feat: Initial support for Compose configs (#116)

test/e2e/helpers.go

@@ -0,0 +1,105 @@
+package e2e
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/docker/docker/api/types/container"
+	dockerclient "github.com/docker/docker/client"
+	"github.com/docker/docker/pkg/stdcopy"
+	"github.com/psviderski/uncloud/internal/ucind"
+	"github.com/stretchr/testify/assert"
+)
+
+type fileInfo struct {
+	permissions os.FileMode
+	content     string
+}
+
+// a helper function that takes a machine, container name inside it and file path, and returns the file contents along with metadata
+//
+// Uncloud API does not currently expose exec functionality to run commands inside containers.
+// Instead this helper function uses "docker cp" inside the ucind container to copy the file from the target container
+// to a temporary location (also inside the ucind container), and then inspect its content and permissions.
+func readFileInfoInContainer(t *testing.T, machine *ucind.Machine, containerName, filePath string) (fileInfo, error) {
+	t.Helper()
+	ctx := context.Background()
+
+	dockerCli, err := dockerclient.NewClientWithOpts(dockerclient.FromEnv)
+	if err != nil {
+		return fileInfo{}, err
+	}
+	defer dockerCli.Close()
+
+	machineContainerName := fmt.Sprintf("%s-%s", machine.ClusterName, machine.Name)
+
+	//  1. Create an exec instance
+	fileLocation := fmt.Sprintf("%s:%s", containerName, filePath)
+	tmpFileLocation := fmt.Sprintf("/tmp/%s-%s", containerName, filepath.Base(filePath))
+
+	cmdDocker := fmt.Sprintf("docker cp %s %s", fileLocation, tmpFileLocation)
+	cmdPermissions := fmt.Sprintf("stat -c %%a %s", tmpFileLocation)
+	cmdCat := fmt.Sprintf("cat %s", tmpFileLocation)
+	cmdCombined := fmt.Sprintf("%s; %s; %s", cmdDocker, cmdPermissions, cmdCat)
+
+	execConfig := container.ExecOptions{
+		Cmd:          []string{"sh", "-ec", cmdCombined},
+		AttachStdout: true,
+		AttachStderr: true,
+	}
+	resp, err := dockerCli.ContainerExecCreate(ctx, machineContainerName, execConfig)
+	if err != nil {
+		return fileInfo{}, err
+	}
+
+	// 2. Attach to the exec session
+	hijackResp, err := dockerCli.ContainerExecAttach(ctx, resp.ID, container.ExecAttachOptions{})
+	if err != nil {
+		return fileInfo{}, err
+	}
+	defer hijackResp.Close()
+
+	// 3. Inspect result
+	inspectResp, err := dockerCli.ContainerExecInspect(ctx, resp.ID)
+	if err != nil {
+		return fileInfo{}, err
+	}
+
+	assert.Equal(t, 0, inspectResp.ExitCode, "Expected exit code 0 from exec command")
+
+	// 4. Read output to string using stdcopy to demultiplex the Docker stream
+	var stdout, stderr strings.Builder
+	_, err = stdcopy.StdCopy(&stdout, &stderr, hijackResp.Reader)
+	if err != nil {
+		return fileInfo{}, err
+	}
+
+	if stderr.Len() > 0 {
+		return fileInfo{}, fmt.Errorf("stderr output: %s", stderr.String())
+	}
+
+	// 5. Parse output: permissions, content
+	outputLines := strings.SplitN(stdout.String(), "\n", 2)
+	if len(outputLines) < 2 {
+		return fileInfo{}, fmt.Errorf("unexpected output format, expected at least 2 lines, got %d", len(outputLines))
+	}
+	permissions := outputLines[0]
+	// convert to octal number
+	permissionsOctal, err := strconv.ParseInt(permissions, 8, 32)
+	if err != nil {
+		return fileInfo{}, fmt.Errorf("parse file permissions: %w", err)
+	}
+	mode := os.FileMode(permissionsOctal)
+
+	fileContent := outputLines[1]
+
+	return fileInfo{
+		permissions: mode,
+		content:     fileContent,
+	}, nil
+}