feat: add API/SDK support for autostop extension (#1778)

* Adds deadline column to workspace_builds, associated DB/API plumbing
* database: Upon inserting a row into workspace_builds, deadline will 
  initially be zero.
* autobuild: Executor now checks the Deadline field of the workspace_build
  for the purpose of autostop logic.
* coderd: Adds a new route /api/v2/workspaces/:workspace/extend which allows
  updating the deadline of the currently active workspace build. The new
  deadline must be after the existing deadline, and not the zero time.
* provisionerd: updates workspace_build.deadline upon successful workspace 
  build completion (equal to now plus workspace TTL, if it exists).

coderd/workspaces.go

@@ -477,7 +477,8 @@ func (api *API) postWorkspacesByOrganization(rw http.ResponseWriter, r *http.Req
 			InitiatorID:       apiKey.UserID,
 			Transition:        database.WorkspaceTransitionStart,
 			JobID:             provisionerJob.ID,
-			BuildNumber:       1, // First build!
+			BuildNumber:       1,           // First build!
+			Deadline:          time.Time{}, // provisionerd will set this upon success
 		})
 		if err != nil {
 			return xerrors.Errorf("insert workspace build: %w", err)
@@ -570,6 +571,69 @@ func (api *API) putWorkspaceTTL(rw http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (api *API) putExtendWorkspace(rw http.ResponseWriter, r *http.Request) {
+	workspace := httpmw.WorkspaceParam(r)
+
+	if !api.Authorize(rw, r, rbac.ActionUpdate, workspace) {
+		return
+	}
+
+	var req codersdk.PutExtendWorkspaceRequest
+	if !httpapi.Read(rw, r, &req) {
+		return
+	}
+
+	var code = http.StatusOK
+
+	err := api.Database.InTx(func(s database.Store) error {
+		build, err := s.GetLatestWorkspaceBuildByWorkspaceID(r.Context(), workspace.ID)
+		if err != nil {
+			code = http.StatusInternalServerError
+			return xerrors.Errorf("get latest workspace build: %w", err)
+		}
+
+		if build.Transition != database.WorkspaceTransitionStart {
+			code = http.StatusConflict
+			return xerrors.Errorf("workspace must be started, current status: %s", build.Transition)
+		}
+
+		newDeadline := req.Deadline.Truncate(time.Minute).UTC()
+		if newDeadline.IsZero() {
+			// This should not be possible because the struct validation field enforces a non-zero value.
+			code = http.StatusBadRequest
+			return xerrors.New("new deadline cannot be zero")
+		}
+
+		if newDeadline.Before(build.Deadline) || newDeadline.Before(time.Now()) {
+			code = http.StatusBadRequest
+			return xerrors.Errorf("new deadline %q must be after existing deadline %q", newDeadline.Format(time.RFC3339), build.Deadline.Format(time.RFC3339))
+		}
+
+		// both newDeadline and build.Deadline are truncated to time.Minute
+		if newDeadline == build.Deadline {
+			code = http.StatusNotModified
+			return nil
+		}
+
+		if err := s.UpdateWorkspaceBuildByID(r.Context(), database.UpdateWorkspaceBuildByIDParams{
+			ID:               build.ID,
+			UpdatedAt:        build.UpdatedAt,
+			ProvisionerState: build.ProvisionerState,
+			Deadline:         newDeadline,
+		}); err != nil {
+			return xerrors.Errorf("update workspace build: %w", err)
+		}
+
+		return nil
+	})
+
+	var resp = httpapi.Response{}
+	if err != nil {
+		resp.Message = err.Error()
+	}
+	httpapi.Write(rw, code, resp)
+}
+
 func (api *API) watchWorkspace(rw http.ResponseWriter, r *http.Request) {
 	workspace := httpmw.WorkspaceParam(r)