ENH: ls: Use pyout to render table

The main benefit of using pyout here is that we can query statuses
asynchronously, but it also allows us to style the output in more
complex ways (automatic truncation, coloring by regexp, ...) with less
custom code than we'd need otherwise.

This switch to pyout should not change how we interpret or update the
resource statuses, but the code for interacting with the resources is
a little more complicated because, when --refresh is given, we access
the resources in functions that are called asynchronously.  And to
update the resource statuses, we need to look at the values after the
asynchronous calls have returned.

Closes #318.

reproman/interface/ls.py

@@ -11,7 +11,9 @@
 
 __docformat__ = 'restructuredtext'
 
-from collections import OrderedDict
+from functools import partial
+
+from pyout import Tabular
 
 from .base import Interface
 # import reproman.interface.base  # Needed for test patching
@@ -55,50 +57,84 @@ class Ls(Interface):
 
     @staticmethod
     def __call__(resrefs=None, verbose=False, refresh=False):
-        id_length = 19  # todo: make it possible to output them long
-        template = '{:<20} {:<20} {:<%(id_length)s} {!s:<10}' % locals()
-        ui.message(template.format('RESOURCE NAME', 'TYPE', 'ID', 'STATUS'))
-        ui.message(template.format('-------------', '----', '--', '------'))
-
-        results = OrderedDict()
         manager = get_manager()
         if not resrefs:
             resrefs = (manager.inventory[n]["id"] for n in sorted(manager)
                        if not n.startswith("_"))
 
-        for resref in resrefs:
-            try:
-                resource = manager.get_resource(resref)
-                name = resource.name
-            except ResourceError as e:
-                lgr.warning("Manager did not return a resource for %s: %s",
-                            resref, exc_str(e))
-                continue
-
+        table = Tabular(
+            # Note: We're going with the name as the row key even though ID
+            # would be the more natural choice because (1) inventory already
+            # uses the name as the key, so we know it's unique and (2) sadly we
+            # can't rely on the ID saying set after a .connect() calls (e.g.,
+            # see docker_container.connect()).
+            ["name", "type", "id", "status"],
+            style={
+                "default_": {"width": {"marker": "…", "truncate": "center"}},
+                "header_": {"underline": True,
+                            "transform": str.upper},
+                "status": {"color":
+                           {"re_lookup": [["^running$", "green"],
+                                          ["^(stopped|exited)$", "red"],
+                                          ["(ERROR|NOT FOUND)", "red"]]},
+                           "bold":
+                           {"re_lookup": [["(ERROR|NOT FOUND)", True]]}}})
+
+        def get_status(res):
             if refresh:
+                def fn():
+                    try:
+                        res.connect()
+                    except Exception as e:
+                        status = 'CONNECTION ERROR'
+                    else:
+                        status = res.status if res.id else 'NOT FOUND'
+                    return status
+                return "querying…", fn
+            else:
+                return res.status
+
+        # Store a list of actions to do after the table is finalized so that we
+        # don't interrupt the table's output.
+        do_after = []
+        # The refresh happens in an asynchronous call. Keep a list of resources
+        # that we should ask pyout about once the table is finalized.
+        resources_to_refresh = []
+        with table:
+            for resref in resrefs:
                 try:
-                    resource.connect()
-                    if not resource.id:
-                        resource.status = 'NOT FOUND'
-                except Exception as e:
-                    lgr.debug("%s resource query error: %s", name, exc_str(e))
-                    resource.status = 'CONNECTION ERROR'
-
-                manager.inventory[name].update({'status': resource.status})
-
-            id_ = manager.inventory[name]['id']
-            msgargs = (
-                name,
-                resource.type,
-                id_[:id_length],
-                resource.status,
-            )
-            ui.message(template.format(*msgargs))
-            results[(name,)] = dict(zip(["name", "type", "id", "status"],
-                                        msgargs))
+                    resource = manager.get_resource(resref)
+                    name = resource.name
+                except ResourceError as e:
+                    do_after.append(
+                        partial(lgr.warning,
+                                "Manager did not return a resource for %s: %s",
+                                resref,
+                                exc_str(e)))
+                    continue
+
+                id_ = manager.inventory[name]['id']
+                assert id_ == resource.id, "bug in resource logic"
+                table([name,
+                       resource.type,
+                       id_,
+                       get_status(resource)])
+                resources_to_refresh.append(resource)
+
+        if do_after or not refresh:
+            # Distinguish between the table and added information.
+            ui.message("\n")
+
+        for fn in do_after:
+            fn()
 
         if refresh:
-            manager.save_inventory()
+            if resources_to_refresh:
+                for res in resources_to_refresh:
+                    name = res.name
+                    status = table[(name,)]["status"]
+                    manager.inventory[name].update({'status': status})
+                manager.save_inventory()
         else:
             ui.message('Use --refresh option to view updated status.')
-        return results
+        return table

reproman/interface/tests/test_ls.py

@@ -7,11 +7,14 @@
 # ## ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ##
 
 import contextlib
+from functools import partial
 from io import StringIO
 from unittest.mock import patch
 
 import pytest
 
+from pyout import Tabular
+
 from ...api import ls
 from ...resource.base import ResourceManager
 from ...tests.skip import skipif
@@ -56,15 +59,16 @@ def resource_manager():
 @pytest.fixture(scope="function")
 def ls_fn(resource_manager):
     stream = StringIO()
+    TestTabular = partial(Tabular, stream=stream)
 
     def fn(*args, **kwargs):
         skipif.no_docker_dependencies()
         with contextlib.ExitStack() as stack:
             stack.enter_context(patch("docker.Client"))
             stack.enter_context(patch("reproman.interface.ls.get_manager",
                                       return_value=resource_manager))
-            stack.enter_context(patch("reproman.interface.ls.ui._ui.out",
-                                      stream))
+            stack.enter_context(patch("reproman.interface.ls.Tabular",
+                                      TestTabular))
             return ls(*args, **kwargs), stream.getvalue()
     return fn