Fix panic when Docker is unresponsive (Issue #312)

pkg/docker/client.go

@@ -40,6 +40,14 @@ type dockerClient struct {
 	apiClient func() client.APIClient
 }
 
+func (c *dockerClient) client() (client.APIClient, error) {
+	cli := c.apiClient()
+	if cli == nil {
+		return nil, fmt.Errorf("docker client is not available. Please ensure Docker Desktop is running.")
+	}
+	return cli, nil
+}
+
 func NewClient(cli command.Cli) Client {
 	return &dockerClient{
 		apiClient: sync.OnceValue(func() client.APIClient {

pkg/docker/client_test.go

@@ -0,0 +1,28 @@
+package docker
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/docker/docker/client"
+)
+
+func TestClientSafeError(t *testing.T) {
+	// Direct initialization with a nil client factory
+	c := &dockerClient{
+		apiClient: func() client.APIClient { return nil },
+	}
+
+	// This should NOT panic anymore
+	err := c.PullImage(context.Background(), "hello-world")
+
+	if err == nil {
+		t.Fatal("Expected an error, got nil")
+	}
+
+	expectedErr := "docker client is not available"
+	if !strings.Contains(err.Error(), expectedErr) {
+		t.Errorf("Expected error to contain %q, got %q", expectedErr, err.Error())
+	}
+}

pkg/docker/containers.go

@@ -12,8 +12,12 @@ import (
 	"github.com/docker/docker/api/types/network"
 )
 
-func (c *dockerClient) ContainerExists(ctx context.Context, container string) (bool, container.InspectResponse, error) {
-	response, err := c.apiClient().ContainerInspect(ctx, container)
+func (c *dockerClient) ContainerExists(ctx context.Context, containerName string) (bool, container.InspectResponse, error) {
+	cli, err := c.client()
+	if err != nil {
+		return false, container.InspectResponse{}, err
+	}
+	response, err := cli.ContainerInspect(ctx, containerName)
 	if cerrdefs.IsNotFound(err) {
 		return false, response, nil
 	}
@@ -22,36 +26,57 @@ func (c *dockerClient) ContainerExists(ctx context.Context, container string) (b
 }
 
 func (c *dockerClient) RemoveContainer(ctx context.Context, containerID string, force bool) error {
-	return c.apiClient().ContainerRemove(ctx, containerID, container.RemoveOptions{
+	cli, err := c.client()
+	if err != nil {
+		return err
+	}
+	return cli.ContainerRemove(ctx, containerID, container.RemoveOptions{
 		Force: force,
 	})
 }
 
 func (c *dockerClient) StartContainer(ctx context.Context, containerID string, containerConfig container.Config, hostConfig container.HostConfig, networkingConfig network.NetworkingConfig) error {
-	resp, err := c.apiClient().ContainerCreate(ctx, &containerConfig, &hostConfig, &networkingConfig, nil, containerID)
+	cli, err := c.client()
+	if err != nil {
+		return err
+	}
+
+	resp, err := cli.ContainerCreate(ctx, &containerConfig, &hostConfig, &networkingConfig, nil, containerID)
 	if err != nil {
 		return fmt.Errorf("creating container: %w", err)
 	}
 
-	if err := c.apiClient().ContainerStart(ctx, resp.ID, container.StartOptions{}); err != nil {
+	if err := cli.ContainerStart(ctx, resp.ID, container.StartOptions{}); err != nil {
 		return fmt.Errorf("starting container: %w", err)
 	}
 
 	return nil
 }
 
 func (c *dockerClient) StopContainer(ctx context.Context, containerID string, timeout int) error {
-	return c.apiClient().ContainerStop(ctx, containerID, container.StopOptions{
+	cli, err := c.client()
+	if err != nil {
+		return err
+	}
+	return cli.ContainerStop(ctx, containerID, container.StopOptions{
 		Timeout: &timeout,
 	})
 }
 
 func (c *dockerClient) InspectContainer(ctx context.Context, containerID string) (container.InspectResponse, error) {
-	return c.apiClient().ContainerInspect(ctx, containerID)
+	cli, err := c.client()
+	if err != nil {
+		return container.InspectResponse{}, err
+	}
+	return cli.ContainerInspect(ctx, containerID)
 }
 
 func (c *dockerClient) FindContainerByLabel(ctx context.Context, label string) (string, error) {
-	containers, err := c.apiClient().ContainerList(ctx, container.ListOptions{
+	cli, err := c.client()
+	if err != nil {
+		return "", err
+	}
+	containers, err := cli.ContainerList(ctx, container.ListOptions{
 		Filters: filters.NewArgs(filters.Arg("label", label)),
 	})
 	if err != nil {
@@ -66,7 +91,11 @@ func (c *dockerClient) FindContainerByLabel(ctx context.Context, label string) (
 }
 
 func (c *dockerClient) FindAllContainersByLabel(ctx context.Context, label string) ([]string, error) {
-	containers, err := c.apiClient().ContainerList(ctx, container.ListOptions{
+	cli, err := c.client()
+	if err != nil {
+		return nil, err
+	}
+	containers, err := cli.ContainerList(ctx, container.ListOptions{
 		Filters: filters.NewArgs(filters.Arg("label", label)),
 	})
 	if err != nil {
@@ -92,7 +121,12 @@ func (c *dockerClient) FindAllContainersByLabel(ctx context.Context, label strin
 func (c *dockerClient) ReadLogs(ctx context.Context, containerID string, options container.LogsOptions) (io.ReadCloser, error) {
 	const streamHeaderSize = 8
 
-	rc, err := c.apiClient().ContainerLogs(ctx, containerID, options)
+	cli, err := c.client()
+	if err != nil {
+		return nil, err
+	}
+
+	rc, err := cli.ContainerLogs(ctx, containerID, options)
 	if err != nil {
 		return nil, err
 	}

pkg/docker/images.go

@@ -16,7 +16,11 @@ import (
 )
 
 func (c *dockerClient) ImageExists(ctx context.Context, name string) (bool, error) {
-	_, err := c.apiClient().ContainerInspect(ctx, name)
+	cli, err := c.client()
+	if err != nil {
+		return false, err
+	}
+	_, err = cli.ImageInspect(ctx, name)
 	if cerrdefs.IsNotFound(err) {
 		return false, nil
 	}
@@ -48,11 +52,20 @@ func (c *dockerClient) PullImage(ctx context.Context, name string) error {
 }
 
 func (c *dockerClient) InspectImage(ctx context.Context, name string) (image.InspectResponse, error) {
-	return c.apiClient().ImageInspect(ctx, name)
+	cli, err := c.client()
+	if err != nil {
+		return image.InspectResponse{}, err
+	}
+	return cli.ImageInspect(ctx, name)
 }
 
 func (c *dockerClient) pullImage(ctx context.Context, imageName string, registryAuthFn func() string) error {
-	inspect, err := c.apiClient().ImageInspect(ctx, imageName)
+	cli, err := c.client()
+	if err != nil {
+		return err
+	}
+
+	inspect, err := cli.ImageInspect(ctx, imageName)
 	if err != nil && !cerrdefs.IsNotFound(err) {
 		return fmt.Errorf("inspecting docker image %s: %w", imageName, err)
 	}
@@ -80,7 +93,7 @@ func (c *dockerClient) pullImage(ctx context.Context, imageName string, registry
 		pullOptions.RegistryAuth = registryAuthFn()
 	}
 
-	response, err := c.apiClient().ImagePull(ctx, imageName, pullOptions)
+	response, err := cli.ImagePull(ctx, imageName, pullOptions)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "  - warning: pulling docker image %s: %v", imageName, err)
 		return nil

pkg/docker/network.go

@@ -7,7 +7,11 @@ import (
 )
 
 func (c *dockerClient) CreateNetwork(ctx context.Context, name string, internal bool, labels map[string]string) error {
-	_, err := c.apiClient().NetworkCreate(ctx, name, network.CreateOptions{
+	cli, err := c.client()
+	if err != nil {
+		return err
+	}
+	_, err = cli.NetworkCreate(ctx, name, network.CreateOptions{
 		Internal: internal,
 		Labels:   labels,
 	})
@@ -19,11 +23,19 @@ func (c *dockerClient) CreateNetwork(ctx context.Context, name string, internal
 }
 
 func (c *dockerClient) RemoveNetwork(ctx context.Context, name string) error {
-	return c.apiClient().NetworkRemove(ctx, name)
+	cli, err := c.client()
+	if err != nil {
+		return err
+	}
+	return cli.NetworkRemove(ctx, name)
 }
 
 func (c *dockerClient) ConnectNetwork(ctx context.Context, networkName, container, hostname string) error {
-	return c.apiClient().NetworkConnect(ctx, networkName, container, &network.EndpointSettings{
+	cli, err := c.client()
+	if err != nil {
+		return err
+	}
+	return cli.NetworkConnect(ctx, networkName, container, &network.EndpointSettings{
 		Aliases: []string{hostname},
 	})
 }

pkg/docker/volumes.go

@@ -7,5 +7,9 @@ import (
 )
 
 func (c *dockerClient) InspectVolume(ctx context.Context, name string) (volume.Volume, error) {
-	return c.apiClient().VolumeInspect(ctx, name)
+	cli, err := c.client()
+	if err != nil {
+		return volume.Volume{}, err
+	}
+	return cli.VolumeInspect(ctx, name)
 }