1 files changed, 115 insertions, 0 deletions
diff --git a/src/ansiblelint/rules/complexity.py b/src/ansiblelint/rules/complexity.py
new file mode 100644
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+++ b/src/ansiblelint/rules/complexity.py
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+"""Implementation of limiting number of tasks."""
+
+from __future__ import annotations
+
+import re
+import sys
+from typing import TYPE_CHECKING, Any
+
+from ansiblelint.constants import LINE_NUMBER_KEY
+from ansiblelint.rules import AnsibleLintRule, RulesCollection
+
+if TYPE_CHECKING:
+    from ansiblelint.config import Options
+    from ansiblelint.errors import MatchError
+    from ansiblelint.file_utils import Lintable
+    from ansiblelint.utils import Task
+
+
+class ComplexityRule(AnsibleLintRule):
+    """Rule for limiting number of tasks inside a file."""
+
+    id = "complexity"
+    description = "There should be limited tasks executed inside any file"
+    severity = "MEDIUM"
+    tags = ["experimental", "idiom"]
+    version_added = "v6.18.0 (last update)"
+    _re_templated_inside = re.compile(r".*\{\{.*\}\}.*\w.*$")
+
+    def matchplay(self, file: Lintable, data: dict[str, Any]) -> list[MatchError]:
+        """Call matchplay for up to no_of_max_tasks inside file and return aggregate results."""
+        results: list[MatchError] = []
+
+        if file.kind != "playbook":
+            return []
+        tasks = data.get("tasks", [])
+        if not isinstance(self._collection, RulesCollection):
+            msg = "Rules cannot be run outside a rule collection."
+            raise TypeError(msg)
+        if len(tasks) > self._collection.options.max_tasks:
+            results.append(
+                self.create_matcherror(
+                    message=f"Maximum tasks allowed in a play is {self._collection.options.max_tasks}.",
+                    lineno=data[LINE_NUMBER_KEY],
+                    tag=f"{self.id}[play]",
+                    filename=file,
+                ),
+            )
+        return results
+
+    def matchtask(self, task: Task, file: Lintable | None = None) -> list[MatchError]:
+        """Check if the task is a block and count the number of items inside it."""
+        results: list[MatchError] = []
+
+        if not isinstance(self._collection, RulesCollection):
+            msg = "Rules cannot be run outside a rule collection."
+            raise TypeError(msg)
+
+        if task.action == "block/always/rescue":
+            block_depth = self.calculate_block_depth(task)
+            if block_depth > self._collection.options.max_block_depth:
+                results.append(
+                    self.create_matcherror(
+                        message=f"Replace nested block with an include_tasks to make code easier to maintain. Maximum block depth allowed is {self._collection.options.max_block_depth}.",
+                        lineno=task[LINE_NUMBER_KEY],
+                        tag=f"{self.id}[nesting]",
+                        filename=file,
+                    ),
+                )
+        return results
+
+    def calculate_block_depth(self, task: Task) -> int:
+        """Recursively calculate the block depth of a task."""
+        if not isinstance(task.position, str):
+            raise NotImplementedError
+        return task.position.count(".block")
+
+
+if "pytest" in sys.modules:
+    import pytest
+
+    # pylint: disable=ungrouped-imports
+    from ansiblelint.runner import Runner
+
+    @pytest.mark.parametrize(
+        ("file", "expected_results"),
+        (
+            pytest.param(
+                "examples/playbooks/rule-complexity-pass.yml",
+                [],
+                id="pass",
+            ),
+            pytest.param(
+                "examples/playbooks/rule-complexity-fail.yml",
+                ["complexity[play]", "complexity[nesting]"],
+                id="fail",
+            ),
+        ),
+    )
+    def test_complexity(
+        file: str,
+        expected_results: list[str],
+        monkeypatch: pytest.MonkeyPatch,
+        config_options: Options,
+    ) -> None:
+        """Test rule."""
+        monkeypatch.setattr(config_options, "max_tasks", 5)
+        monkeypatch.setattr(config_options, "max_block_depth", 3)
+        collection = RulesCollection(options=config_options)
+        collection.register(ComplexityRule())
+        results = Runner(file, rules=collection).run()
+
+        assert len(results) == len(expected_results)
+        for i, result in enumerate(results):
+            assert result.rule.id == ComplexityRule.id, result
+            assert result.tag == expected_results[i]