proposing new --format=<format> --out-file=<file.ext> feature (#17507)

* proposing new --format=file.ext feature

* change approach and some simplifications

* remove unused

* minor changes

* minor changes

* simplify a bit

* fix format

* minor changes

* fix

* move colorama deinit/reinit

* add out-file only if formatters

* revert

* wip

* do not deinit/reinit if not tty

* clean import

* minor changes

---------

Co-authored-by: czoido <[email protected]>

conan/api/output.py

@@ -294,10 +294,14 @@ def cli_out_write(data, fg=None, bg=None, endline="\n", indentation=0):
         sys.stdout.write(data)
     else:
         data = f"{' ' * indentation}{data}{endline}"
-        # https://github.com/conan-io/conan/issues/17245 avoid colorama crash and overhead
-        colorama.deinit()
-        sys.stdout.write(data)
-        colorama.reinit()
+        if sys.stdout.isatty():
+            # https://github.com/conan-io/conan/issues/17245 avoid colorama crash and overhead
+            # skip deinit/reinit if stdout is not a TTY to preserve redirected output to file
+            colorama.deinit()
+            sys.stdout.write(data)
+            colorama.reinit()
+        else:
+            sys.stdout.write(data)
 
 
 class TimedOutput:

conan/cli/command.py

@@ -1,5 +1,6 @@
 import argparse
 import textwrap
+from contextlib import redirect_stdout
 
 from conan.api.output import ConanOutput
 from conan.errors import ConanException
@@ -68,6 +69,9 @@ def _init_formatters(self, parser):
             help_message = "Select the output format: {}".format(", ".join(formatters))
             parser.add_argument('-f', '--format', action=OnceArgument, help=help_message)
 
+        parser.add_argument("--out-file", action=OnceArgument,
+                            help="Write the output of the command to the specified file instead of stdout.")
+
     @property
     def name(self):
         return self._name
@@ -83,19 +87,22 @@ def doc(self):
     def _format(self, parser, info, *args):
         parser_args, _ = parser.parse_known_args(*args)
 
-        default_format = "text"
-        try:
-            formatarg = parser_args.format or default_format
-        except AttributeError:
-            formatarg = default_format
+        formatarg = getattr(parser_args, "format", None) or "text"
+        out_file = getattr(parser_args, "out_file", None)
 
         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 out_file:
+            with open(out_file, 'w') as f:
+                with redirect_stdout(f):
+                    formatter(info)
+            ConanOutput().info(f"Formatted output saved to '{out_file}'")
+        else:
+            formatter(info)
 
     @staticmethod
     def _dispatch_errors(info):

test/integration/command_v2/test_output.py

@@ -1,3 +1,5 @@
+import json
+
 from conan.test.assets.genconanfile import GenConanfile
 from conan.test.utils.tools import TestClient
 from conan.test.utils.env import environment_update
@@ -260,3 +262,32 @@ def test_exception_errors(self):
         t.run("create . -vquiet", assert_error=True)
         assert "ERROR: Tagged error" not in t.out
         assert "ConanException: Untagged error" not in t.out
+
+
+def test_formatter_redirection_to_file():
+    c = TestClient(light=True)
+    c.save({"conanfile.py":  GenConanfile("pkg", "0.1")})
+
+    c.run("config home --out-file=cmd_out.txt")
+    assert "Formatted output saved to 'cmd_out.txt'" in c.out
+    cmd_out = c.load("cmd_out.txt")
+    assert f"{c.cache_folder}" in cmd_out
+    assert not f"{c.cache_folder}" in c.stdout
+
+    c.run("graph info . --format=json --out-file=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
+    assert not "nodes" in c.stdout
+
+    c.run("graph info . --format=html --out-file=graph.html")
+    assert "Formatted output saved to 'graph.html'" in c.out
+    html = c.load("graph.html")
+    assert "<head>" in html
+    assert not "<head>" in c.stdout
+
+    c.run("install . --format=json --out-file=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
+    assert not "nodes" in c.stdout