dvc: add support for dvc diff command

dvc/cli.py

@@ -32,6 +32,7 @@
 import dvc.command.daemon as daemon
 import dvc.command.commit as commit
 import dvc.command.tag as tag
+import dvc.command.diff as diff
 from dvc.exceptions import DvcParserError
 from dvc import VERSION
 
@@ -62,6 +63,7 @@
     daemon,
     commit,
     tag,
+    diff,
 ]
 
 

dvc/command/diff.py

@@ -0,0 +1,153 @@
+from __future__ import unicode_literals
+
+import humanize
+import inflect
+
+
+import dvc.logger as logger
+from dvc.exceptions import DvcException
+from dvc.command.base import CmdBase
+from dvc.utils.collections import compact
+import dvc.repo.diff as diff
+
+
+class CmdDiff(CmdBase):
+    def _print_size(self, size):
+        if size < 0:
+            change = "decreased by {}"
+        elif size > 0:
+            change = "increased by {}"
+        else:
+            change = "not changed"
+        natur_size = humanize.naturalsize(abs(size))
+        return change.format(natur_size)
+
+    def _get_md5_string(self, sign, file_name, checksum):
+        sample_msg = ""
+        if file_name:
+            sample_msg = "{}{} with md5 {}\n"
+            sample_msg = sample_msg.format(sign, file_name, checksum)
+        return sample_msg
+
+    def _get_dir_changes(self, dct):
+        engine = inflect.engine()
+        changes_msg = (
+            "{} {} not changed, {} {} modified, {} {} added, "
+            "{} {} deleted, size was {}"
+        )
+        changes_msg = changes_msg.format(
+            dct[diff.DIFF_IDENT],
+            engine.plural("file", dct[diff.DIFF_IDENT]),
+            dct[diff.DIFF_CHANGE],
+            engine.plural("file", dct[diff.DIFF_CHANGE]),
+            dct[diff.DIFF_NEW],
+            engine.plural("file", dct[diff.DIFF_NEW]),
+            dct[diff.DIFF_DEL],
+            engine.plural("file", dct[diff.DIFF_DEL]),
+            self._print_size(dct[diff.DIFF_SIZE]),
+        )
+        return changes_msg
+
+    def _get_file_changes(self, dct):
+        if (
+            dct.get(diff.DIFF_OLD_FILE)
+            and dct.get(diff.DIFF_NEW_FILE)
+            and dct[diff.DIFF_SIZE] == 0
+        ):
+            msg = "file size was not changed"
+        elif dct.get(diff.DIFF_NEW_FILE):
+            msg = "added file with size {}".format(
+                humanize.naturalsize(dct[diff.DIFF_SIZE])
+            )
+        elif dct.get(diff.DIFF_OLD_FILE):
+            msg = "deleted file with size {}".format(
+                humanize.naturalsize(abs(dct[diff.DIFF_SIZE]))
+            )
+        else:
+            msg = "file was modified, file size {}".format(
+                self._print_size(dct[diff.DIFF_SIZE])
+            )
+        return msg
+
+    def _get_royal_changes(self, dct):
+        if dct[diff.DIFF_SIZE] != diff.DIFF_SIZE_UNKNOWN:
+            if dct.get("is_dir"):
+                return self._get_dir_changes(dct)
+            else:
+                return self._get_file_changes(dct)
+        return "size is ?"
+
+    def _show(self, diff_dct):
+        msg = "dvc diff from {} to {}".format(
+            diff_dct[diff.DIFF_A_REF], diff_dct[diff.DIFF_B_REF]
+        )
+        if diff_dct.get(diff.DIFF_EQUAL):
+            logger.info(msg)
+            return
+        for dct in diff_dct[diff.DIFF_LIST]:
+            msg += "\n\ndiff for '{}'\n".format(dct[diff.DIFF_TARGET])
+            msg += self._get_md5_string(
+                "-",
+                dct.get(diff.DIFF_OLD_FILE),
+                dct.get(diff.DIFF_OLD_CHECKSUM),
+            )
+            msg += self._get_md5_string(
+                "+",
+                dct.get(diff.DIFF_NEW_FILE),
+                dct.get(diff.DIFF_NEW_CHECKSUM),
+            )
+            msg += "\n"
+            msg += self._get_royal_changes(dct)
+        logger.info(msg)
+        return msg
+
+    def run(self):
+        try:
+            msg = self.repo.diff(
+                self.args.a_ref, target=self.args.target, b_ref=self.args.b_ref
+            )
+            self._show(msg)
+        except DvcException:
+            msg = "failed to get 'diff {}'"
+            args = " ".join(
+                compact([self.args.target, self.args.a_ref, self.args.b_ref])
+            )
+            msg = msg.format(args)
+            logger.error(msg)
+            return 1
+        return 0
+
+
+def add_parser(subparsers, parent_parser):
+    description = (
+        "Show diff of a data file or a directory that "
+        "is under DVC control. Some basic statistics "
+        "summary, how many files were deleted/changed."
+    )
+    help = "Show a diff of a DVC controlled data file or a directory."
+    diff_parser = subparsers.add_parser(
+        "diff", parents=[parent_parser], description=description, help=help
+    )
+    diff_parser.add_argument(
+        "-t",
+        "--target",
+        default=None,
+        help=(
+            "Source path to a data file or directory. Default None,"
+            "If not specified, compares all files and directories "
+            "that are under DVC control in the current working space."
+        ),
+    )
+    diff_parser.add_argument(
+        "a_ref", help="Git reference from which diff calculates"
+    )
+    diff_parser.add_argument(
+        "b_ref",
+        help=(
+            "Git reference till which diff calculates, if omitted "
+            "diff shows the difference between current HEAD and a_ref"
+        ),
+        nargs="?",
+        default=None,
+    )
+    diff_parser.set_defaults(func=CmdDiff)

dvc/repo/__init__.py

@@ -33,6 +33,7 @@ class Repo(object):
     from dvc.repo.gc import gc
     from dvc.repo.commit import commit
     from dvc.repo.pkg import install_pkg
+    from dvc.repo.diff import diff
     from dvc.repo.brancher import brancher
 
     def __init__(self, root_dir=None):