Add --also-remote option to verdi process dump

Tries to open a connection to the remote Computer using the transport of
the CalcJobNode, and `get`s the files and folders which were not
originally dumped, either as they weren't part of the CalcJobNode's
repository or retrieved.

src/aiida/cmdline/commands/cmd_process.py

@@ -576,6 +576,13 @@ def process_repair(manager, broker, dry_run):
     show_default=True,
     help='Include extras in the `.aiida_node_metadata.yaml` written for every `ProcessNode`.',
 )
+@click.option(
+    '--also-remote',
+    is_flag=True,
+    default=False,
+    show_default=True,
+    help='If true, try to obtain also intermediate files on the remote computer that were not initially retrieved.',
+)
 @click.option(
     '-f',
     '--flat',
@@ -591,19 +598,21 @@ def process_dump(
     include_outputs,
     include_attributes,
     include_extras,
+    also_remote,
     flat,
 ) -> None:
     """Dump process input and output files to disk.
 
     Child calculations/workflows (also called `CalcJob`s/`CalcFunction`s and `WorkChain`s/`WorkFunction`s in AiiDA
     jargon) run by the parent workflow are contained in the directory tree as sub-folders and are sorted by their
-    creation time.  The directory tree thus mirrors the logical execution of the workflow, which can also be queried by
+    creation time. The directory tree thus mirrors the logical execution of the workflow, which can also be queried by
     running `verdi process status <pk>` on the command line.
 
     By default, input and output files of each calculation can be found in the corresponding "inputs" and
     "outputs" directories (the former also contains the hidden ".aiida" folder with machine-readable job execution
     settings). Additional input and output files (depending on the type of calculation) are placed in the "node_inputs"
-    and "node_outputs", respectively.
+    and "node_outputs", respectively. Using the `--also-remote` flag, additional files of the `remote_workdir` on the
+    Computer where the CalcJobs were run can be retrieved (if they still exist on the remote).
 
     Lastly, every folder also contains a hidden, human-readable `.aiida_node_metadata.yaml` file with the relevant AiiDA
     node data for further inspection.
@@ -618,8 +627,17 @@ def process_dump(
         include_extras=include_extras,
         overwrite=overwrite,
         flat=flat,
+        also_remote=also_remote,
     )
 
+    if also_remote:
+        echo.echo_report(
+            '`--also-remote` set to True. Will try to retrieve additional files from the `workdir` of the remote Computer.'  # noqa: E501
+        )
+        echo.echo_report(
+            'If files are non-existent, they will be skipped silently. Check if the output files are what you expect.'
+        )
+
     try:
         dump_path = process_dumper.dump(process_node=process, output_path=path)
     except FileExistsError:

src/aiida/tools/dumping/processes.py

@@ -10,6 +10,7 @@
 
 from __future__ import annotations
 
+import itertools as it
 import logging
 from pathlib import Path
 from types import SimpleNamespace
@@ -18,7 +19,7 @@
 import yaml
 
 from aiida.common import LinkType
-from aiida.common.exceptions import NotExistentAttributeError
+from aiida.common.exceptions import ConfigurationError, NotExistentAttributeError
 from aiida.orm import (
     CalcFunctionNode,
     CalcJobNode,
@@ -30,6 +31,7 @@
     WorkFunctionNode,
 )
 from aiida.orm.utils import LinkTriple
+from aiida.orm.utils.remote import get_calcjob_remote_paths
 
 LOGGER = logging.getLogger(__name__)
 
@@ -42,13 +44,15 @@ def __init__(
         include_attributes: bool = True,
         include_extras: bool = True,
         overwrite: bool = False,
+        also_remote: bool = False,
         flat: bool = False,
     ) -> None:
         self.include_inputs = include_inputs
         self.include_outputs = include_outputs
         self.include_attributes = include_attributes
         self.include_extras = include_extras
         self.overwrite = overwrite
+        self.also_remote = also_remote
         self.flat = flat
 
     @staticmethod
@@ -285,6 +289,53 @@ def _dump_calculation(
                 link_triples=output_links,
             )
 
+        # Additional remote file retrieval should only apply for CalcJobNodes, not CalcFunctionNodes
+        if self.also_remote and isinstance(calculation_node, CalcJobNode):
+            self._dump_calculation_remote_files(calcjob_node=calculation_node, output_path=output_path)
+
+    def _dump_calculation_remote_files(self, calcjob_node: CalcJobNode, output_path: Path) -> None:
+        """Dump the additional remote files attached to a `CalcJobNode` to a specified output path.
+
+        :param calcjob_node: The `CalcJobNode` to be dumped.
+        :param output_path: The path where the files will be dumped.
+        """
+
+        remote_workdir = calcjob_node.get_remote_workdir()
+        if remote_workdir is None:
+            raise NotExistentAttributeError(f"CalcJobNode <{calcjob_node.pk}> doesn't have a `remote_workdir`.")
+
+        # Exclude the objects that were already dumped, as they were either originally retrieved via `retrieve_list`
+        # or are already part of the file repository of the CalcJobNode, e.g. the `aiida.in` and `_aiidasubmit.sh`
+        retrieve_list = list(calcjob_node.get_retrieve_list())  # type: ignore[arg-type]
+        repository_list = calcjob_node.base.repository.list_object_names()
+        exclude_list = retrieve_list + repository_list
+
+        # Obtain a flattened list of the `RemoteData` objects.
+        # The computer UUIDs that are the keys of the returned dictionary of `get_calcjob_remote_paths` aren't
+        # needed, as we only run the function for a single CalcJobNode using its associated transport to get the files
+        calcjob_remote_paths = get_calcjob_remote_paths(pks=[calcjob_node.pk])  # type: ignore[list-item]
+        calcjob_remote_datas = list(it.chain.from_iterable(calcjob_remote_paths.values()))  # type: ignore[union-attr]
+
+        # Unlike for the `retrieve_files_from_list` in `execmanager.py`, we only dump the files to disk, rather than
+        # also storing them in the repository via `FolderData`
+        try:
+            with calcjob_node.get_transport() as transport:
+                for calcjob_remote_data in calcjob_remote_datas:
+                    # Obtain all objects from each of the RemoteDatas associated with the CalcJobNode
+                    # (could this even be more than one?)
+                    retrieve_objects = [_ for _ in calcjob_remote_data.listdir() if _ not in exclude_list]
+                    remote_paths = [(Path(remote_workdir) / _).resolve() for _ in retrieve_objects]
+                    local_paths = [(output_path / 'remote_files' / _).resolve() for _ in retrieve_objects]
+
+                    # Transport.get() works for files and folders, so we don't need to make a distinction
+                    for rem, loc in zip(remote_paths, local_paths):
+                        transport.get(str(rem), str(loc), ignore_nonexisting=True)
+
+        # Getting the transport fails, propagate exception outwards
+        # (could just remove the except, but being explicit might make it clearer here)
+        except ConfigurationError:
+            raise
+
     def _dump_calculation_io(self, parent_path: Path, link_triples: LinkManager | List[LinkTriple]):
         """Small helper function to dump linked input/output nodes of a `CalculationNode`.