Initial support for native docker client

This commit updates the implementation to use a native docker client as
opposed to calling an external executable.

internal/dis/component/docker/docker.go

@@ -0,0 +1,71 @@
+package docker
+
+import (
+	"context"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/dis/component"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/client"
+)
+
+type Docker struct {
+	component.Base
+}
+
+// DockerClient is a client to the docker api
+type DockerClient = *client.Client
+
+func (docker *Docker) APIClient() (DockerClient, error) {
+	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
+	if err != nil {
+		return nil, err
+	}
+	return cli, nil
+}
+
+// Ping pings the docker daemon to check if it is properly working
+func (docker *Docker) Ping(ctx context.Context) (types.Ping, error) {
+	client, err := docker.APIClient()
+	if err != nil {
+		return types.Ping{}, err
+	}
+	defer client.Close()
+
+	ping, err := client.Ping(ctx)
+	if err != nil {
+		return types.Ping{}, err
+	}
+
+	return ping, err
+}
+
+// CreateNetwork creates a docker network with the given name unless it already exists.
+// The new network will be of default type.
+// exists indicates if the network already exists.
+func (docker *Docker) CreateNetwork(ctx context.Context, name string) (id string, exists bool, err error) {
+	// create a new docker client
+	client, err := docker.APIClient()
+	if err != nil {
+		return "", false, err
+	}
+	defer client.Close()
+
+	// check if the network exists, by listing the network name
+	list, err := client.NetworkList(ctx, types.NetworkListOptions{Filters: filters.NewArgs(filters.KeyValuePair{Key: "name", Value: name})})
+	if err != nil {
+		return "", false, err
+	}
+
+	// network already exists => nothing to do
+	if len(list) == 1 {
+		return list[0].ID, true, nil
+	}
+
+	// do the actual create!
+	create, err := client.NetworkCreate(ctx, name, types.NetworkCreate{CheckDuplicate: true})
+	if err != nil {
+		return "", false, err
+	}
+	return create.ID, false, nil
+}