Tui 1.0

* Move the updater into another process.
  This removes the limitation that caused Tui to crash with active workflows.
  Closes cylc#3527
* Add multi-workflow capability.
  Closes cylc#3464
* Add visual regression testing framework.
  Closes cylc#3530

cylc/flow/option_parsers.py

@@ -44,6 +44,7 @@
 )
 
 WORKFLOW_ID_ARG_DOC = ('WORKFLOW', 'Workflow ID')
+OPT_WORKFLOW_ID_ARG_DOC = ('[WORKFLOW]', 'Workflow ID')
 WORKFLOW_ID_MULTI_ARG_DOC = ('WORKFLOW ...', 'Workflow ID(s)')
 WORKFLOW_ID_OR_PATH_ARG_DOC = ('WORKFLOW | PATH', 'Workflow ID or path')
 ID_MULTI_ARG_DOC = ('ID ...', 'Workflow/Cycle/Family/Task ID(s)')

cylc/flow/scripts/tui.py

@@ -15,30 +15,35 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-"""cylc tui WORKFLOW
+"""cylc tui [WORKFLOW]
 
 View and control running workflows in the terminal.
 
 (Tui = Terminal User Interface)
 
-WARNING: Tui is experimental and may break with large flows.
-An upcoming change to the way Tui receives data from the scheduler will make it
-much more efficient in the future.
+Tui allows you to monitor and interact with workflows in a manner similar
+to the GUI.
+
+Press "h" whilst running Tui to bring up the help screen, use the arrow
+keys to navigage.
+
 """
-# TODO: remove this warning once Tui is delta-driven
-# https://github.com/cylc/cylc-flow/issues/3527
 
+from getpass import getuser
 from textwrap import indent
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 from urwid import html_fragment
 
+from cylc.flow.exceptions import InputError
+from cylc.flow.id import Tokens
 from cylc.flow.id_cli import parse_id
 from cylc.flow.option_parsers import (
-    WORKFLOW_ID_ARG_DOC,
+    OPT_WORKFLOW_ID_ARG_DOC,
     CylcOptionParser as COP,
 )
 from cylc.flow.terminal import cli_function
 from cylc.flow.tui import TUI
+from cylc.flow.tui.util import suppress_logging
 from cylc.flow.tui.app import (
     TuiApp,
     TREE_EXPAND_DEPTH
@@ -55,7 +60,7 @@
 def get_option_parser() -> COP:
     parser = COP(
         __doc__,
-        argdoc=[WORKFLOW_ID_ARG_DOC],
+        argdoc=[OPT_WORKFLOW_ID_ARG_DOC],
         # auto_add=False,  NOTE: at present auto_add can not be turned off
         color=False
     )
@@ -80,32 +85,58 @@ def get_option_parser() -> COP:
         action='store',
         default='80,24'
     )
+    parser.add_option(
+        '--single-workflow', '-s',
+        help=(
+            'Only show a single workflow rather than all workflows'
+        ),
+        action='store_true',
+        default=False,
+    )
 
     return parser
 
 
-@cli_function(get_option_parser)
-def main(_, options: 'Values', workflow_id: str) -> None:
-    workflow_id, *_ = parse_id(
-        workflow_id,
-        constraint='workflows',
+def configure_screenshot(v_term_size):
+    screen = html_fragment.HtmlGenerator()
+    screen.set_terminal_properties(256)
+    screen.register_palette(TuiApp.palette)
+    html_fragment.screenshot_init(
+        [tuple(map(int, v_term_size.split(',')))],
+        []
     )
+    return screen, html_fragment
+
+
+@cli_function(get_option_parser)
+def main(_, options: 'Values', workflow_id: Optional[str] = None) -> None:
+    if options.single_workflow and not workflow_id:
+        raise InputError('--single-workflow requires a workflow ID')
+
+    # get workflow ID if specified
+    if workflow_id:
+        workflow_id, *_ = parse_id(
+            workflow_id,
+            constraint='workflows',
+        )
+        tokens = Tokens(workflow_id)
+        workflow_id = tokens.duplicate(user=getuser()).id
+
+    # configure Tui
     screen = None
+    html_fragment = None
     if options.display == 'html':
-        TREE_EXPAND_DEPTH[0] = -1  # expand tree fully
-        screen = html_fragment.HtmlGenerator()
-        screen.set_terminal_properties(256)
-        screen.register_palette(TuiApp.palette)
-        html_fragment.screenshot_init(
-            [tuple(map(int, options.v_term_size.split(',')))],
-            []
-        )
+        screen, html_fragment = configure_screenshot(options.v_term_size)
 
+    # start Tui
     try:
-        TuiApp(workflow_id, screen=screen).main()
+        with suppress_logging():
+            TuiApp(screen=screen).main(
+                workflow_id,
+                options.single_workflow,
+            )
 
         if options.display == 'html':
-            for fragment in html_fragment.screenshot_collect():
-                print(fragment)
+            print(html_fragment.screenshot_collect()[-1])
     except KeyboardInterrupt:
         pass

cylc/flow/tui/__init__.py

@@ -143,6 +143,3 @@ def list_groups(self):
                     if binding['group'] == name
                 ]
             )
-
-
-BINDINGS = Bindings()