CLI: Allow specifying output filename in verdi node graph generate (#…

…5897)

The `verdi node graph generate` now takes an optional argument to define
the filename to which the output should be written. The call to `render`
now uses the `outfile` argument instead of `filename` since the former
respects the specified value, whereas the latter will add a suffix that
corresponds to the requested output format.

Co-authored-by: Sebastiaan Huber <mail@sphuber.net>

aiida/cmdline/commands/cmd_node.py

@@ -435,10 +435,11 @@ def verdi_graph():
     multiple=True
 )
 @click.option('-s', '--show', is_flag=True, help='Open the rendered result with the default application.')
+@arguments.OUTPUT_FILE(required=False)
 @decorators.with_dbenv()
 def graph_generate(
     root_node, link_types, identifier, ancestor_depth, descendant_depth, process_out, process_in, engine, output_format,
-    highlight_classes, show
+    highlight_classes, show, output_file
 ):
     """
     Generate a graph from a ROOT_NODE (specified by pk or uuid).
@@ -468,11 +469,13 @@ def graph_generate(
         include_process_inputs=process_in,
         highlight_classes=highlight_classes,
     )
-    output_file_name = graph.graphviz.render(
-        filename=f'{root_node.pk}.{engine}', format=output_format, view=show, cleanup=True
-    )
 
-    echo.echo_success(f'Output file: {output_file_name}')
+    if not output_file:
+        output_file = pathlib.Path(f'{root_node.pk}.{engine}.{output_format}')
+
+    output_file_name = graph.graphviz.render(outfile=output_file, format=output_format, view=show, cleanup=True)
+
+    echo.echo_success(f'Output written to `{output_file_name}`')
 
 
 @verdi_node.group('comment')

tests/cmdline/commands/test_node.py

@@ -417,6 +417,15 @@ def test_node_id_label_format(self, run_cli_command):
             finally:
                 delete_temporary_file(filename)
 
+    @pytest.mark.parametrize('output_file', ('without_extension', 'without_extension.pdf'))
+    def test_output_file(self, run_cli_command, output_file):
+        """Test that the output file can be specified through an argument."""
+        try:
+            run_cli_command(cmd_node.graph_generate, [str(self.node.pk), output_file])
+            assert os.path.isfile(output_file)
+        finally:
+            delete_temporary_file(output_file)
+
 
 COMMENT = 'Well I never...'