diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 3eff137df..62f0c4c83 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -3,9 +3,9 @@ repos:
     rev: stable
     hooks:
     - id: black
-      language_version: python3.6
+      language_version: python3
 -   repo: https://gitlab.com/pycqa/flake8
     rev: master
     hooks:
     - id: flake8
-      language_version: python3.6
+      language_version: python3
diff --git a/dvc/command/run.py b/dvc/command/run.py
index b516dba49..c070f2708 100644
--- a/dvc/command/run.py
+++ b/dvc/command/run.py
@@ -17,12 +17,14 @@ class CmdRun(CmdBase):
                 self.args.deps,
                 self.args.outs,
                 self.args.outs_no_cache,
+                self.args.metrics,
+                self.args.metrics_no_cache,
                 self.args.command,
             ]
         ):  # pragma: no cover
             logger.error(
                 "too few arguments. Specify at least one: '-d', "
-                "'-o', '-O', 'command'."
+                "'-o', '-O', '-m', '-M', 'command'."
             )
             return 1
 
@@ -31,6 +33,7 @@ class CmdRun(CmdBase):
                 cmd=self._parsed_cmd(),
                 outs=self.args.outs,
                 outs_no_cache=self.args.outs_no_cache,
+                metrics=self.args.metrics,
                 metrics_no_cache=self.args.metrics_no_cache,
                 deps=self.args.deps,
                 fname=self.args.file,
@@ -88,22 +91,30 @@ def add_parser(subparsers, parent_parser):
         "--outs",
         action="append",
         default=[],
-        help="Declare output data file or data directory.",
+        help="Declare output file or directory.",
     )
     run_parser.add_argument(
         "-O",
         "--outs-no-cache",
         action="append",
         default=[],
-        help="Declare output regular file or directory "
-        "(sync to Git, not DVC cache).",
+        help="Declare output file or directory "
+        "(do not put into DVC cache).",
+    )
+    run_parser.add_argument(
+        "-m",
+        "--metrics",
+        action="append",
+        default=[],
+        help="Declare output metric file or directory.",
     )
     run_parser.add_argument(
         "-M",
         "--metrics-no-cache",
         action="append",
         default=[],
-        help="Declare output metric file or " "directory (not cached by DVC).",
+        help="Declare output metric file or directory "
+        "(do not put into DVC cache).",
     )
     run_parser.add_argument(
         "-f",
diff --git a/dvc/exceptions.py b/dvc/exceptions.py
index aecd8249b..a152355fd 100644
--- a/dvc/exceptions.py
+++ b/dvc/exceptions.py
@@ -11,7 +11,7 @@ class DvcException(Exception):
     """Base class for all dvc exceptions.
 
     Args:
-        msg (str): message for this exception.
+        msg (unicode): message for this exception.
         cause (Exception): optional cause exception.
     """
 
@@ -33,7 +33,7 @@ class OutputDuplicationError(DvcException):
     stage.
 
     Args:
-        output (str): path to the file/directory.
+        output (unicode): path to the file/directory.
         stages (list): list of paths to stages.
     """
 
diff --git a/dvc/logger.py b/dvc/logger.py
index 824436a50..fcc0663fd 100644
--- a/dvc/logger.py
+++ b/dvc/logger.py
@@ -2,6 +2,7 @@
 
 from __future__ import unicode_literals
 
+from dvc.exceptions import DvcException
 from dvc.utils.compat import str
 
 import re
@@ -63,8 +64,8 @@ def box(message, border_color=None):
     """Prints a message in a box.
 
     Args:
-        message (str): message to print.
-        border_color (str): name of a color to outline the box with.
+        message (unicode): message to print.
+        border_color (unicode): name of a color to outline the box with.
     """
     lines = message.split("\n")
     max_width = max(_visual_width(line) for line in lines)
@@ -230,7 +231,7 @@ def _walk_exc(exc):
             tb_list.insert(0, str(exc.cause_tb))
         exc = exc.cause
 
-    return (exc_list, tb_list)
+    return exc_list, tb_list
 
 
 def _parse_exc():
@@ -260,6 +261,10 @@ def _description(message, exception):
         description = "{exception}"
     elif message:
         description = "{message}"
+    else:
+        raise DvcException(
+            "Unexpected error - either exception or message must be provided"
+        )
 
     return description.format(message=message, exception=exception)
 
diff --git a/dvc/project.py b/dvc/project.py
index 363c6b275..a81309e7f 100644
--- a/dvc/project.py
+++ b/dvc/project.py
@@ -370,10 +370,11 @@ class Project(object):
     def run(
         self,
         cmd=None,
-        deps=[],
-        outs=[],
-        outs_no_cache=[],
-        metrics_no_cache=[],
+        deps=None,
+        outs=None,
+        outs_no_cache=None,
+        metrics=None,
+        metrics_no_cache=None,
         fname=None,
         cwd=os.curdir,
         no_exec=False,
@@ -383,6 +384,17 @@ class Project(object):
     ):
         from dvc.stage import Stage
 
+        if outs is None:
+            outs = []
+        if deps is None:
+            deps = []
+        if outs_no_cache is None:
+            outs_no_cache = []
+        if metrics is None:
+            metrics = []
+        if metrics_no_cache is None:
+            metrics_no_cache = []
+
         with self.state:
             stage = Stage.create(
                 project=self,
@@ -391,6 +403,7 @@ class Project(object):
                 cwd=cwd,
                 outs=outs,
                 outs_no_cache=outs_no_cache,
+                metrics=metrics,
                 metrics_no_cache=metrics_no_cache,
                 deps=deps,
                 overwrite=overwrite,
@@ -1017,14 +1030,16 @@ class Project(object):
                 )
             return self._local_status(target, with_deps=with_deps)
 
-    def _read_metric_json(self, fd, json_path):
+    @staticmethod
+    def _read_metric_json(fd, json_path):
         import json
         from jsonpath_rw import parse
 
         parser = parse(json_path)
         return [x.value for x in parser.find(json.load(fd))]
 
-    def _do_read_metric_xsv(self, reader, row, col):
+    @staticmethod
+    def _do_read_metric_xsv(reader, row, col):
         if col is not None and row is not None:
             return [reader[row][col]]
         elif col is not None:
@@ -1033,22 +1048,24 @@ class Project(object):
             return reader[row]
         return None
 
-    def _read_metric_hxsv(self, fd, hxsv_path, delimiter):
+    @classmethod
+    def _read_metric_hxsv(cls, fd, hxsv_path, delimiter):
         import csv
 
         col, row = hxsv_path.split(",")
         row = int(row)
         reader = list(csv.DictReader(fd, delimiter=builtin_str(delimiter)))
-        return self._do_read_metric_xsv(reader, row, col)
+        return cls._do_read_metric_xsv(reader, row, col)
 
-    def _read_metric_xsv(self, fd, xsv_path, delimiter):
+    @classmethod
+    def _read_metric_xsv(cls, fd, xsv_path, delimiter):
         import csv
 
         col, row = xsv_path.split(",")
         row = int(row)
         col = int(col)
         reader = list(csv.reader(fd, delimiter=builtin_str(delimiter)))
-        return self._do_read_metric_xsv(reader, row, col)
+        return cls._do_read_metric_xsv(reader, row, col)
 
     def _read_metric(self, path, typ=None, xpath=None):
         ret = None
@@ -1137,7 +1154,7 @@ class Project(object):
                     if os.path.isdir(path):
                         logger.warning(
                             "Path '{path}' is a directory. "
-                            "Consider runnig with '-R'.".format(path=path)
+                            "Consider running with '-R'.".format(path=path)
                         )
                         return {}
 
@@ -1182,11 +1199,10 @@ class Project(object):
             return res
 
         if path and os.path.isdir(path):
-            msg = "file '{}' does not exist".format(path)
             return res
 
         if path:
-            msg = "file '{}' does not exist".format(path)
+            msg = "file '{}' does not exist or malformed".format(path)
         else:
             msg = (
                 "no metric files in this repository."
@@ -1215,10 +1231,6 @@ class Project(object):
             msg = "output '{}' scheme '{}' is not supported for metrics"
             raise DvcException(msg.format(out.path, out.path_info["scheme"]))
 
-        if out.use_cache:
-            msg = "cached output '{}' is not supported for metrics"
-            raise DvcException(msg.format(out.rel_path))
-
         if typ:
             if not isinstance(out.metric, dict):
                 out.metric = {}
@@ -1366,7 +1378,8 @@ class Project(object):
             stages.extend(list(nx.get_node_attributes(G, "stage").values()))
         return stages
 
-    def _welcome_message(self):
+    @staticmethod
+    def _welcome_message():
         import colorama
 
         logger.box(
@@ -1390,7 +1403,8 @@ class Project(object):
             )
         )
 
-    def _expand_target_path(self, from_path, to_path):
+    @staticmethod
+    def _expand_target_path(from_path, to_path):
         if os.path.isdir(to_path) and not os.path.isdir(from_path):
             return os.path.join(to_path, os.path.basename(from_path))
         return to_path
diff --git a/dvc/prompt.py b/dvc/prompt.py
index 6853ce40b..898eb921b 100644
--- a/dvc/prompt.py
+++ b/dvc/prompt.py
@@ -36,7 +36,7 @@ def confirm(statement):
     """Ask the user for confirmation about the specified statement.
 
     Args:
-        statement (str): statement to ask the user confirmation about.
+        statement (unicode): statement to ask the user confirmation about.
 
     Returns:
         bool: whether or not specified statement was confirmed.
diff --git a/dvc/stage.py b/dvc/stage.py
index 8f20d0bd3..8e885befc 100644
--- a/dvc/stage.py
+++ b/dvc/stage.py
@@ -116,11 +116,16 @@ class Stage(object):
         path=None,
         cmd=None,
         cwd=os.curdir,
-        deps=[],
-        outs=[],
+        deps=None,
+        outs=None,
         md5=None,
         locked=False,
     ):
+        if deps is None:
+            deps = []
+        if outs is None:
+            outs = []
+
         self.project = project
         self.path = path
         self.cmd = cmd
@@ -342,10 +347,11 @@ class Stage(object):
     def create(
         project=None,
         cmd=None,
-        deps=[],
-        outs=[],
-        outs_no_cache=[],
-        metrics_no_cache=[],
+        deps=None,
+        outs=None,
+        outs_no_cache=None,
+        metrics=None,
+        metrics_no_cache=None,
         fname=None,
         cwd=os.curdir,
         locked=False,
@@ -355,9 +361,23 @@ class Stage(object):
         remove_outs=False,
     ):
 
+        if outs is None:
+            outs = []
+        if deps is None:
+            deps = []
+        if outs_no_cache is None:
+            outs_no_cache = []
+        if metrics is None:
+            metrics = []
+        if metrics_no_cache is None:
+            metrics_no_cache = []
+
         stage = Stage(project=project, cwd=cwd, cmd=cmd, locked=locked)
 
         stage.outs = output.loads_from(stage, outs, use_cache=True)
+        stage.outs += output.loads_from(
+            stage, metrics, use_cache=True, metric=True
+        )
         stage.outs += output.loads_from(stage, outs_no_cache, use_cache=False)
         stage.outs += output.loads_from(
             stage, metrics_no_cache, use_cache=False, metric=True
@@ -512,7 +532,8 @@ class Stage(object):
         if any(missing):
             raise MissingDep(missing)
 
-    def _warn_if_fish(self, executable):  # pragma: no cover
+    @staticmethod
+    def _warn_if_fish(executable):  # pragma: no cover
         if (
             executable is None
             or os.path.basename(os.path.realpath(executable)) != "fish"
@@ -530,8 +551,8 @@ class Stage(object):
     def _check_circular_dependency(self):
         from dvc.exceptions import CircularDependencyError
 
-        circular_dependencies = set(file.path for file in self.deps) & set(
-            file.path for file in self.outs
+        circular_dependencies = set(d.path for d in self.deps) & set(
+            o.path for o in self.outs
         )
 
         if circular_dependencies:
@@ -541,11 +562,11 @@ class Stage(object):
         from dvc.exceptions import ArgumentDuplicationError
         from collections import Counter
 
-        count = Counter(file.path for file in self.deps + self.outs)
+        path_counts = Counter(edge.path for edge in self.deps + self.outs)
 
-        for file, occurrence in count.items():
+        for path, occurrence in path_counts.items():
             if occurrence > 1:
-                raise ArgumentDuplicationError(file)
+                raise ArgumentDuplicationError(path)
 
     def _run(self):
         self._check_missing_deps()
@@ -619,7 +640,8 @@ class Stage(object):
         for out in self.outs:
             out.checkout(force=force)
 
-    def _status(self, entries, name):
+    @staticmethod
+    def _status(entries, name):
         ret = {}
 
         for entry in entries:
diff --git a/tests/__main__.py b/tests/__main__.py
index 9612fa198..ab9e891e0 100644
--- a/tests/__main__.py
+++ b/tests/__main__.py
@@ -1,6 +1,8 @@
 import os
+import sys
 from subprocess import check_call
 
+
 REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 os.chdir(REPO_ROOT)
 
@@ -10,8 +12,14 @@ os.putenv(
 os.putenv("DVC_HOME", REPO_ROOT)
 os.putenv("DVC_TEST", "true")
 
+if len(sys.argv) == 1:
+    scope = "--all-modules"
+else:
+    scope = " ".join(sys.argv[1:])
+
 cmd = (
     "nosetests -v --processes=-1 --process-timeout=500 --cover-inclusive "
-    "--cover-erase --cover-package=dvc --with-coverage --all-modules --with-flaky"
+    "--cover-erase --cover-package=dvc --with-coverage --with-flaky "
+    "{scope} ".format(scope=scope)
 )
 check_call(cmd, shell=True)
diff --git a/tests/test_metrics.py b/tests/test_metrics.py
index c76704518..77ff4e355 100644
--- a/tests/test_metrics.py
+++ b/tests/test_metrics.py
@@ -359,7 +359,7 @@ class TestNoMetrics(TestDvc):
 
 
 class TestCachedMetrics(TestDvc):
-    def _do_write(self, branch):
+    def _do_add(self, branch):
         self.dvc.scm.checkout(branch)
         self.dvc.checkout(force=True)
 
@@ -369,20 +369,45 @@ class TestCachedMetrics(TestDvc):
         stages = self.dvc.add("metrics.json")
         self.assertEqual(len(stages), 1)
         stage = stages[0]
-        self.assertNotEqual(stage, None)
+        self.assertIsNotNone(stage)
 
         self.dvc.scm.add([".gitignore", "metrics.json.dvc"])
         self.dvc.scm.commit(branch)
 
-    def test(self):
+    def _do_run(self, branch):
+        self.dvc.scm.checkout(branch)
+        self.dvc.checkout(force=True)
+
+        with open("code.py", "w+") as fobj:
+            fobj.write("import sys\n")
+            fobj.write("import os\n")
+            fobj.write("import json\n")
+            fobj.write(
+                'print(json.dumps({{"metrics": "{branch}"}}))\n'.format(
+                    branch=branch
+                )
+            )
+
+        stage = self.dvc.run(
+            deps=["code.py"],
+            metrics=["metrics.json"],
+            cmd="python code.py metrics.json > metrics.json",
+        )
+        self.assertIsNotNone(stage)
+        self.assertEqual(stage.relpath, "metrics.json.dvc")
+
+        self.dvc.scm.add([".gitignore", "metrics.json.dvc"])
+        self.dvc.scm.commit(branch)
+
+    def _test_metrics(self, func):
         self.dvc.scm.commit("init")
 
         self.dvc.scm.branch("one")
         self.dvc.scm.branch("two")
 
-        self._do_write("master")
-        self._do_write("one")
-        self._do_write("two")
+        func("master")
+        func("one")
+        func("two")
 
         self.dvc = Project(".")
 
@@ -398,3 +423,9 @@ class TestCachedMetrics(TestDvc):
                 "two": {"metrics.json": ["two"]},
             },
         )
+
+    def test_add(self):
+        self._test_metrics(self._do_add)
+
+    def test_run(self):
+        self._test_metrics(self._do_run)
diff --git a/tests/test_run.py b/tests/test_run.py
index d68ce88de..97d979f28 100644
--- a/tests/test_run.py
+++ b/tests/test_run.py
@@ -50,7 +50,7 @@ class TestRun(TestDvc):
         self.assertTrue(stage.path, fname)
 
         with self.assertRaises(OutputDuplicationError):
-            stage = self.dvc.run(
+            self.dvc.run(
                 cmd=cmd,
                 deps=deps,
                 outs=outs,
@@ -530,6 +530,18 @@ class TestCmdRunOverwrite(TestDvc):
         self.assertNotEqual(stage_mtime, os.path.getmtime("out.dvc"))
 
 
+class TestCmdRunCliMetrics(TestDvc):
+    def test_cached(self):
+        ret = main(["run", "-m", "metrics.txt", "echo test > metrics.txt"])
+        self.assertEqual(ret, 0)
+        self.assertEqual(open("metrics.txt", "r").read().rstrip(), "test")
+
+    def test_not_cached(self):
+        ret = main(["run", "-M", "metrics.txt", "echo test > metrics.txt"])
+        self.assertEqual(ret, 0)
+        self.assertEqual(open("metrics.txt", "r").read().rstrip(), "test")
+
+
 class TestRunDeterministicBase(TestDvc):
     def setUp(self):
         super(TestRunDeterministicBase, self).setUp()