refactor: use pkg directory structure

pkg/client/client.go

@@ -0,0 +1,52 @@
+// Package client provides Docker client initiatialisation functions.
+package client
+
+import (
+	"net/http"
+	"os"
+
+	"github.com/docker/docker/client"
+	"github.com/sirupsen/logrus"
+)
+
+// New initiates a new Docker client.
+func New(contextName string) (*client.Client, error) {
+	context, err := GetContext(contextName)
+	if err != nil {
+		return nil, err
+	}
+
+	ctxEndpoint, err := GetContextEndpoint(context)
+	if err != nil {
+		return nil, err
+	}
+
+	helper := newConnectionHelper(ctxEndpoint)
+	httpClient := &http.Client{
+		// No tls, no proxy
+		Transport: &http.Transport{
+			DialContext: helper.Dialer,
+		},
+	}
+
+	var clientOpts []client.Opt
+	clientOpts = append(clientOpts,
+		client.WithHTTPClient(httpClient),
+		client.WithHost(helper.Host),
+		client.WithDialContext(helper.Dialer),
+	)
+
+	version := os.Getenv("DOCKER_API_VERSION")
+	if version != "" {
+		clientOpts = append(clientOpts, client.WithVersion(version))
+	} else {
+		clientOpts = append(clientOpts, client.WithAPIVersionNegotiation())
+	}
+
+	cl, err := client.NewClientWithOpts(clientOpts...)
+	if err != nil {
+		logrus.Fatalf("unable to create Docker client: %s", err)
+	}
+
+	return cl, nil
+}