chore(ci): single ruff pin via requirements-dev.txt

- Add requirements-dev.txt as the only ruff version pin
- CI and scripts reference it; local pre-commit hook runs scripts/lint
- Document Python lint setup in README

Author: vlad-scherbich

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
         with:
           python-version: "3.11"
       - name: Install ruff
-        run: pip install --no-cache-dir ruff==0.15.5
+        run: pip install --no-cache-dir -r requirements-dev.txt
       - name: Run ruff format check
         run: ruff format --check .
       - name: Run ruff lint check

.pre-commit-config.yaml

@@ -1,10 +1,11 @@
-# Lightweight Python formatting/lint for scenario workloads. Matches the ruff job in ci.yml.
-# Local: ./scripts/lint (check) or ./scripts/format (auto-fix)
-# Optional hooks (skipped when core.hooksPath is set): pip install pre-commit && pre-commit install
+# Optional git hooks for Python scenario files (same checks as CI — see scripts/lint).
+# Setup: pip install -r requirements-dev.txt pre-commit && pre-commit install
+# On Datadog laptops with global core.hooksPath, use ./scripts/lint instead of pre-commit install.
 repos:
-  - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.15.5
+  - repo: local
     hooks:
       - id: ruff
-        args: [--fix]
-      - id: ruff-format
+        name: ruff (scripts/lint)
+        entry: scripts/lint
+        language: system
+        types: [python]

README.md

@@ -10,6 +10,28 @@ Checkout #profiling-library-pager to get notified of test failures.
 Install go >= 1.25.1: `brew install go`, `choco install go`, etc.
 Install docker.
 
+### Python lint (scenario workloads)
+
+CI and local checks use [Ruff](https://docs.astral.sh/ruff/). Install once:
+
+```sh
+pip install -r requirements-dev.txt
+```
+
+```sh
+./scripts/lint          # check (matches the ci.yml ruff job)
+./scripts/format        # auto-fix formatting and lint
+```
+
+Optional git hooks (skip on Datadog laptops that use global `core.hooksPath` — run `./scripts/lint` manually instead):
+
+```sh
+pip install pre-commit
+pre-commit install
+```
+
+Ruff version is pinned only in `requirements-dev.txt`.
+
 ### Running Tests
 
 ```sh

requirements-dev.txt

@@ -0,0 +1,2 @@
+# Python dev tools for repo-wide lint/format (ci.yml, scripts/lint, scripts/format, pre-commit).
+ruff==0.15.5

scripts/format

@@ -3,9 +3,10 @@ set -euo pipefail
 
 root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 cd "$root"
+dev_requirements="$root/requirements-dev.txt"
 
 if ! command -v ruff >/dev/null 2>&1; then
-  echo "ruff not found; install with: pip install ruff==0.15.5" >&2
+  echo "ruff not found; install with: pip install -r $dev_requirements" >&2
   exit 1
 fi
 

scripts/lint

@@ -4,9 +4,10 @@ set -euo pipefail
 # Matches the ruff job in .github/workflows/ci.yml (see also scripts/format).
 root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 cd "$root"
+dev_requirements="$root/requirements-dev.txt"
 
 if ! command -v ruff >/dev/null 2>&1; then
-  echo "ruff not found; install with: pip install ruff==0.15.5" >&2
+  echo "ruff not found; install with: pip install -r $dev_requirements" >&2
   exit 1
 fi