Implement UPP output() method

docs/sections/user_guide/cli/drivers/upp/show-schema.out

@@ -3,6 +3,9 @@
     "upp": {
       "additionalProperties": false,
       "properties": {
+        "control_file": {
+          "type": "string"
+        },
         "execution": {
           "additionalProperties": false,
           "properties": {
@@ -15,6 +18,3 @@
                 "debug": {
                   "type": "boolean"
                 },
-                "exclusive": {
-                  "type": "boolean"
-                },

docs/shared/upp.yaml

@@ -1,4 +1,5 @@
 upp:
+  control_file: /path/to/postxconfig-NT.txt
   execution:
     batchargs:
       export: NONE
@@ -12,8 +13,6 @@ upp:
     mpiargs:
       - "--ntasks $SLURM_CPUS_ON_NODE"
     mpicmd: srun
-  files_to_copy:
-    postxconfig-NT.txt: /path/to/postxconfig-NT.txt
   files_to_link:
     eta_micro_lookup.dat: /path/to/nam_micro_lookup.dat
     params_grib2_tbl_new: /path/to/params_grib2_tbl_new

src/uwtools/drivers/driver.py

@@ -33,6 +33,8 @@
 from uwtools.utils.file import writable
 from uwtools.utils.processing import run_shell_cmd
 
+OutputT = dict[str, Union[str, list[str]]]
+
 # NB: Class docstrings are programmatically defined.
 
 
@@ -399,7 +401,10 @@ def show_output(self):
         Show the output to be created by this component.
         """
         yield self.taskname("expected output")
-        print(json.dumps(self.output, indent=2, sort_keys=True))
+        try:
+            print(json.dumps(self.output, indent=2, sort_keys=True))
+        except UWConfigError as e:
+            log.error(e)
         yield asset(None, lambda: True)
 
     @task
@@ -428,7 +433,7 @@ def _run_via_local_execution(self):
     # Public methods
 
     @property
-    def output(self) -> dict[str, Union[str, list[str]]]:
+    def output(self) -> OutputT:
         """
         Returns a description of the file(s) created when this component runs.
         """

src/uwtools/drivers/upp.py

@@ -2,13 +2,15 @@
 A driver for UPP.
 """
 
+from math import log10
 from pathlib import Path
 
 from iotaa import asset, task, tasks
 
 from uwtools.config.formats.nml import NMLConfig
-from uwtools.drivers.driver import DriverCycleLeadtimeBased
+from uwtools.drivers.driver import DriverCycleLeadtimeBased, OutputT
 from uwtools.drivers.support import set_driver_docstring
+from uwtools.exceptions import UWConfigError
 from uwtools.strings import STR
 from uwtools.utils.tasks import file, filecopy, symlink
 
@@ -18,8 +20,24 @@ class UPP(DriverCycleLeadtimeBased):
     A driver for UPP.
     """
 
+    # Facts specific to the supported UPP version:
+
+    GENPROCTYPE_IDX = 8
+    NFIELDS = 16
+    NPARAMS = 42
+
     # Workflow tasks
 
+    @tasks
+    def control_file(self):
+        """
+        The GRIB control file.
+        """
+        yield self.taskname("GRIB control file")
+        yield filecopy(
+            src=Path(self.config["control_file"]), dst=self.rundir / "postxconfig-NT.txt"
+        )
+
     @tasks
     def files_copied(self):
         """
@@ -66,6 +84,7 @@ def provisioned_rundir(self):
         """
         yield self.taskname("provisioned run directory")
         yield [
+            self.control_file(),
             self.files_copied(),
             self.files_linked(),
             self.namelist_file(),
@@ -81,6 +100,40 @@ def driver_name(cls) -> str:
         """
         return STR.upp
 
+    @property
+    def output(self) -> OutputT:
+        """
+        Returns a description of the file(s) created when this component runs.
+        """
+        # Derive values from the current driver config. GRIB output filename suffixes include the
+        # forecast leadtime, zero-padded to at least 2 digits (more if necessary). Avoid taking the
+        # log of zero.
+        cf = self.config["control_file"]
+        leadtime = int(self.leadtime.total_seconds() / 3600)
+        suffix = ".GrbF%0{}d".format(max(2, int(log10(leadtime or 1)) + 1)) % leadtime
+        # Read the control file into an array of lines. Get the number of blocks (one per output
+        # GRIB file) and the number of variables per block. For each block, construct a filename
+        # from the block's identifier and the suffix defined above.
+        try:
+            with open(cf, "r", encoding="utf-8") as f:
+                lines = f.read().split("\n")
+        except (FileNotFoundError, PermissionError) as e:
+            raise UWConfigError(f"Could not open UPP control file {cf}") from e
+        nblocks, lines = int(lines[0]), lines[1:]
+        nvars, lines = list(map(int, lines[:nblocks])), lines[nblocks:]
+        paths = []
+        for _ in range(nblocks):
+            identifier = lines[0]
+            paths.append(str(self.rundir / (identifier + suffix)))
+            fields, lines = lines[: self.NFIELDS], lines[self.NFIELDS :]
+            _, lines = (
+                (lines[0], lines[1:])
+                if fields[self.GENPROCTYPE_IDX] == "ens_fcst"
+                else (None, lines)
+            )
+            lines = lines[self.NPARAMS * nvars.pop() :]
+        return {"gribfiles": paths}
+
     # Private helper methods
 
     @property

src/uwtools/resources/jsonschema/upp.jsonschema

@@ -3,6 +3,9 @@
     "upp": {
       "additionalProperties": false,
       "properties": {
+        "control_file": {
+          "type": "string"
+        },
         "execution": {
           "$ref": "urn:uwtools:execution-parallel"
         },
@@ -187,6 +190,7 @@
         }
       },
       "required": [
+        "control_file",
         "execution",
         "namelist",
         "rundir"

src/uwtools/tests/drivers/test_driver.py

@@ -457,6 +457,13 @@ def test_driver_show_output(capsys, config):
     assert capsys.readouterr().out.strip() == dedent(expected).strip()
 
 
+def test_driver_show_output_fail(caplog, config):
+    with patch.object(ConcreteDriverTimeInvariant, "output", new_callable=PropertyMock) as output:
+        output.side_effect = UWConfigError("FAIL")
+        ConcreteDriverTimeInvariant(config).show_output()
+    assert "FAIL" in caplog.messages
+
+
 @mark.parametrize(
     "base_file,update_values,expected",
     [

src/uwtools/tests/drivers/test_upp.py

@@ -14,7 +14,7 @@
 
 from uwtools.drivers.driver import Driver
 from uwtools.drivers.upp import UPP
-from uwtools.exceptions import UWNotImplementedError
+from uwtools.exceptions import UWConfigError
 from uwtools.logging import log
 from uwtools.tests.support import logged, regex_logged
 
@@ -25,6 +25,7 @@
 def config(tmp_path):
     return {
         "upp": {
+            "control_file": "/path/to/postxconfig-NT.txt",
             "execution": {
                 "batchargs": {
                     "cores": 1,
@@ -90,7 +91,6 @@ def leadtime():
         "_scheduler",
         "_validate",
         "_write_runscript",
-        "output",
         "run",
         "runscript",
     ],
@@ -160,10 +160,34 @@ def test_UPP_namelist_file_missing_base_file(caplog, driverobj):
     assert regex_logged(caplog, "missing.nml: State: Not Ready (external asset)")
 
 
-def test_UPP_output(driverobj):
-    with raises(UWNotImplementedError) as e:
+def test_UPP_output(driverobj, tmp_path):
+    fields = ["?"] * (UPP.NFIELDS - 1)
+    parameters = ["?"] * UPP.NPARAMS
+    # fmt: off
+    control_data = [
+        "2",                # number of blocks
+        "1",                # number variables in 2nd block
+        "2",                # number variables in 1st block
+        "FOO",              # identifier of 1st block
+        *fields,            # fields of 1st block
+        *(parameters * 2) , # variable parameters of 1st block
+        "BAR",              # identifier of 2nd block
+        *fields,            # fields of 2nd block
+        *parameters,        # variable parameters of 2nd block
+    ]
+    # fmt: on
+    control_file = tmp_path / "postxconfig-NT.txt"
+    with open(control_file, "w", encoding="utf-8") as f:
+        print("\n".join(control_data), file=f)
+    driverobj._config["control_file"] = str(control_file)
+    expected = {"gribfiles": [str(driverobj.rundir / ("%s.GrbF24" % x)) for x in ("FOO", "BAR")]}
+    assert driverobj.output == expected
+
+
+def test_UPP_output_fail(driverobj):
+    with raises(UWConfigError) as e:
         assert driverobj.output
-    assert str(e.value) == "The output() method is not yet implemented for this driver"
+    assert str(e.value) == "Could not open UPP control file %s" % driverobj.config["control_file"]
 
 
 def test_UPP_provisioned_rundir(driverobj):

src/uwtools/tests/test_schemas.py

@@ -1952,6 +1952,7 @@ def test_schema_ungrib_rundir(ungrib_prop):
 
 def test_schema_upp():
     config = {
+        "control_file": "/path/to/postxconfig-NT.txt",
         "execution": {
             "batchargs": {
                 "cores": 1,
@@ -1977,7 +1978,7 @@ def test_schema_upp():
     # Basic correctness:
     assert not errors(config)
     # Some top-level keys are required:
-    for key in ("execution", "namelist", "rundir"):
+    for key in ("control_file", "execution", "namelist", "rundir"):
         assert f"'{key}' is a required property" in errors(with_del(config, key))
     # Other top-level keys are optional:
     assert not errors({**config, "files_to_copy": {"dst": "src"}})
@@ -1986,6 +1987,12 @@ def test_schema_upp():
     assert "Additional properties are not allowed" in errors({**config, "foo": "bar"})
 
 
+def test_schema_upp_control_file(upp_prop):
+    errors = upp_prop("control_file")
+    # A string value is required:
+    assert "is not of type 'string'" in errors(None)
+
+
 def test_schema_upp_namelist(upp_prop):
     maxpathlen = 256
     errors = upp_prop("namelist")