fix: add checks and log_targets to ops.testing (#1268)

Add checks and log_targets to ops.testing add_layer so it is possible to
test it via Harness.

Fixes #1112

ops/pebble.py

@@ -1135,6 +1135,73 @@ def __eq__(self, other: Union['CheckDict', 'Check']) -> bool:
         else:
             return NotImplemented
 
+    def _merge_exec(self, other: 'ExecDict') -> None:
+        """Merges this exec object with another exec definition.
+
+        For attributes present in both objects, the passed in exec
+        attributes take precedence.
+        """
+        if self.exec is None:
+            self.exec = {}
+        for name, value in other.items():
+            if not value:
+                continue
+            if name == 'environment':
+                current = self.exec.get(name, {})
+                current.update(value)  # type: ignore
+                self.exec[name] = current
+            else:
+                self.exec[name] = value
+
+    def _merge_http(self, other: 'HttpDict') -> None:
+        """Merges this http object with another http definition.
+
+        For attributes present in both objects, the passed in http
+        attributes take precedence.
+        """
+        if self.http is None:
+            self.http = {}
+        for name, value in other.items():
+            if not value:
+                continue
+            if name == 'headers':
+                current = self.http.get(name, {})
+                current.update(value)  # type: ignore
+                self.http[name] = current
+            else:
+                self.http[name] = value
+
+    def _merge_tcp(self, other: 'TcpDict') -> None:
+        """Merges this tcp object with another tcp definition.
+
+        For attributes present in both objects, the passed in tcp
+        attributes take precedence.
+        """
+        if self.tcp is None:
+            self.tcp = {}
+        for name, value in other.items():
+            if not value:
+                continue
+            self.tcp[name] = value
+
+    def _merge(self, other: 'Check'):
+        """Merges this check object with another check definition.
+
+        For attributes present in both objects, the passed in check
+        attributes take precedence.
+        """
+        for name, value in other.__dict__.items():
+            if not value or name == 'name':
+                continue
+            if name == 'http':
+                self._merge_http(value)
+            elif name == 'tcp':
+                self._merge_tcp(value)
+            elif name == 'exec':
+                self._merge_exec(value)
+            else:
+                setattr(self, name, value)
+
 
 class CheckLevel(enum.Enum):
     """Enum of check levels."""
@@ -1162,9 +1229,8 @@ def __init__(self, name: str, raw: Optional['LogTargetDict'] = None):
         self.location = dct.get('location', '')
         self.services: List[str] = list(dct.get('services', []))
         labels = dct.get('labels')
-        if labels is not None:
-            labels = copy.deepcopy(labels)
-        self.labels: Optional[Dict[str, str]] = labels
+        labels = copy.deepcopy(labels) if labels is not None else {}
+        self.labels: Dict[str, str] = labels
 
     def to_dict(self) -> 'LogTargetDict':
         """Convert this log target object to its dict representation."""
@@ -1189,6 +1255,22 @@ def __eq__(self, other: Union['LogTargetDict', 'LogTarget']):
         else:
             return NotImplemented
 
+    def _merge(self, other: 'LogTarget'):
+        """Merges this log target object with another log target definition.
+
+        For attributes present in both objects, the passed in log target
+        attributes take precedence.
+        """
+        for name, value in other.__dict__.items():
+            if not value or name == 'name':
+                continue
+            if name == 'labels':
+                getattr(self, name).update(value)
+            elif name == 'services':
+                getattr(self, name).extend(value)
+            else:
+                setattr(self, name, value)
+
 
 class FileType(enum.Enum):
     """Enum of file types."""

ops/testing.py

@@ -3183,6 +3183,7 @@ def add_layer(
             if not combine:
                 raise RuntimeError(f'400 Bad Request: layer "{label}" already exists')
             layer = self._layers[label]
+
             for name, service in layer_obj.services.items():
                 # 'override' is actually single quoted in the real error, but
                 # it shouldn't be, hopefully that gets cleaned up.
@@ -3200,11 +3201,48 @@ def add_layer(
                     layer.services[name] = service
                 elif service.override == 'merge':
                     if combine and name in layer.services:
-                        s = layer.services[name]
-                        s._merge(service)
+                        layer.services[name]._merge(service)
                     else:
                         layer.services[name] = service
 
+            for name, check in layer_obj.checks.items():
+                if not check.override:
+                    raise RuntimeError(
+                        f'500 Internal Server Error: layer "{label}" must define'
+                        f'"override" for check "{name}"'
+                    )
+                if check.override not in ('merge', 'replace'):
+                    raise RuntimeError(
+                        f'500 Internal Server Error: layer "{label}" has invalid '
+                        f'"override" value for check "{name}"'
+                    )
+                elif check.override == 'replace':
+                    layer.checks[name] = check
+                elif check.override == 'merge':
+                    if combine and name in layer.checks:
+                        layer.checks[name]._merge(check)
+                    else:
+                        layer.checks[name] = check
+
+            for name, log_target in layer_obj.log_targets.items():
+                if not log_target.override:
+                    raise RuntimeError(
+                        f'500 Internal Server Error: layer "{label}" must define'
+                        f'"override" for log target "{name}"'
+                    )
+                if log_target.override not in ('merge', 'replace'):
+                    raise RuntimeError(
+                        f'500 Internal Server Error: layer "{label}" has invalid '
+                        f'"override" value for log target "{name}"'
+                    )
+                elif log_target.override == 'replace':
+                    layer.log_targets[name] = log_target
+                elif log_target.override == 'merge':
+                    if combine and name in layer.log_targets:
+                        layer.log_targets[name]._merge(log_target)
+                    else:
+                        layer.log_targets[name] = log_target
+
         else:
             self._layers[label] = layer_obj
 

test/test_pebble.py

@@ -1150,7 +1150,7 @@ def _assert_empty(self, target: pebble.LogTarget, name: str):
         assert target.type == ''
         assert target.location == ''
         assert target.services == []
-        assert target.labels is None
+        assert target.labels == {}
 
     def test_name_only(self):
         target = pebble.LogTarget('tgt')