introduce first docker plugin

e2e/docker-compose.yml

@@ -7,6 +7,10 @@ services:
       - PASSWORD_ACCESS=true
       - USER_PASSWORD=pass
       - USER_NAME=user
+    labels:
+      - sshpiper.username=pass
+      - sshpiper.container_username=user
+      - sshpiper.port=2222
     volumes:
       - shared:/shared
       - sshconfig_password:/config
@@ -32,7 +36,9 @@ services:
       - shared:/shared
       - sshconfig_publickey:/sshconfig_publickey
       - sshconfig_password:/sshconfig_password
+      - /var/run/docker.sock:/var/run/docker.sock
     command: ["./e2eentry.sh"]
+    privileged: true
     working_dir: /src/e2e
     depends_on:
       - host-publickey

e2e/docker_test.go

@@ -0,0 +1,57 @@
+package e2e_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+func TestDocker(t *testing.T) {
+	piperaddr, piperport := nextAvailablePiperAddress()
+
+	piper, _, _, err := runCmd("/sshpiperd/sshpiperd",
+		"-p",
+		piperport,
+		"/sshpiperd/plugins/docker",
+	)
+
+	if err != nil {
+		t.Errorf("failed to run sshpiperd: %v", err)
+	}
+
+	defer killCmd(piper)
+
+	waitForEndpointReady(piperaddr)
+
+	randtext := uuid.New().String()
+	targetfie := uuid.New().String()
+
+	c, stdin, stdout, err := runCmd(
+		"ssh",
+		"-v",
+		"-o",
+		"StrictHostKeyChecking=no",
+		"-o",
+		"UserKnownHostsFile=/dev/null",
+		"-p",
+		piperport,
+		"-l",
+		"pass",
+		"127.0.0.1",
+		fmt.Sprintf(`sh -c "echo -n %v > /shared/%v"`, randtext, targetfie),
+	)
+
+	if err != nil {
+		t.Errorf("failed to ssh to piper-fixed, %v", err)
+	}
+
+	defer killCmd(c)
+
+	enterPassword(stdin, stdout, "pass")
+
+	time.Sleep(time.Second) // wait for file flush
+
+	checkSharedFileContent(t, targetfie, randtext)
+}