Implement lazy-loading at top level

src/aiidalab_qe/app/configuration/__init__.py

@@ -9,12 +9,8 @@
 import traitlets as tl
 
 from aiida import orm
-from aiidalab_qe.app.utils import get_entry_items
 from aiidalab_widgets_base import WizardAppWidgetStep
 
-from .advanced import AdvancedSettings
-from .workflow import WorkChainSettings
-
 
 class ConfigureQeAppWorkChainStep(ipw.VBox, WizardAppWidgetStep):
     confirmed = tl.Bool()
@@ -24,7 +20,12 @@ class ConfigureQeAppWorkChainStep(ipw.VBox, WizardAppWidgetStep):
     # output dictionary
     configuration_parameters = tl.Dict()
 
-    def __init__(self, **kwargs):
+    def render(self):
+        from aiidalab_qe.app.utils import get_entry_items
+
+        from .advanced import AdvancedSettings
+        from .workflow import WorkChainSettings
+
         self.workchain_settings = WorkChainSettings()
         self.advanced_settings = AdvancedSettings()
 
@@ -100,22 +101,20 @@ def __init__(self, **kwargs):
 
         self.confirm_button.on_click(self.confirm)
 
-        super().__init__(
-            children=[
-                self.tab,
-                self._submission_blocker_messages,
-                self.confirm_button,
-            ],
-            **kwargs,
-        )
+        self.children = [
+            self.tab,
+            self._submission_blocker_messages,
+            self.confirm_button,
+        ]
 
     @tl.observe("previous_step_state")
     def _observe_previous_step_state(self, _change):
         self._update_state()
 
     def get_configuration_parameters(self):
         """Get the parameters of the configuration step."""
-
+        if not hasattr(self, "tab"):
+            return {}
         return {s.identifier: s.get_panel_value() for s in self.tab.children}
 
     def set_configuration_parameters(self, parameters):

src/aiidalab_qe/app/main.py

@@ -5,19 +5,18 @@
 
 import ipywidgets as ipw
 
-from aiida.orm import load_node
-from aiidalab_qe.app.configuration import ConfigureQeAppWorkChainStep
-from aiidalab_qe.app.result import ViewQeAppWorkChainStatusAndResultsStep
-from aiidalab_qe.app.structure import StructureSelectionStep
-from aiidalab_qe.app.submission import SubmitQeAppWorkChainStep
-from aiidalab_qe.common import QeAppWorkChainSelector
-from aiidalab_widgets_base import WizardAppWidget, WizardAppWidgetStep
-
 
 class App(ipw.VBox):
     """The main widget that combines all the application steps together."""
 
     def __init__(self, qe_auto_setup=True):
+        from aiidalab_qe.app.configuration import ConfigureQeAppWorkChainStep
+        from aiidalab_qe.app.result import ViewQeAppWorkChainStatusAndResultsStep
+        from aiidalab_qe.app.structure import StructureSelectionStep
+        from aiidalab_qe.app.submission import SubmitQeAppWorkChainStep
+        from aiidalab_qe.common import QeAppWorkChainSelector
+        from aiidalab_widgets_base import WizardAppWidget
+
         # Create the application steps
         self.structure_step = StructureSelectionStep(auto_advance=True)
         self.structure_step.observe(self._observe_structure_selection, "structure")
@@ -85,6 +84,8 @@ def __init__(self, qe_auto_setup=True):
             ]
         )
 
+        self._wizard_app_widget.selected_index = None
+
     @property
     def steps(self):
         return self._wizard_app_widget.steps
@@ -100,6 +101,8 @@ def _observe_structure_selection(self, change):
 
     def _observe_selected_index(self, change):
         """Check unsaved change in the step when leaving the step."""
+        from aiidalab_widgets_base import WizardAppWidgetStep
+
         # no accordion tab is selected
         if not change["new"]:
             return
@@ -120,6 +123,7 @@ def _observe_selected_index(self, change):
         self.submit_step.external_submission_blockers = blockers
 
     def _observe_process_selection(self, change):
+        from aiida.orm import load_node
         from aiida.orm.utils.serialize import deserialize_unsafe
 
         if change["old"] == change["new"]:

src/aiidalab_qe/app/result/__init__.py

@@ -2,14 +2,7 @@
 import traitlets as tl
 
 from aiida import orm
-from aiida.engine import ProcessState
-from aiida.engine.processes import control
-from aiidalab_widgets_base import (
-    AiidaNodeViewWidget,
-    ProcessMonitor,
-    ProcessNodesTreeWidget,
-    WizardAppWidgetStep,
-)
+from aiidalab_widgets_base import WizardAppWidgetStep
 
 # trigger registration of the viewer widget:
 from .workchain_viewer import WorkChainViewer  # noqa: F401
@@ -22,7 +15,13 @@
 class ViewQeAppWorkChainStatusAndResultsStep(ipw.VBox, WizardAppWidgetStep):
     process = tl.Unicode(allow_none=True)
 
-    def __init__(self, **kwargs):
+    def render(self):
+        from aiidalab_widgets_base import (
+            AiidaNodeViewWidget,
+            ProcessMonitor,
+            ProcessNodesTreeWidget,
+        )
+
         self.process_tree = ProcessNodesTreeWidget()
         ipw.dlink(
             (self, "process"),
@@ -57,15 +56,13 @@ def __init__(self, **kwargs):
         self.kill_button.on_click(self._on_click_kill_button)
         self.process_info = ipw.HTML()
 
-        super().__init__(
-            [
-                ipw.HBox(children=[self.kill_button, self.process_info]),
-                self.process_status,
-            ],
-            **kwargs,
-        )
+        self.children = [
+            ipw.HBox(children=[self.kill_button, self.process_info]),
+            self.process_status,
+        ]
 
         self._update_kill_button_layout()
+        self.observe(self._observe_process, "process")
 
     def can_reset(self):
         "Do not allow reset while process is running."
@@ -76,6 +73,8 @@ def reset(self):
 
     def _update_state(self):
         """Based on the process state, update the state of the step."""
+        from aiida.engine import ProcessState
+
         if self.process is None:
             self.state = self.State.INIT
         else:
@@ -124,13 +123,14 @@ def _on_click_kill_button(self, _=None):
         """callback for the kill button.
         First kill the process, then update the kill button layout.
         """
+        from aiida.engine.processes import control
+
         workchain = [orm.load_node(self.process)]
         control.kill_processes(workchain)
 
         # update the kill button layout
         self._update_kill_button_layout()
 
-    @tl.observe("process")
     def _observe_process(self, _):
         """Callback for when the process is changed."""
         # The order of the following calls matters,

src/aiidalab_qe/app/structure/__init__.py

@@ -8,20 +8,8 @@
 import ipywidgets as ipw
 import traitlets as tl
 
-import aiida
-from aiida_quantumespresso.data.hubbard_structure import HubbardStructureData
-from aiidalab_qe.app.utils import get_entry_items
-from aiidalab_qe.common import AddingTagsEditor
-from aiidalab_widgets_base import (
-    BasicCellEditor,
-    BasicStructureEditor,
-    OptimadeQueryWidget,
-    StructureBrowserWidget,
-    StructureExamplesWidget,
-    StructureManagerWidget,
-    StructureUploadWidget,
-    WizardAppWidgetStep,
-)
+from aiida import orm
+from aiidalab_widgets_base import WizardAppWidgetStep
 
 # The Examples list of (name, file) tuple curretly passed to
 # StructureExamplesWidget.
@@ -47,18 +35,45 @@ class StructureSelectionStep(ipw.VBox, WizardAppWidgetStep):
     structure importers and the structure editors can be extended by plugins.
     """
 
-    structure = tl.Instance(aiida.orm.StructureData, allow_none=True)
-    confirmed_structure = tl.Instance(aiida.orm.StructureData, allow_none=True)
+    structure = tl.Instance(orm.StructureData, allow_none=True)
+    confirmed_structure = tl.Instance(orm.StructureData, allow_none=True)
 
     def __init__(self, description=None, **kwargs):
+        if description is None:
+            description = ipw.HTML(
+                """
+                <p>Select a structure from one of the following sources and then click
+                "Confirm" to go to the next step. </p><i class="fa fa-exclamation-circle"
+                aria-hidden="true"></i> Currently only three-dimensional structures are
+                supported.
+                """
+            )
+        self.description = description
+        super().__init__(**kwargs)
+
+    def render(self):
+        """docstring"""
+        from aiida_quantumespresso.data.hubbard_structure import HubbardStructureData
+        from aiidalab_qe.app.utils import get_entry_items
+        from aiidalab_qe.common import AddingTagsEditor
+        from aiidalab_widgets_base import (
+            BasicCellEditor,
+            BasicStructureEditor,
+            OptimadeQueryWidget,
+            StructureBrowserWidget,
+            StructureExamplesWidget,
+            StructureManagerWidget,
+            StructureUploadWidget,
+        )
+
         importers = [
             StructureUploadWidget(title="Upload file"),
             OptimadeQueryWidget(embedded=False),
             StructureBrowserWidget(
                 title="AiiDA database",
                 query_types=(
-                    aiida.orm.StructureData,
-                    aiida.orm.CifData,
+                    orm.StructureData,
+                    orm.CifData,
                     HubbardStructureData,
                 ),
             ),
@@ -84,17 +99,6 @@ def __init__(self, description=None, **kwargs):
             configuration_tabs=["Cell", "Selection", "Appearance", "Download"],
         )
 
-        if description is None:
-            description = ipw.HTML(
-                """
-                <p>Select a structure from one of the following sources and then click
-                "Confirm" to go to the next step. </p><i class="fa fa-exclamation-circle"
-                aria-hidden="true"></i> Currently only three-dimensional structures are
-                supported.
-                """
-            )
-        self.description = description
-
         self.structure_name_text = ipw.Text(
             placeholder="[No structure selected]",
             description="Selected:",
@@ -117,16 +121,13 @@ def __init__(self, description=None, **kwargs):
         # structure manager to our 'structure' traitlet:
         ipw.dlink((self.manager, "structure_node"), (self, "structure"))
 
-        super().__init__(
-            children=[
-                self.description,
-                self.manager,
-                self.structure_name_text,
-                self.message_area,
-                self.confirm_button,
-            ],
-            **kwargs,
-        )
+        self.children = [
+            self.description,
+            self.manager,
+            self.structure_name_text,
+            self.message_area,
+            self.confirm_button,
+        ]
 
     @tl.default("state")
     def _default_state(self):