fix(agent/agentcontainers): read WorkspaceFolder from config (#18467)

DanielleMaywood · web-flow · commit d61353f4687f · 2025-06-20T16:34:30.000+01:00
Instead of exec'ing `pwd` inside of the container, we instead read
`WorkspaceFolder` from the outcome of `read-configuration`.
diff --git a/agent/agentcontainers/api.go b/agent/agentcontainers/api.go
@@ -1,11 +1,9 @@
 package agentcontainers
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"os"
 	"path"
@@ -1114,27 +1112,6 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 	if proc.agent.ID == uuid.Nil || maybeRecreateSubAgent {
 		subAgentConfig.Architecture = arch
 
-		// Detect workspace folder by executing `pwd` in the container.
-		// NOTE(mafredri): This is a quick and dirty way to detect the
-		// workspace folder inside the container. In the future we will
-		// rely more on `devcontainer read-configuration`.
-		var pwdBuf bytes.Buffer
-		err = api.dccli.Exec(ctx, dc.WorkspaceFolder, dc.ConfigPath, "pwd", []string{},
-			WithExecOutput(&pwdBuf, io.Discard),
-			WithExecContainerID(container.ID),
-		)
-		if err != nil {
-			return xerrors.Errorf("check workspace folder in container: %w", err)
-		}
-		directory := strings.TrimSpace(pwdBuf.String())
-		if directory == "" {
-			logger.Warn(ctx, "detected workspace folder is empty, using default workspace folder",
-				slog.F("default_workspace_folder", DevcontainerDefaultContainerWorkspaceFolder),
-			)
-			directory = DevcontainerDefaultContainerWorkspaceFolder
-		}
-		subAgentConfig.Directory = directory
-
 		displayAppsMap := map[codersdk.DisplayApp]bool{
 			// NOTE(DanielleMaywood):
 			// We use the same defaults here as set in terraform-provider-coder.
@@ -1146,7 +1123,10 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 			codersdk.DisplayAppPortForward:    true,
 		}
 
-		var appsWithPossibleDuplicates []SubAgentApp
+		var (
+			appsWithPossibleDuplicates []SubAgentApp
+			workspaceFolder            = DevcontainerDefaultContainerWorkspaceFolder
+		)
 
 		if err := func() error {
 			var (
@@ -1167,6 +1147,8 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 				return err
 			}
 
+			workspaceFolder = config.Workspace.WorkspaceFolder
+
 			// NOTE(DanielleMaywood):
 			// We only want to take an agent name specified in the root customization layer.
 			// This restricts the ability for a feature to specify the agent name. We may revisit
@@ -1241,6 +1223,7 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 
 		subAgentConfig.DisplayApps = displayApps
 		subAgentConfig.Apps = apps
+		subAgentConfig.Directory = workspaceFolder
 	}
 
 	deleteSubAgent := proc.agent.ID != uuid.Nil && maybeRecreateSubAgent && !proc.agent.EqualConfig(subAgentConfig)
diff --git a/agent/agentcontainers/api_test.go b/agent/agentcontainers/api_test.go
@@ -1262,6 +1262,11 @@ func TestAPI(t *testing.T) {
 				deleteErrC: make(chan error, 1),
 			}
 			fakeDCCLI = &fakeDevcontainerCLI{
+				readConfig: agentcontainers.DevcontainerConfig{
+					Workspace: agentcontainers.DevcontainerWorkspace{
+						WorkspaceFolder: "/workspaces/coder",
+					},
+				},
 				execErrC:       make(chan func(cmd string, args ...string) error, 1),
 				readConfigErrC: make(chan func(envs []string) error, 1),
 			}
@@ -1273,8 +1278,8 @@ func TestAPI(t *testing.T) {
 				Running:      true,
 				CreatedAt:    time.Now(),
 				Labels: map[string]string{
-					agentcontainers.DevcontainerLocalFolderLabel: "/workspaces",
-					agentcontainers.DevcontainerConfigFileLabel:  "/workspace/.devcontainer/devcontainer.json",
+					agentcontainers.DevcontainerLocalFolderLabel: "/home/coder/coder",
+					agentcontainers.DevcontainerConfigFileLabel:  "/home/coder/coder/.devcontainer/devcontainer.json",
 				},
 			}
 		)
@@ -1320,11 +1325,6 @@ func TestAPI(t *testing.T) {
 
 		// Allow initial agent creation and injection to succeed.
 		testutil.RequireSend(ctx, t, fakeSAC.createErrC, nil)
-		testutil.RequireSend(ctx, t, fakeDCCLI.execErrC, func(cmd string, args ...string) error {
-			assert.Equal(t, "pwd", cmd)
-			assert.Empty(t, args)
-			return nil
-		}) // Exec pwd.
 		testutil.RequireSend(ctx, t, fakeDCCLI.readConfigErrC, func(envs []string) error {
 			assert.Contains(t, envs, "CODER_WORKSPACE_AGENT_NAME=test-container")
 			assert.Contains(t, envs, "CODER_WORKSPACE_NAME=test-workspace")
@@ -1350,7 +1350,7 @@ func TestAPI(t *testing.T) {
 		// Verify agent was created.
 		require.Len(t, fakeSAC.created, 1)
 		assert.Equal(t, "test-container", fakeSAC.created[0].Name)
-		assert.Equal(t, "/workspaces", fakeSAC.created[0].Directory)
+		assert.Equal(t, "/workspaces/coder", fakeSAC.created[0].Directory)
 		assert.Len(t, fakeSAC.deleted, 0)
 
 		t.Log("Agent injected successfully, now testing reinjection into the same container...")
@@ -1467,11 +1467,6 @@ func TestAPI(t *testing.T) {
 		testutil.RequireSend(ctx, t, fakeSAC.deleteErrC, nil)
 		// Expect the agent to be recreated.
 		testutil.RequireSend(ctx, t, fakeSAC.createErrC, nil)
-		testutil.RequireSend(ctx, t, fakeDCCLI.execErrC, func(cmd string, args ...string) error {
-			assert.Equal(t, "pwd", cmd)
-			assert.Empty(t, args)
-			return nil
-		}) // Exec pwd.
 		testutil.RequireSend(ctx, t, fakeDCCLI.readConfigErrC, func(envs []string) error {
 			assert.Contains(t, envs, "CODER_WORKSPACE_AGENT_NAME=test-container")
 			assert.Contains(t, envs, "CODER_WORKSPACE_NAME=test-workspace")
@@ -1814,7 +1809,6 @@ func TestAPI(t *testing.T) {
 								},
 							},
 						},
-						execErrC: make(chan func(cmd string, args ...string) error, 1),
 					}
 
 					testContainer = codersdk.WorkspaceAgentContainer{
@@ -1861,15 +1855,9 @@ func TestAPI(t *testing.T) {
 
 				// Close before api.Close() defer to avoid deadlock after test.
 				defer close(fSAC.createErrC)
-				defer close(fDCCLI.execErrC)
 
 				// Given: We allow agent creation and injection to succeed.
 				testutil.RequireSend(ctx, t, fSAC.createErrC, nil)
-				testutil.RequireSend(ctx, t, fDCCLI.execErrC, func(cmd string, args ...string) error {
-					assert.Equal(t, "pwd", cmd)
-					assert.Empty(t, args)
-					return nil
-				})
 
 				// Wait until the ticker has been registered.
 				tickerTrap.MustWait(ctx).MustRelease(ctx)
@@ -1913,7 +1901,6 @@ func TestAPI(t *testing.T) {
 					},
 				},
 				readConfigErrC: make(chan func(envs []string) error, 2),
-				execErrC:       make(chan func(cmd string, args ...string) error, 1),
 			}
 
 			testContainer = codersdk.WorkspaceAgentContainer{
@@ -1960,16 +1947,10 @@ func TestAPI(t *testing.T) {
 
 		// Close before api.Close() defer to avoid deadlock after test.
 		defer close(fSAC.createErrC)
-		defer close(fDCCLI.execErrC)
 		defer close(fDCCLI.readConfigErrC)
 
 		// Given: We allow agent creation and injection to succeed.
 		testutil.RequireSend(ctx, t, fSAC.createErrC, nil)
-		testutil.RequireSend(ctx, t, fDCCLI.execErrC, func(cmd string, args ...string) error {
-			assert.Equal(t, "pwd", cmd)
-			assert.Empty(t, args)
-			return nil
-		})
 		testutil.RequireSend(ctx, t, fDCCLI.readConfigErrC, func(env []string) error {
 			// We expect the wrong workspace agent name passed in first.
 			assert.Contains(t, env, "CODER_WORKSPACE_AGENT_NAME=test-container")
diff --git a/agent/agentcontainers/devcontainercli.go b/agent/agentcontainers/devcontainercli.go
@@ -22,6 +22,7 @@ import (
 type DevcontainerConfig struct {
 	MergedConfiguration DevcontainerMergedConfiguration `json:"mergedConfiguration"`
 	Configuration       DevcontainerConfiguration       `json:"configuration"`
+	Workspace           DevcontainerWorkspace           `json:"workspace"`
 }
 
 type DevcontainerMergedConfiguration struct {
@@ -46,6 +47,10 @@ type CoderCustomization struct {
 	Name        string                       `json:"name,omitempty"`
 }
 
+type DevcontainerWorkspace struct {
+	WorkspaceFolder string `json:"workspaceFolder"`
+}
+
 // DevcontainerCLI is an interface for the devcontainer CLI.
 type DevcontainerCLI interface {
 	Up(ctx context.Context, workspaceFolder, configPath string, opts ...DevcontainerCLIUpOptions) (id string, err error)
