feat: add agent endpoint for querying file system

ethanndickson · ethanndickson · commit 9b1dfcb979e5 · 2025-02-28T03:14:27.000Z
diff --git a/agent/api.go b/agent/api.go
@@ -41,6 +41,7 @@ func (a *agent) apiHandler() http.Handler {
 	r.Get("/api/v0/containers", ch.ServeHTTP)
 	r.Get("/api/v0/listening-ports", lp.handler)
 	r.Get("/api/v0/netcheck", a.HandleNetcheck)
+	r.Post("/api/v0/ls", a.HandleLS)
 	r.Get("/debug/logs", a.HandleHTTPDebugLogs)
 	r.Get("/debug/magicsock", a.HandleHTTPDebugMagicsock)
 	r.Get("/debug/magicsock/debug-logging/{state}", a.HandleHTTPMagicsockDebugLoggingState)
diff --git a/agent/ls.go b/agent/ls.go
@@ -0,0 +1,136 @@
+package agent
+
+import (
+	"errors"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"golang.org/x/xerrors"
+
+	"github.com/coder/coder/v2/coderd/httpapi"
+	"github.com/coder/coder/v2/codersdk"
+)
+
+func (*agent) HandleLS(rw http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	var query LSQuery
+	if !httpapi.Read(ctx, rw, r, &query) {
+		return
+	}
+
+	resp, err := listFiles(query)
+	if err != nil {
+		switch {
+		case errors.Is(err, os.ErrNotExist):
+			httpapi.Write(ctx, rw, http.StatusNotFound, codersdk.Response{
+				Message: "Directory does not exist",
+			})
+		case errors.Is(err, os.ErrPermission):
+			httpapi.Write(ctx, rw, http.StatusForbidden, codersdk.Response{
+				Message: "Permission denied",
+			})
+		default:
+			httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+				Message: err.Error(),
+			})
+		}
+		return
+	}
+
+	httpapi.Write(ctx, rw, http.StatusOK, resp)
+}
+
+func listFiles(query LSQuery) (LSResponse, error) {
+	var base string
+	switch query.Relativity {
+	case LSRelativityHome:
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return LSResponse{}, xerrors.Errorf("failed to get user home directory: %w", err)
+		}
+		base = home
+	case LSRelativityRoot:
+		if runtime.GOOS == "windows" {
+			// TODO: Eventually, we could have a empty path with a root base
+			// return all drives.
+			// C drive should be good enough for now.
+			base = "C:\\"
+		} else {
+			base = "/"
+		}
+	default:
+		return LSResponse{}, xerrors.Errorf("unsupported relativity type %q", query.Relativity)
+	}
+
+	fullPath := append([]string{base}, query.Path...)
+	absolutePathString, err := filepath.Abs(filepath.Join(fullPath...))
+	if err != nil {
+		return LSResponse{}, xerrors.Errorf("failed to get absolute path: %w", err)
+	}
+
+	f, err := os.Open(absolutePathString)
+	if err != nil {
+		return LSResponse{}, xerrors.Errorf("failed to open directory: %w", err)
+	}
+	defer f.Close()
+
+	stat, err := f.Stat()
+	if err != nil {
+		return LSResponse{}, xerrors.Errorf("failed to stat directory: %w", err)
+	}
+
+	if !stat.IsDir() {
+		return LSResponse{}, xerrors.New("path is not a directory")
+	}
+
+	// `contents` may be partially populated even if the operation fails midway.
+	contents, _ := f.Readdir(-1)
+	respContents := make([]LSFile, 0, len(contents))
+	for _, file := range contents {
+		respContents = append(respContents, LSFile{
+			Name:               file.Name(),
+			AbsolutePathString: filepath.Join(absolutePathString, file.Name()),
+			IsDir:              file.IsDir(),
+		})
+	}
+
+	return LSResponse{
+		AbsolutePathString: absolutePathString,
+		Contents:           respContents,
+	}, nil
+}
+
+type LSQuery struct {
+	// e.g. [], ["repos", "coder"],
+	Path []string `json:"path"`
+	// Whether the supplied path is relative to the user's home directory,
+	// or the root directory.
+	Relativity LSRelativity `json:"relativity"`
+}
+
+type LSResponse struct {
+	// Returned so clients can display the full path to the user, and
+	// copy it to configure file sync
+	// e.g. Windows: "C:\\Users\\coder"
+	//      Linux: "/home/coder"
+	AbsolutePathString string   `json:"absolute_path_string"`
+	Contents           []LSFile `json:"contents"`
+}
+
+type LSFile struct {
+	Name string `json:"name"`
+	// e.g. "C:\\Users\\coder\\hello.txt"
+	//      "/home/coder/hello.txt"
+	AbsolutePathString string `json:"absolute_path_string"`
+	IsDir              bool   `json:"is_dir"`
+}
+
+type LSRelativity string
+
+const (
+	LSRelativityRoot LSRelativity = "root"
+	LSRelativityHome LSRelativity = "home"
+)
diff --git a/agent/ls_internal_test.go b/agent/ls_internal_test.go
@@ -0,0 +1,171 @@
+package agent
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestListFilesNonExistentDirectory(t *testing.T) {
+	t.Parallel()
+
+	query := LSQuery{
+		Path:       []string{"idontexist"},
+		Relativity: LSRelativityHome,
+	}
+	_, err := listFiles(query)
+	require.ErrorIs(t, err, os.ErrNotExist)
+}
+
+func TestListFilesPermissionDenied(t *testing.T) {
+	t.Parallel()
+
+	if runtime.GOOS == "windows" {
+		t.Skip("creating an unreadable-by-user directory is non-trivial on Windows")
+	}
+
+	home, err := os.UserHomeDir()
+	require.NoError(t, err)
+
+	tmpDir := t.TempDir()
+
+	reposDir := filepath.Join(tmpDir, "repos")
+	err = os.Mkdir(reposDir, 0o000)
+	require.NoError(t, err)
+
+	rel, err := filepath.Rel(home, reposDir)
+	require.NoError(t, err)
+
+	query := LSQuery{
+		Path:       pathToArray(rel),
+		Relativity: LSRelativityHome,
+	}
+	_, err = listFiles(query)
+	require.ErrorIs(t, err, os.ErrPermission)
+}
+
+func TestListFilesNotADirectory(t *testing.T) {
+	t.Parallel()
+
+	home, err := os.UserHomeDir()
+	require.NoError(t, err)
+
+	tmpDir := t.TempDir()
+
+	filePath := filepath.Join(tmpDir, "file.txt")
+	err = os.WriteFile(filePath, []byte("content"), 0o600)
+	require.NoError(t, err)
+
+	rel, err := filepath.Rel(home, filePath)
+	require.NoError(t, err)
+
+	query := LSQuery{
+		Path:       pathToArray(rel),
+		Relativity: LSRelativityHome,
+	}
+	_, err = listFiles(query)
+	require.ErrorContains(t, err, "path is not a directory")
+}
+
+func TestListFilesSuccess(t *testing.T) {
+	t.Parallel()
+
+	tc := []struct {
+		name       string
+		baseFunc   func(t *testing.T) string
+		relativity LSRelativity
+	}{
+		{
+			name: "home",
+			baseFunc: func(t *testing.T) string {
+				home, err := os.UserHomeDir()
+				require.NoError(t, err)
+				return home
+			},
+			relativity: LSRelativityHome,
+		},
+		{
+			name: "root",
+			baseFunc: func(t *testing.T) string {
+				if runtime.GOOS == "windows" {
+					return "C:\\"
+				}
+				return "/"
+			},
+			relativity: LSRelativityRoot,
+		},
+	}
+
+	for _, tc := range tc {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			base := tc.baseFunc(t)
+			tmpDir := t.TempDir()
+
+			reposDir := filepath.Join(tmpDir, "repos")
+			err := os.Mkdir(reposDir, 0o755)
+			require.NoError(t, err)
+
+			downloadsDir := filepath.Join(tmpDir, "Downloads")
+			err = os.Mkdir(downloadsDir, 0o755)
+			require.NoError(t, err)
+
+			rel, err := filepath.Rel(base, tmpDir)
+			require.NoError(t, err)
+			relComponents := pathToArray(rel)
+
+			query := LSQuery{
+				Path:       relComponents,
+				Relativity: tc.relativity,
+			}
+			resp, err := listFiles(query)
+			require.NoError(t, err)
+
+			require.Equal(t, tmpDir, resp.AbsolutePathString)
+
+			var foundRepos, foundDownloads bool
+			for _, file := range resp.Contents {
+				switch file.Name {
+				case "repos":
+					foundRepos = true
+					expectedPath := filepath.Join(tmpDir, "repos")
+					require.Equal(t, expectedPath, file.AbsolutePathString)
+					require.True(t, file.IsDir)
+				case "Downloads":
+					foundDownloads = true
+					expectedPath := filepath.Join(tmpDir, "Downloads")
+					require.Equal(t, expectedPath, file.AbsolutePathString)
+					require.True(t, file.IsDir)
+				}
+			}
+			require.True(t, foundRepos && foundDownloads, "expected to find both repos and Downloads directories, got: %+v", resp.Contents)
+		})
+	}
+}
+
+func TestListFilesWindowsRoot(t *testing.T) {
+	t.Parallel()
+
+	if runtime.GOOS != "windows" {
+		t.Skip("skipping test on non-Windows OS")
+	}
+
+	query := LSQuery{
+		Path:       []string{},
+		Relativity: LSRelativityRoot,
+	}
+	resp, err := listFiles(query)
+	require.NoError(t, err)
+	require.Equal(t, "C:\\", resp.AbsolutePathString)
+}
+
+func pathToArray(path string) []string {
+	return strings.FieldsFunc(path, func(r rune) bool {
+		return r == os.PathSeparator
+	})
+}
