Add last_exposure_no to status reply (#50)

* Add last_exposure_no to status reply

* Add specific test for when data was not fetched

* Update changelog

CHANGELOG.md

@@ -6,6 +6,10 @@
 
 * Dropped support for Python 3.9.
 
+### 🚀 New
+
+* [#50](https://github.com/sdss/archon/pull/50) Added `last_exposure_no` to the output of the `status` command.
+
 ### ⚙️ Engineering
 
 * Lint and format using `ruff`.

archon/actor/commands/status.py

@@ -48,6 +48,7 @@ async def status(
                 "controller": controller.name,
                 "status": controller.status.value,
                 "status_names": [flag.name for flag in controller.status.get_flags()],
+                "last_exposure_no": command.actor.exposure_delegate.last_exposure_no,
             }
         )
         return True
@@ -57,6 +58,7 @@ async def status(
             "controller": controller.name,
             "status": controller.status.value,
             "status_names": [flag.name for flag in controller.status.get_flags()],
+            "last_exposure_no": command.actor.exposure_delegate.last_exposure_no,
             **status,
         }
     )

archon/actor/delegate.py

@@ -97,6 +97,8 @@ def __init__(self, actor: Actor_co):
 
         self.expose_data: ExposeData | None = None
 
+        self.last_exposure_no: int = -1
+
         self.use_shutter: bool = True
         self.is_writing: bool = False
 
@@ -350,6 +352,10 @@ async def readout(
         except Exception as err:
             return self.fail(f"Failed reading out: {err}")
 
+        if len(c_fdata) == 0:
+            self.command.error("No data was fetched.")
+            return False
+
         self.command.debug(f"Readout completed in {time()-t0:.1f} seconds.")
 
         if write is False:
@@ -389,6 +395,8 @@ async def readout(
             for fd in fdata
         ]
 
+        self.last_exposure_no = fdata[0]["exposure_no"]
+
         # Prepare checksum information.
         write_checksum: bool = self.config["checksum.write"]
         checksum_mode: str = self.config.get("checksum.mode", "md5")

archon/etc/schema.json

@@ -38,7 +38,8 @@
       "properties": {
         "controller": { "type": "string" },
         "status": { "type": "integer" },
-        "status_names": { "type": "array", "items": { "type": "string" } }
+        "status_names": { "type": "array", "items": { "type": "string" } },
+        "last_exposure_no": { "type": "integer" }
       },
       "additionalProperties": true,
       "required": ["controller", "status", "status_names"]

tests/actor/test_command_expose.py

@@ -272,6 +272,12 @@ async def test_expose_set_window(delegate, actor: ArchonActor):
     hdu = fits.open(filename)
     assert hdu[0].data.shape == (200, 200)  # type: ignore
 
+    command_status = await actor.invoke_mock_command("status -s")
+    await command_status
+
+    assert command_status.status.did_succeed
+    assert command_status.replies[-2].body["status"]["last_exposure_no"] != -1
+
 
 async def test_expose_with_dark(delegate, actor: ArchonActor, mocker):
     expose_mock = mocker.patch.object(delegate, "expose", return_value=True)

tests/actor/test_command_status.py

@@ -17,6 +17,9 @@ async def test_status(actor: ArchonActor):
     assert command.status.did_succeed
     assert len(command.replies) == 3
 
+    assert "last_exposure_no" in command.replies[1].body["status"]
+    assert command.replies[1].body["status"]["last_exposure_no"] == -1
+
 
 async def test_status_fail_controller(actor: ArchonActor):
     await actor.controllers["sp1"].stop()

tests/actor/test_delegate.py

@@ -264,6 +264,25 @@ async def test_delegate_shutter_fails(delegate: ExposureDelegate, mocker):
     assert result is False
 
 
+async def test_delegate_readout_no_fetch_data(delegate: ExposureDelegate):
+    command = Command("", actor=delegate.actor)
+    result = await delegate.expose(
+        command,
+        [delegate.actor.controllers["sp1"]],
+        flavour="object",
+        exposure_time=0.01,
+        readout=False,
+    )
+    assert result is True
+
+    assert delegate.expose_data
+    delegate.expose_data.controllers = []
+
+    result = await delegate.readout(command)
+    assert result is False
+    assert delegate.command.replies[-1].body["error"] == "No data was fetched."
+
+
 @pytest.mark.parametrize("window_mode", ["test_mode", "default"])
 async def test_delegate_expose_window_mode(delegate: ExposureDelegate, window_mode):
     command = Command("", actor=delegate.actor)