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Style

These are all the checkers used by our style enforcement.

ruff

An extremely fast Python linter and formatter that subsumes the roles previously played by black, isort, flake8, and several flake8 plugins. The repo's centralized configuration lives under [tool.ruff] in the root pyproject.toml; per-integration hatch lint envs install a pinned ruff version.

Formatting

ruff format is the formatter (a drop-in for black). Quote style is set to preserve so existing single-quoted strings are kept as-is. Run via ddev test -fs <integration>.

Linting

ruff check enforces the rule sets selected in [tool.ruff.lint]:

  • E, W — pycodestyle errors and warnings
  • F — pyflakes
  • B — flake8-bugbear (likely bugs and design problems)
  • C — mccabe complexity
  • G — flake8-logging-format (consistent logging format)
  • I — isort (datadog_checks is configured as a first-party namespace)
  • TID252 — flake8-tidy-imports (no relative imports of parent modules)

Run via ddev test -ls <integration>. Use --fix to auto-apply fixes where ruff can.

Mypy

A comment-based type checker allowing a mix of dynamic and static typing. This is optional for now. In order to enable mypy for a specific integration, open its hatch.toml file and add the lines in the correct section:

[env.collectors.datadog-checks]
check-types: true
mypy-args = [
    "--install-types",
    "--non-interactive",
]
mypy-files = [
    "datadog_checks/",
    "tests/",
]
mypy-deps = [
  "types-mock==0.1.5",
]
...

The mypy-args defines the mypy command line option for this specific integration. Here are some useful flags you can add:

  • --check-untyped-defs: Type-checks the interior of functions without type annotations.
  • --disallow-untyped-defs: Disallows defining functions without type annotations or with incomplete type annotations.

The datadog_checks/ tests/ arguments in mypy-files represent the list of files that mypy should type check. Feel free to edit them as desired, including removing tests/ (if you'd prefer to not type-check the test suite), or targeting specific files (when doing partial type checking). If no files are listed, mypy will type-check the entire integration.

Note that the default configuration lives in the root pyproject.toml file of the integrations-core repository.

Example

Extracted from rethinkdb:

from typing import Any, Iterator # Contains the different types used

import rethinkdb

from .document_db.types import Metric

class RethinkDBCheck(AgentCheck):
    def __init__(self, *args, **kwargs):
        # type: (*Any, **Any) -> None
        super(RethinkDBCheck, self).__init__(*args, **kwargs)

    def collect_metrics(self, conn):
        # type: (rethinkdb.net.Connection) -> Iterator[Metric]
        """
        Collect metrics from the RethinkDB cluster we are connected to.
        """
        for query in self.queries:
            for metric in query.run(logger=self.log, conn=conn, config=self._config):
                yield metric

Take a look at vsphere or ibm_mq integrations for more examples.