Add CYLC_ variables to empy globals; and tidy up.

cylc/flow/parsec/empysupport.py

@@ -24,6 +24,7 @@
 import typing as t
 
 from cylc.flow.parsec.exceptions import EmPyError
+from cylc.flow.parsec.fileparse import get_cylc_env_vars
 
 
 def empyprocess(
@@ -52,6 +53,12 @@ def empyprocess(
     ftempl = StringIO('\n'.join(flines))
     xtempl = StringIO()
     interpreter = em.Interpreter(output=em.UncloseableFile(xtempl))
+
+    # Add `CYLC_` environment variables to the global namespace.
+    interpreter.updateGlobals(
+        get_cylc_env_vars()
+    )
+
     try:
         interpreter.file(ftempl, '<template>', template_vars)
     except Exception as exc:

cylc/flow/parsec/fileparse.py

@@ -105,6 +105,27 @@
 )
 
 
+def get_cylc_env_vars() -> t.Dict[str, str]:
+    """Return a restricted dict of CYLC_ environment variables for templating.
+
+    The following variables are ignored because the do not necessarily reflect
+    the running code version (I might not use the "cylc" wrapper, or it might
+    select a different version):
+
+    CYLC_VERSION
+        Set as a template variable elsewhere, from the hardwired code version.
+
+    CYLC_ENV_NAME
+        Providing it as a template variable would just be misleading.
+    """
+    return {
+        key: val
+        for key, val in os.environ.items()
+        if key.startswith('CYLC_')
+        if key not in ["CYLC_VERSION", "CYLC_ENV_NAME"]
+    }
+
+
 def _concatenate(lines):
     """concatenate continuation lines"""
     index = 0
@@ -446,10 +467,9 @@ def read_and_proc(
         flines = inline(
             flines, fdir, fpath, viewcfg=viewcfg)
 
+    # Add the hardwired code version to template vars as CYLC_VERSION
     template_vars['CYLC_VERSION'] = __version__
-
     template_vars = merge_template_vars(template_vars, extra_vars)
-
     template_vars['CYLC_TEMPLATE_VARS'] = template_vars
 
     # Fail if templating_detected ≠ hashbang

cylc/flow/parsec/jinja2support.py

@@ -39,6 +39,7 @@
 
 from cylc.flow import LOG
 from cylc.flow.parsec.exceptions import Jinja2Error
+from cylc.flow.parsec.fileparse import get_cylc_env_vars
 
 TRACEBACK_LINENO = re.compile(
     r'\s+?File "(?P<file>.*)", line (?P<line>\d+), in .*template'
@@ -188,15 +189,13 @@ def jinja2environment(dir_=None):
     # Import WORKFLOW HOST USER ENVIRONMENT into template:
     # (Usage e.g.: {{environ['HOME']}}).
     env.globals['environ'] = os.environ
-
     env.globals['raise'] = raise_helper
     env.globals['assert'] = assert_helper
 
-    # And all `CYLC_` variables (this will include CYLC_WORKFLOW environment
-    # variables exported by `cylc` commands before config file parsing.
-    for key, val in os.environ.items():
-        if key.startswith('CYLC_'):
-            env.globals[key] = val
+    # Add `CYLC_` environment variables to the global namespace.
+    env.globals.update(
+        get_cylc_env_vars()
+    )
     return env
 
 
@@ -275,11 +274,11 @@ def jinja2process(
     # CALLERS SHOULD HANDLE JINJA2 TEMPLATESYNTAXERROR AND TEMPLATEERROR
     # AND TYPEERROR (e.g. for not using "|int" filter on number inputs.
     # Convert unicode to plain str, ToDo - still needed for parsec?)
-
     try:
         env = jinja2environment(dir_)
         template = env.from_string('\n'.join(flines[1:]))
         lines = str(template.render(template_vars)).splitlines()
+        print()
     except TemplateSyntaxError as exc:
         filename = None
         # extract source lines
@@ -306,16 +305,4 @@ def jinja2process(
             lines=get_error_lines(fpath, flines),
         )
 
-    flow_config = []
-    for line in lines:
-        # Jinja2 leaves blank lines where source lines contain
-        # only Jinja2 code; this matters if line continuation
-        # markers are involved, so we remove blank lines here.
-        if not line.strip():
-            continue
-            # restoring newlines here is only necessary for display by
-        # the cylc view command:
-        # ##flow_config.append(line + '\n')
-        flow_config.append(line)
-
-    return flow_config
+    return [line for line in lines if line.strip()]

cylc/flow/scripts/view.py

@@ -43,6 +43,7 @@
     CylcOptionParser as COP,
 )
 from cylc.flow.parsec.fileparse import read_and_proc
+from cylc.flow.templatevars import get_template_vars
 from cylc.flow.terminal import cli_function
 
 if TYPE_CHECKING:

tests/unit/test_config.py

@@ -15,6 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import sys
 from optparse import Values
 from typing import Any, Callable, Dict, List, Optional, Tuple, Type
 from pathlib import Path
@@ -34,7 +35,7 @@
     WorkflowConfigError,
     XtriggerConfigError,
 )
-from cylc.flow.parsec.exceptions import Jinja2Error
+from cylc.flow.parsec.exceptions import Jinja2Error, EmPyError
 from cylc.flow.scheduler_cli import RunOptions
 from cylc.flow.scripts.validate import ValidateOptions
 from cylc.flow.workflow_files import WorkflowFiles
@@ -1028,7 +1029,11 @@ def test_rsync_includes_will_not_accept_sub_directories(tmp_flow_config):
     ]
 )
 def test_jinja2_cylc_vars(tmp_flow_config, cylc_var, expected_err):
-    """Valid CYLC variables should be available to Jinja2 during parsing."""
+    """Defined CYLC_ variables should be available to Jinja2 during parsing.
+
+    This test is not located in the jinja2_support unit test module because
+    CYLC_ variables are only defined during workflow config parsing.
+    """
     reg = 'nodule'
     flow_file = tmp_flow_config(reg, """#!Jinja2
     # {{""" + cylc_var + """}}
@@ -1044,6 +1049,45 @@ def test_jinja2_cylc_vars(tmp_flow_config, cylc_var, expected_err):
         assert expected_err[1] in str(exc)
 
 
+@pytest.mark.parametrize(
+    'cylc_var, expected_err',
+    [
+        ["CYLC_WORKFLOW_NAME", None],
+        ["CYLC_BEEF_WELLINGTON", (EmPyError, "is not defined")],
+    ]
+)
+def test_empy_cylc_vars(tmp_flow_config, cylc_var, expected_err):
+    """Defined CYLC_ variables should be available to empy during parsing.
+
+    This test is not located in the empy_support unit test module because
+    CYLC_ variables are only defined during workflow config parsing.
+    """
+    reg = 'nodule'
+    flow_file = tmp_flow_config(reg, """#!empy
+    # @(""" + cylc_var + """)
+    [scheduler]
+        allow implicit tasks = True
+    [scheduling]
+        [[graph]]
+            R1 = foo
+    """)
+
+    # empy replaces sys.stdout with a "proxy". And pytest needs it for capture?
+    # (clue: "pytest --capture=no" avoids the error)
+    stdout = sys.stdout
+    sys.stdout._testProxy = lambda: ''
+    sys.stdout.pop = lambda _: ''
+    sys.stdout.push = lambda _: ''
+    sys.stdout.clear = lambda _: ''
+
+    try:
+        WorkflowConfig(workflow=reg, fpath=flow_file, options=Values())
+    except expected_err[0] as exc:
+        assert expected_err[1] in str(exc)
+
+    sys.stdout = stdout
+
+
 def test_valid_rsync_includes_returns_correct_list(tmp_flow_config):
     """Test that the rsync includes in the correct """
     id_ = 'rsynctest'