run: add --no-exec option

Fixes #385

Signed-off-by: Ruslan Kuprieiev <[email protected]>

dvc/cli.py

@@ -113,6 +113,11 @@ def parse_args(argv=None):
                         '--cwd',
                         default=os.path.curdir,
                         help='Directory to run your command and place state file in')
+    run_parser.add_argument(
+                        '--no-exec',
+                        action='store_true',
+                        default=False,
+                        help="Only create stage file without actually running it")
     run_parser.add_argument(
                         'command',
                         nargs=argparse.REMAINDER,

dvc/command/run.py

@@ -3,19 +3,26 @@ import os
 from dvc.command.common.base import CmdBase
 from dvc.logger import Logger
 from dvc.stage import Stage
+from dvc.exceptions import DvcException
 
 
 class CmdRun(CmdBase):
     def run(self):
         fname = self.stage_file_name(self.args.file, self.args.outs, self.args.outs_no_cache)
 
-        self.project.run(cmd=' '.join(self.args.command),
-                         outs=self.args.outs,
-                         outs_no_cache=self.args.outs_no_cache,
-                         deps=self.args.deps,
-                         locked=self.args.lock,
-                         fname=fname,
-                         cwd=self.args.cwd)
+        try:
+            self.project.run(cmd=' '.join(self.args.command),
+                             outs=self.args.outs,
+                             outs_no_cache=self.args.outs_no_cache,
+                             deps=self.args.deps,
+                             locked=self.args.lock,
+                             fname=fname,
+                             cwd=self.args.cwd,
+                             no_exec=self.args.no_exec)
+        except DvcException as ex:
+            self.project.logger.error('Failed to run command: {}'.format(str(ex)))
+            return 1
+
         return 0
 
     @staticmethod

dvc/project.py

@@ -145,7 +145,8 @@ class Project(object):
             outs_no_cache=[],
             locked=False,
             fname=Stage.STAGE_FILE,
-            cwd=os.curdir):
+            cwd=os.curdir,
+            no_exec=False):
         cwd = os.path.abspath(cwd)
         path = os.path.join(cwd, fname)
         outputs = Output.loads_from(self, outs, use_cache=True, cwd=cwd)
@@ -159,7 +160,8 @@ class Project(object):
                       outs=outputs,
                       deps=deps,
                       locked=locked)
-        stage.run()
+        if not no_exec:
+            stage.run()
         stage.dump()
         return stage
 

tests/test_run.py

@@ -45,3 +45,10 @@ class TestRunEmpty(TestDvc):
                      locked=False,
                      fname='empty.dvc',
                      cwd=os.curdir)
+
+
+class TestRunNoExec(TestDvc):
+    def test(self):
+        self.dvc.run(cmd='python {} {} {}'.format(self.CODE, self.FOO, 'out'),
+                     no_exec=True)
+        self.assertFalse(os.path.exists('out'))