Add export and load for dagger images

Signed-off-by: Helder Correia <174525+helderco@users.noreply.github.com>

pkg/universe.dagger.io/docker/load.cue

@@ -0,0 +1,112 @@
+package docker
+
+import (
+	"dagger.io/dagger"
+)
+
+// Load an image into a docker daemon
+#Load: {
+	// Image to load
+	image: #Image
+
+	// Name and optionally a tag in the 'name:tag' format
+	tag: #Ref
+
+	// Exported image ID
+	imageID: _export.imageID
+
+	// Root filesystem with exported file
+	result: _export.output
+
+	_export: dagger.#Export & {
+		"tag":  tag
+		input:  image.rootfs
+		config: image.config
+	}
+
+	#_cli & {
+		mounts: src: {
+			dest:     "/src"
+			contents: _export.output
+		}
+		command: {
+			name: "load"
+			flags: "-i": "/src/image.tar"
+		}
+	}
+}
+
+// FIXME: Move this into docker/client or
+// create a better abstraction to reuse here.
+#_cli: {
+	#_socketConn | #_sshConn | #_tcpConn
+
+	_image: #Pull & {
+		source: "docker:20.10.13-alpine3.15"
+	}
+
+	input: _image.output
+}
+
+// Connect via local docker socket
+#_socketConn: {
+	host: dagger.#Service
+
+	#Run & {
+		mounts: docker: {
+			dest:     "/var/run/docker.sock"
+			contents: host
+		}
+	}
+}
+
+// Connect via HTTP/HTTPS
+#_tcpConn: {
+	host: =~"^tcp://.+"
+
+	#Run & {
+		env: DOCKER_HOST: host
+
+		// Directory with certificates to verify ({ca,cert,key}.pem files).
+		// This enables HTTPS.
+		certs?: dagger.#FS
+
+		if certs != _|_ {
+			mounts: "certs": {
+				dest:     "/certs/client"
+				contents: certs
+			}
+		}
+	}
+}
+
+// Connect via SSH
+#_sshConn: {
+	host: =~"^ssh://.+"
+
+	ssh: {
+		// Private SSH key
+		key?: dagger.#Secret
+
+		// Known hosts file contents
+		knownHosts?: dagger.#Secret
+	}
+
+	#Run & {
+		env: DOCKER_HOST: host
+
+		if ssh.key != _|_ {
+			mounts: ssh_key: {
+				dest:     "/root/.ssh/id_rsa"
+				contents: ssh.key
+			}
+		}
+
+		if ssh.knownHosts != _|_ {
+			mounts: ssh_hosts: {
+				dest:     "/root/.ssh/known_hosts"
+				contents: ssh.knownHosts
+			}
+		}
+	}
+}