dvc: introduce dvc params diff

Fixes iterative#3528

dvc/cli.py

@@ -23,6 +23,7 @@
     ls,
     lock,
     metrics,
+    params,
     move,
     pipeline,
     remote,
@@ -62,6 +63,7 @@
     remote,
     cache,
     metrics,
+    params,
     install,
     root,
     ls,

dvc/command/metrics.py

@@ -114,21 +114,9 @@ def run(self):
 
 
 def _show_diff(diff):
-    from texttable import Texttable
+    from dvc.utils.diff import table
 
-    if not diff:
-        return ""
-
-    table = Texttable()
-
-    # disable automatic formatting
-    table.set_cols_dtype(["t", "t", "t", "t"])
-
-    # remove borders to make it easier for users to copy stuff
-    table.set_chars(("", "", "", ""))
-    table.set_deco(0)
-
-    rows = [["Path", "Metric", "Value", "Change"]]
+    rows = []
     for fname, mdiff in diff.items():
         for metric, change in mdiff.items():
             rows.append(
@@ -139,8 +127,8 @@ def _show_diff(diff):
                     change.get("diff", "diff not supported"),
                 ]
             )
-    table.add_rows(rows)
-    return table.draw()
+
+    return table(["Path", "Metric", "Value", "Change"], rows)
 
 
 class CmdMetricsDiff(CmdBase):
@@ -160,7 +148,9 @@ def run(self):
 
                 logger.info(json.dumps(diff))
             else:
-                logger.info(_show_diff(diff))
+                table = _show_diff(diff)
+                if table:
+                    logger.info(table)
 
         except DvcException:
             logger.exception("failed to show metrics diff")

dvc/command/params.py

@@ -0,0 +1,90 @@
+import argparse
+import logging
+
+from dvc.command.base import append_doc_link
+from dvc.command.base import CmdBase
+from dvc.command.base import fix_subparsers
+from dvc.exceptions import DvcException
+
+
+logger = logging.getLogger(__name__)
+
+
+def _show_diff(diff):
+    from dvc.utils.diff import table
+
+    rows = []
+    for fname, mdiff in diff.items():
+        for param, change in mdiff.items():
+            rows.append([fname, param, change["old"], change["new"]])
+
+    return table(["Path", "Param", "Old", "New"], rows)
+
+
+class CmdParamsDiff(CmdBase):
+    def run(self):
+        try:
+            diff = self.repo.params.diff(
+                a_rev=self.args.a_rev, b_rev=self.args.b_rev,
+            )
+
+            if self.args.show_json:
+                import json
+
+                logger.info(json.dumps(diff))
+            else:
+                table = _show_diff(diff)
+                if table:
+                    logger.info(table)
+
+        except DvcException:
+            logger.exception("failed to show params diff")
+            return 1
+
+        return 0
+
+
+def add_parser(subparsers, parent_parser):
+    PARAMS_HELP = "Commands to display params."
+
+    params_parser = subparsers.add_parser(
+        "params",
+        parents=[parent_parser],
+        description=append_doc_link(PARAMS_HELP, "params"),
+        help=PARAMS_HELP,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+
+    params_subparsers = params_parser.add_subparsers(
+        dest="cmd",
+        help="Use `dvc params CMD --help` to display command-specific help.",
+    )
+
+    fix_subparsers(params_subparsers)
+
+    PARAMS_DIFF_HELP = (
+        "Show changes in params between commits in the DVC repository, or "
+        "between a commit and the workspace."
+    )
+    params_diff_parser = params_subparsers.add_parser(
+        "diff",
+        parents=[parent_parser],
+        description=append_doc_link(PARAMS_DIFF_HELP, "params/diff"),
+        help=PARAMS_DIFF_HELP,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    params_diff_parser.add_argument(
+        "a_rev", nargs="?", help="Old Git commit to compare (defaults to HEAD)"
+    )
+    params_diff_parser.add_argument(
+        "b_rev",
+        nargs="?",
+        help=("New Git commit to compare (defaults to the current workspace)"),
+    )
+    params_diff_parser.add_argument(
+        "--show-json",
+        action="store_true",
+        default=False,
+        help="Show output in JSON format.",
+    )
+    params_diff_parser.set_defaults(func=CmdParamsDiff)

dvc/dependency/param.py

@@ -52,7 +52,7 @@ def status(self):
             return status
 
         status = defaultdict(dict)
-        info = self._get_info()
+        info = self.read_params()
         for param in self.params:
             if param not in info.keys():
                 st = "deleted"
@@ -74,7 +74,7 @@ def dumpd(self):
             self.PARAM_PARAMS: self.info or self.params,
         }
 
-    def _get_info(self):
+    def read_params(self):
         if not self.exists:
             return {}
 
@@ -95,7 +95,7 @@ def _get_info(self):
         return ret
 
     def save_info(self):
-        info = self._get_info()
+        info = self.read_params()
 
         missing_params = set(self.params) - set(info.keys())
         if missing_params:

dvc/repo/__init__.py

@@ -67,6 +67,7 @@ def __init__(self, root_dir=None):
         from dvc.cache import Cache
         from dvc.data_cloud import DataCloud
         from dvc.repo.metrics import Metrics
+        from dvc.repo.params import Params
         from dvc.scm.tree import WorkingTree
         from dvc.repo.tag import Tag
         from dvc.utils.fs import makedirs
@@ -102,6 +103,7 @@ def __init__(self, root_dir=None):
         self.cloud = DataCloud(self)
 
         self.metrics = Metrics(self)
+        self.params = Params(self)
         self.tag = Tag(self)
 
         self._ignore()

dvc/repo/metrics/diff.py

@@ -1,80 +1,7 @@
-import json
-from collections import defaultdict
-
-from flatten_json import flatten
-
+import dvc.utils.diff
 from dvc.exceptions import NoMetricsError
 
 
-def _parse(raw):
-    if raw is None or isinstance(raw, (dict, list, int, float)):
-        return raw
-
-    assert isinstance(raw, str)
-    try:
-        return json.loads(raw)
-    except json.JSONDecodeError:
-        return raw
-
-
-def _diff_vals(old, new):
-    if (
-        isinstance(new, list)
-        and isinstance(old, list)
-        and len(old) == len(new) == 1
-    ):
-        return _diff_vals(old[0], new[0])
-
-    if old == new:
-        return {}
-
-    res = {"old": old, "new": new}
-    if isinstance(new, (int, float)) and isinstance(old, (int, float)):
-        res["diff"] = new - old
-    return res
-
-
-def _flatten(d):
-    if not d:
-        return defaultdict(lambda: None)
-
-    if isinstance(d, dict):
-        return defaultdict(lambda: None, flatten(d, "."))
-
-    return defaultdict(lambda: "unable to parse")
-
-
-def _diff_dicts(old_dict, new_dict):
-    new = _flatten(new_dict)
-    old = _flatten(old_dict)
-
-    res = defaultdict(dict)
-
-    xpaths = set(old.keys())
-    xpaths.update(set(new.keys()))
-    for xpath in xpaths:
-        old_val = old[xpath]
-        new_val = new[xpath]
-        val_diff = _diff_vals(old_val, new_val)
-        if val_diff:
-            res[xpath] = val_diff
-    return dict(res)
-
-
-def _diff(old_raw, new_raw):
-    old = _parse(old_raw)
-    new = _parse(new_raw)
-
-    if isinstance(new, dict) or isinstance(old, dict):
-        return _diff_dicts(old, new)
-
-    val_diff = _diff_vals(old, new)
-    if val_diff:
-        return {"": val_diff}
-
-    return {}
-
-
 def _get_metrics(repo, *args, rev=None, **kwargs):
     try:
         metrics = repo.metrics.show(
@@ -89,12 +16,4 @@ def diff(repo, *args, a_rev=None, b_rev=None, **kwargs):
     old = _get_metrics(repo, *args, **kwargs, rev=(a_rev or "HEAD"))
     new = _get_metrics(repo, *args, **kwargs, rev=b_rev)
 
-    paths = set(old.keys())
-    paths.update(set(new.keys()))
-
-    res = defaultdict(dict)
-    for path in paths:
-        path_diff = _diff(old.get(path), new.get(path))
-        if path_diff:
-            res[path] = path_diff
-    return dict(res)
+    return dvc.utils.diff.diff(old, new)

dvc/repo/params/__init__.py

@@ -0,0 +1,13 @@
+class Params(object):
+    def __init__(self, repo):
+        self.repo = repo
+
+    def show(self, *args, **kwargs):
+        from .show import show
+
+        return show(self.repo, *args, **kwargs)
+
+    def diff(self, *args, **kwargs):
+        from .diff import diff
+
+        return diff(self.repo, *args, **kwargs)

dvc/repo/params/diff.py

@@ -0,0 +1,30 @@
+import dvc.utils.diff
+from .show import NoParamsError
+
+
+def _get_params(repo, *args, rev=None, **kwargs):
+    try:
+        params = repo.params.show(*args, **kwargs, revs=[rev] if rev else None)
+        return params.get(rev or "", {})
+    except NoParamsError:
+        return {}
+
+
+def _format(params):
+    ret = {}
+    for key, val in params.items():
+        if isinstance(val, dict):
+            new_val = _format(val)
+        elif isinstance(val, list):
+            new_val = str(val)
+        else:
+            new_val = val
+        ret[key] = new_val
+    return ret
+
+
+def diff(repo, *args, a_rev=None, b_rev=None, **kwargs):
+    old = _get_params(repo, *args, **kwargs, rev=(a_rev or "HEAD"))
+    new = _get_params(repo, *args, **kwargs, rev=b_rev)
+
+    return dvc.utils.diff.diff(_format(old), _format(new))