != nil {
+			fmt.Println(err)
+		}
+	}()
+
+	fd := json.NewDecoder(out)
+	var status *ImagePullStatus
+	for {
+		if err := fd.Decode(&status); err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+
+			return errors.Wrap(err, "DOCKER PULL")
+		}
+
+		if status.Error != "" {
+			return errors.Wrap(errors.New(status.Error), "DOCKER PULL")
+		}
+
+		// uncomment to log image pull status
+		// fmt.Println(status)
+	}
+
+	return nil
+}
+
+// CreateContainer creates a new container and returns it ID.
+func (m *containermanager) CreateContainer(ctx context.Context, task types.Task) (string, error) {
+	config := &container.Config{
+		Image: task.Runner,
+		Cmd:   task.Command,
+	}
+
+	res, err := m.cli.ContainerCreate(ctx, config, &container.HostConfig{}, nil, nil, task.Name)
+	if err != nil {
+		return "", err
+	}
+
+	return res.ID, nil
+}
+
+// StartContainer starts the container created with given ID.
+func (m *containermanager) StartContainer(ctx context.Context, id string) error {
+	return m.cli.ContainerStart(ctx, id, api.ContainerStartOptions{})
+}
+
+// WaitForContainer waits for the running container to finish.
+func (m *containermanager) WaitForContainer(ctx context.Context, id string) (bool, error) {
+	// check if the container is in running state
+	if _, err := m.cli.ContainerInspect(ctx, id); err != nil {
+		return true, nil
+	}
+
+	// send API call to wait for the container completion
+	wait, errC := m.cli.ContainerWait(ctx, id, container.WaitConditionNotRunning)
+
+	// check if container exit code is 0, and return accordingly
+	select {
+	case status := <-wait:
+		if status.StatusCode == 0 {
+			return true, nil
+		}
+
+		return false, nil
+	case err := <-errC:
+		return false, err
+	case <-ctx.Done():
+		return false, ctx.Err()
+	}
+}
+
+// RemoveContainer removes the given container../0+
+func (m *containermanager) RemoveContainer(ctx context.Context, id string) error {
+	return m.cli.ContainerRemove(ctx, id, api.ContainerRemoveOptions{})
+}