Experiments proof of concept (iterative#4199)

* experiments: add initial experiments.show

* only includes metrics + params (no code/data information)

* experiments: basic `dvc experiments show` functionality

* experiments: clone and run repro inside clone workspace

* repro: add -e/--experiment option

* experiments: hash experiments to identify duplicates

* experiments: update show

* experiments: checkout experiment after running repro

* experiments: add `dvc experiments checkout`

* experiments: add simple `dvc experiments diff` command

* just shows combined output from `metrics diff` and `plots diff` for
  now

* add very simple tests

* add some useful output messages

* experiments: suppress help messages while feature is in development

* experiment related commands will be accessible but hidden from the
  default command help messages

* add simple experiments command tests

* experiments: disable feature by default

* experiments only enabled in test environment (DVC_TEST) or when
  core.experiments config option is true

* use fetch on checkout missing revs

.dvc/.gitignore

@@ -9,3 +9,4 @@
 /pkg
 /repos
 /tmp
+/experiments

dvc/cli.py

@@ -15,6 +15,7 @@
     data_sync,
     destroy,
     diff,
+    experiments,
     freeze,
     gc,
     get,
@@ -77,6 +78,7 @@
     update,
     git_hook,
     plots,
+    experiments,
 ]
 
 

dvc/command/experiments.py

@@ -0,0 +1,358 @@
+import argparse
+import io
+import logging
+from collections import OrderedDict
+
+from dvc.command.base import CmdBase, append_doc_link, fix_subparsers
+from dvc.command.metrics import DEFAULT_PRECISION
+from dvc.exceptions import DvcException
+
+logger = logging.getLogger(__name__)
+
+
+def _update_names(names, items):
+    from flatten_json import flatten
+
+    for name, item in items:
+        if isinstance(item, dict):
+            item = flatten(item, ".")
+            names.update(item.keys())
+        else:
+            names.add(name)
+
+
+def _collect_names(all_experiments):
+    metric_names = set()
+    param_names = set()
+
+    for _, experiments in all_experiments.items():
+        for exp in experiments.values():
+            _update_names(metric_names, exp.get("metrics", {}).items())
+            _update_names(param_names, exp.get("params", {}).items())
+
+    return sorted(metric_names), sorted(param_names)
+
+
+def _collect_rows(
+    base_rev, experiments, metric_names, param_names, precision=None
+):
+    from flatten_json import flatten
+
+    if precision is None:
+        precision = DEFAULT_PRECISION
+
+    def _round(val):
+        if isinstance(val, float):
+            return round(val, precision)
+
+        return val
+
+    def _extend(row, names, items):
+        for fname, item in items:
+            if isinstance(item, dict):
+                item = flatten(item, ".")
+            else:
+                item = {fname: item}
+            for name in names:
+                if name in item:
+                    row.append(str(_round(item[name])))
+                else:
+                    row.append("-")
+
+    for i, (rev, exp) in enumerate(experiments.items()):
+        row = []
+        style = None
+        if rev == "baseline":
+            row.append(f"{base_rev}")
+            style = "bold"
+        elif i < len(experiments) - 1:
+            row.append(f"├── {rev[:7]}")
+        else:
+            row.append(f"└── {rev[:7]}")
+
+        _extend(row, metric_names, exp.get("metrics", {}).items())
+        _extend(row, param_names, exp.get("params", {}).items())
+
+        yield row, style
+
+
+def _show_experiments(all_experiments, console, precision=None):
+    from rich.table import Table
+    from dvc.scm.git import Git
+
+    metric_names, param_names = _collect_names(all_experiments)
+
+    table = Table(row_styles=["white", "bright_white"])
+    table.add_column("Experiment", header_style="black on grey93")
+    for name in metric_names:
+        table.add_column(
+            name, justify="right", header_style="black on cornsilk1"
+        )
+    for name in param_names:
+        table.add_column(
+            name, justify="left", header_style="black on light_cyan1"
+        )
+
+    for base_rev, experiments in all_experiments.items():
+        if Git.is_sha(base_rev):
+            base_rev = base_rev[:7]
+
+        for row, style, in _collect_rows(
+            base_rev,
+            experiments,
+            metric_names,
+            param_names,
+            precision=precision,
+        ):
+            table.add_row(*row, style=style)
+
+    console.print(table)
+
+
+class CmdExperimentsShow(CmdBase):
+    def run(self):
+        from rich.console import Console
+        from dvc.utils.pager import pager
+
+        if not self.repo.experiments:
+            return 0
+
+        try:
+            all_experiments = self.repo.experiments.show(
+                all_branches=self.args.all_branches,
+                all_tags=self.args.all_tags,
+                all_commits=self.args.all_commits,
+            )
+
+            # Note: rich does not currently include a native way to force
+            # infinite width for use with a pager
+            console = Console(
+                file=io.StringIO(), force_terminal=True, width=9999
+            )
+
+            _show_experiments(all_experiments, console)
+
+            pager(console.file.getvalue())
+        except DvcException:
+            logger.exception("failed to show experiments")
+            return 1
+
+        return 0
+
+
+class CmdExperimentsCheckout(CmdBase):
+    def run(self):
+        if not self.repo.experiments:
+            return 0
+
+        self.repo.experiments.checkout(
+            self.args.experiment, force=self.args.force
+        )
+
+        return 0
+
+
+def _show_diff(
+    diff, title="", markdown=False, no_path=False, old=False, precision=None
+):
+    from dvc.utils.diff import table
+
+    if precision is None:
+        precision = DEFAULT_PRECISION
+
+    def _round(val):
+        if isinstance(val, float):
+            return round(val, precision)
+
+        return val
+
+    rows = []
+    for fname, diff_ in diff.items():
+        sorted_diff = OrderedDict(sorted(diff_.items()))
+        for item, change in sorted_diff.items():
+            row = [] if no_path else [fname]
+            row.append(item)
+            if old:
+                row.append(_round(change.get("old")))
+            row.append(_round(change["new"]))
+            row.append(_round(change.get("diff", "diff not supported")))
+            rows.append(row)
+
+    header = [] if no_path else ["Path"]
+    header.append(title)
+    if old:
+        header.extend(["Old", "New"])
+    else:
+        header.append("Value")
+    header.append("Change")
+
+    return table(header, rows, markdown)
+
+
+class CmdExperimentsDiff(CmdBase):
+    def run(self):
+        if not self.repo.experiments:
+            return 0
+
+        try:
+            diff = self.repo.experiments.diff(
+                a_rev=self.args.a_rev,
+                b_rev=self.args.b_rev,
+                all=self.args.all,
+            )
+
+            if self.args.show_json:
+                import json
+
+                logger.info(json.dumps(diff))
+            else:
+                diffs = [("metrics", "Metric"), ("params", "Param")]
+                for key, title in diffs:
+                    table = _show_diff(
+                        diff[key],
+                        title=title,
+                        markdown=self.args.show_md,
+                        no_path=self.args.no_path,
+                        old=self.args.old,
+                        precision=self.args.precision,
+                    )
+                    if table:
+                        logger.info(table)
+                        logger.info("")
+
+        except DvcException:
+            logger.exception("failed to show experiments diff")
+            return 1
+
+        return 0
+
+
+def add_parser(subparsers, parent_parser):
+    EXPERIMENTS_HELP = "Commands to display and compare experiments."
+
+    experiments_parser = subparsers.add_parser(
+        "experiments",
+        parents=[parent_parser],
+        description=append_doc_link(EXPERIMENTS_HELP, "experiments"),
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+
+    experiments_subparsers = experiments_parser.add_subparsers(
+        dest="cmd",
+        help="Use `dvc experiments CMD --help` to display "
+        "command-specific help.",
+    )
+
+    fix_subparsers(experiments_subparsers)
+
+    EXPERIMENTS_SHOW_HELP = "Print experiments."
+    experiments_show_parser = experiments_subparsers.add_parser(
+        "show",
+        parents=[parent_parser],
+        description=append_doc_link(EXPERIMENTS_SHOW_HELP, "experiments/show"),
+        help=EXPERIMENTS_SHOW_HELP,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    experiments_show_parser.add_argument(
+        "-a",
+        "--all-branches",
+        action="store_true",
+        default=False,
+        help="Show metrics for all branches.",
+    )
+    experiments_show_parser.add_argument(
+        "-T",
+        "--all-tags",
+        action="store_true",
+        default=False,
+        help="Show metrics for all tags.",
+    )
+    experiments_show_parser.add_argument(
+        "--all-commits",
+        action="store_true",
+        default=False,
+        help="Show metrics for all commits.",
+    )
+    experiments_show_parser.set_defaults(func=CmdExperimentsShow)
+
+    EXPERIMENTS_CHECKOUT_HELP = "Checkout experiments."
+    experiments_checkout_parser = experiments_subparsers.add_parser(
+        "checkout",
+        parents=[parent_parser],
+        description=append_doc_link(
+            EXPERIMENTS_CHECKOUT_HELP, "experiments/checkout"
+        ),
+        help=EXPERIMENTS_CHECKOUT_HELP,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    experiments_checkout_parser.add_argument(
+        "-f",
+        "--force",
+        action="store_true",
+        default=False,
+        help="Overwrite your current workspace with changes from the "
+        "experiment.",
+    )
+    experiments_checkout_parser.add_argument(
+        "experiment", help="Checkout this experiment.",
+    )
+    experiments_checkout_parser.set_defaults(func=CmdExperimentsCheckout)
+
+    EXPERIMENTS_DIFF_HELP = (
+        "Show changes between experiments in the DVC repository."
+    )
+    experiments_diff_parser = experiments_subparsers.add_parser(
+        "diff",
+        parents=[parent_parser],
+        description=append_doc_link(EXPERIMENTS_DIFF_HELP, "experiments/diff"),
+        help=EXPERIMENTS_DIFF_HELP,
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    experiments_diff_parser.add_argument(
+        "a_rev", nargs="?", help="Old experiment to compare (defaults to HEAD)"
+    )
+    experiments_diff_parser.add_argument(
+        "b_rev",
+        nargs="?",
+        help="New experiment to compare (defaults to the current workspace)",
+    )
+    experiments_diff_parser.add_argument(
+        "--all",
+        action="store_true",
+        default=False,
+        help="Show unchanged metrics/params as well.",
+    )
+    experiments_diff_parser.add_argument(
+        "--show-json",
+        action="store_true",
+        default=False,
+        help="Show output in JSON format.",
+    )
+    experiments_diff_parser.add_argument(
+        "--show-md",
+        action="store_true",
+        default=False,
+        help="Show tabulated output in the Markdown format (GFM).",
+    )
+    experiments_diff_parser.add_argument(
+        "--old",
+        action="store_true",
+        default=False,
+        help="Show old metric/param value.",
+    )
+    experiments_diff_parser.add_argument(
+        "--no-path",
+        action="store_true",
+        default=False,
+        help="Don't show metric/param path.",
+    )
+    experiments_diff_parser.add_argument(
+        "--precision",
+        type=int,
+        help=(
+            "Round metrics/params to `n` digits precision after the decimal "
+            f"point. Rounds to {DEFAULT_PRECISION} digits by default."
+        ),
+        metavar="<n>",
+    )
+    experiments_diff_parser.set_defaults(func=CmdExperimentsDiff)

dvc/command/repro.py

@@ -40,6 +40,7 @@ def run(self):
                     downstream=self.args.downstream,
                     recursive=self.args.recursive,
                     force_downstream=self.args.force_downstream,
+                    experiment=self.args.experiment,
                 )
 
                 if len(stages) == 0:
@@ -166,4 +167,11 @@ def add_parser(subparsers, parent_parser):
         default=False,
         help="Start from the specified stages when reproducing pipelines.",
     )
+    repro_parser.add_argument(
+        "-e",
+        "--experiment",
+        action="store_true",
+        default=False,
+        help=argparse.SUPPRESS,
+    )
     repro_parser.set_defaults(func=CmdRepro)