proposing new --format=<format> --out-file=<file.ext> feature

conan/api/output.py

@@ -8,6 +8,7 @@
 from colorama import Fore, Style
 
 from conan.errors import ConanException
+from conans.util.files import save
 
 LEVEL_QUIET = 80  # -q
 LEVEL_ERROR = 70  # Errors
@@ -285,10 +286,14 @@ def flush(self):
         self.stream.flush()
 
 
-def cli_out_write(data, fg=None, bg=None, endline="\n", indentation=0):
+def cli_out_write(data, fg=None, bg=None, endline="\n", indentation=0, filename=None):
     """
     Output to be used by formatters to dump information to stdout
     """
+    if filename is not None:
+        ConanOutput().info(f"Formatted output saved to '{filename}'")
+        save(filename, data)
+        return
     if (fg or bg) and _color_enabled(sys.stdout):  # need color
         data = f"{' ' * indentation}{fg or ''}{bg or ''}{data}{Style.RESET_ALL}{endline}"
         sys.stdout.write(data)

conan/cli/command.py

@@ -1,4 +1,5 @@
 import argparse
+import inspect
 import textwrap
 
 from conan.api.output import ConanOutput
@@ -89,13 +90,21 @@ def _format(self, parser, info, *args):
         except AttributeError:
             formatarg = default_format
 
+        filename = None
+        if "." in formatarg:
+            filename = formatarg
+            _, formatarg = formatarg.rsplit(".", 1)
+
         try:
             formatter = self._formatters[formatarg]
         except KeyError:
             raise ConanException("{} is not a known format. Supported formatters are: {}".format(
                 formatarg, ", ".join(self._help_formatters)))
 
-        formatter(info)
+        if filename and "filename" in inspect.signature(formatter).parameters.keys():
+            formatter(info, filename=filename)
+        else:
+            formatter(info)
 
     @staticmethod
     def _dispatch_errors(info):

conan/cli/formatters/graph/graph.py

@@ -138,11 +138,11 @@ def format_graph_dot(result):
     cli_out_write(_render_graph(graph, None, template, template_folder))
 
 
-def format_graph_json(result):
+def format_graph_json(result, filename=None):
     graph = result["graph"]
     field_filter = result.get("field_filter")
     package_filter = result.get("package_filter")
     serial = graph.serialize()
     serial = filter_graph(serial, package_filter=package_filter, field_filter=field_filter)
     json_result = json.dumps({"graph": serial}, indent=4)
-    cli_out_write(json_result)
+    cli_out_write(json_result, filename=filename)

test/integration/command/info/info_test.py

@@ -435,3 +435,12 @@ def requirements(self):
 
     c.run("graph info . -c tools.graph:vendor=build --build='lib*'")
     c.assert_listed_binary({"lib/1.0": (NO_SETTINGS_PACKAGE_ID, "Build")})
+
+
+def test_write_formatter_to_file():
+    c = TestClient(light=True)
+    c.save({"conanfile.py":  GenConanfile("pkg", "0.1")})
+    c.run("graph info .  --format=graph.json")
+    assert "Formatted output saved to 'graph.json'" in c.out
+    graph = json.loads(c.load("graph.json"))
+    assert len(graph["graph"]["nodes"]) == 1