Use task queue to spawn multiple processes of tidy

action.yml

@@ -61,6 +61,10 @@ inputs:
     description: "Use annotations instead of comments. See README for limitations on annotations"
     required: false
     default: false
+  parallel:
+    description: "Number of tidy instances to be run in parallel. Zero will automatically determine the right number."
+    required: false
+    default: "0"
   pr:
     default: ${{ github.event.pull_request.number }}
   repo:
@@ -88,3 +92,4 @@ runs:
     - --lgtm-comment-body='${{ inputs.lgtm_comment_body }}'
     - --split_workflow=${{ inputs.split_workflow }}
     - --annotations=${{ inputs.annotations }}
+    - --parallel=${{ inputs.parallel }}

post/clang_tidy_review/clang_tidy_review/__init__.py

@@ -9,7 +9,14 @@
 import glob
 import itertools
 import json
+import multiprocessing
 import os
+import queue
+import shutil
+import sys
+import tempfile
+import threading
+import traceback
 from operator import itemgetter
 import pprint
 import pathlib
@@ -160,50 +167,48 @@ def get_auth_from_arguments(args: argparse.Namespace) -> Auth:
 
 
 def build_clang_tidy_warnings(
-    line_filter,
-    build_dir,
-    clang_tidy_checks,
-    clang_tidy_binary: pathlib.Path,
-    config_file,
-    files,
-    username: str,
+    base_invocation: List,
+    env: dict,
+    tmpdir: str,
+    task_queue: queue.Queue,
+    lock: threading.Lock,
+    failed_files: List,
 ) -> None:
-    """Run clang-tidy on the given files and save output into FIXES_FILE"""
+    """Run clang-tidy on the given files and save output into a temporary file"""
 
-    config = config_file_or_checks(clang_tidy_binary, clang_tidy_checks, config_file)
+    while True:
+        name = task_queue.get()
+        invocation = base_invocation[:]
 
-    args = [
-        clang_tidy_binary,
-        f"-p={build_dir}",
-        f"-line-filter={line_filter}",
-        f"--export-fixes={FIXES_FILE}",
-        "--enable-check-profile",
-        f"-store-check-profile={PROFILE_DIR}",
-    ]
+        # Get a temporary file. We immediately close the handle so clang-tidy can
+        # overwrite it.
+        (handle, fixes_file) = tempfile.mkstemp(suffix=".yaml", dir=tmpdir)
+        os.close(handle)
+        invocation.append(f"--export-fixes={fixes_file}")
 
-    if config:
-        print(f"Using config: {config}")
-        args.append(config)
-    else:
-        print("Using recursive directory config")
+        invocation.append(name)
 
-    args += files
-
-    try:
-        with message_group(f"Running:\n\t{args}"):
-            env = dict(os.environ)
-            env["USER"] = username
-            subprocess.run(
-                args,
-                capture_output=True,
-                check=True,
-                encoding="utf-8",
-                env=env,
-            )
-    except subprocess.CalledProcessError as e:
-        print(
-            f"\n\nclang-tidy failed with return code {e.returncode} and error:\n{e.stderr}\nOutput was:\n{e.stdout}"
+        proc = subprocess.Popen(
+            invocation, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env
         )
+        output, err = proc.communicate()
+        end = datetime.datetime.now()
+
+        if proc.returncode != 0:
+            if proc.returncode < 0:
+                msg = "%s: terminated by signal %d\n" % (name, -proc.returncode)
+                err += msg.encode("utf-8")
+            failed_files.append(name)
+        with lock:
+            subprocess.list2cmdline(invocation)
+            sys.stdout.write(
+                f'{name}: {subprocess.list2cmdline(invocation)}\n{output.decode("utf-8")}'
+            )
+            if len(err) > 0:
+                sys.stdout.flush()
+                sys.stderr.write(err.decode("utf-8"))
+
+        task_queue.task_done()
 
 
 def clang_tidy_version(clang_tidy_binary: pathlib.Path):
@@ -249,11 +254,33 @@ def config_file_or_checks(
     return "--config"
 
 
-def load_clang_tidy_warnings():
-    """Read clang-tidy warnings from FIXES_FILE. Can be produced by build_clang_tidy_warnings"""
+def merge_replacement_files(tmpdir: str, mergefile: str):
+    """Merge all replacement files in a directory into a single file"""
+    # The fixes suggested by clang-tidy >= 4.0.0 are given under
+    # the top level key 'Diagnostics' in the output yaml files
+    mergekey = "Diagnostics"
+    merged = []
+    for replacefile in glob.iglob(os.path.join(tmpdir, "*.yaml")):
+        content = yaml.safe_load(open(replacefile, "r"))
+        if not content:
+            continue  # Skip empty files.
+        merged.extend(content.get(mergekey, []))
+
+    if merged:
+        # MainSourceFile: The key is required by the definition inside
+        # include/clang/Tooling/ReplacementsYaml.h, but the value
+        # is actually never used inside clang-apply-replacements,
+        # so we set it to '' here.
+        output = {"MainSourceFile": "", mergekey: merged}
+        with open(mergefile, "w") as out:
+            yaml.safe_dump(output, out)
+
+
+def load_clang_tidy_warnings(fixes_file) -> Dict:
+    """Read clang-tidy warnings from fixes_file. Can be produced by build_clang_tidy_warnings"""
     try:
-        with open(FIXES_FILE, "r") as fixes_file:
-            return yaml.safe_load(fixes_file)
+        with open(fixes_file, "r") as file:
+            return yaml.safe_load(file)
     except FileNotFoundError:
         return {}
 
@@ -820,7 +847,9 @@ def create_review_file(
     return review
 
 
-def make_timing_summary(clang_tidy_profiling: Dict, sha: Optional[str] = None) -> str:
+def make_timing_summary(
+    clang_tidy_profiling: Dict, real_time: datetime.timedelta, sha: Optional[str] = None
+) -> str:
     if not clang_tidy_profiling:
         return ""
     top_amount = 10
@@ -893,7 +922,9 @@ def make_timing_summary(clang_tidy_profiling: Dict, sha: Optional[str] = None) -
             c = decorate_check_names(f"[{c}]").replace("[[", "[").rstrip("]")
             check_summary += f"|{c}|{u:.2f}|{s:.2f}|{w:.2f}|\n"
 
-    return f"## Timing\n{file_summary}{check_summary}"
+    return (
+        f"## Timing\nReal time: {real_time.seconds:.2f}\n{file_summary}{check_summary}"
+    )
 
 
 def filter_files(diff, include: List[str], exclude: List[str]) -> List:
@@ -915,6 +946,7 @@ def create_review(
     clang_tidy_checks: str,
     clang_tidy_binary: pathlib.Path,
     config_file: str,
+    max_task: int,
     include: List[str],
     exclude: List[str],
 ) -> Optional[PRReview]:
@@ -923,6 +955,9 @@ def create_review(
 
     """
 
+    if max_task == 0:
+        max_task = multiprocessing.cpu_count()
+
     diff = pull_request.get_pr_diff()
     print(f"\nDiff from GitHub PR:\n{diff}\n")
 
@@ -962,18 +997,68 @@ def create_review(
     username = pull_request.get_pr_author() or "your name here"
 
     # Run clang-tidy with the configured parameters and produce the CLANG_TIDY_FIXES file
-    build_clang_tidy_warnings(
-        line_ranges,
-        build_dir,
-        clang_tidy_checks,
+    return_code = 0
+    export_fixes_dir = tempfile.mkdtemp()
+    env = dict(os.environ, USER=username)
+    config = config_file_or_checks(clang_tidy_binary, clang_tidy_checks, config_file)
+    base_invocation = [
         clang_tidy_binary,
-        config_file,
-        files,
-        username,
-    )
+        f"-p={build_dir}",
+        f"-line-filter={line_ranges}",
+        "--enable-check-profile",
+        f"-store-check-profile={PROFILE_DIR}",
+    ]
+    if config:
+        print(f"Using config: {config}")
+        base_invocation.append(config)
+    else:
+        print("Using recursive directory config")
+
+    print(f"Spawning a task queue with {max_task} processes")
+    start = datetime.datetime.now()
+    try:
+        # Spin up a bunch of tidy-launching threads.
+        task_queue = queue.Queue(max_task)
+        # List of files with a non-zero return code.
+        failed_files = []
+        lock = threading.Lock()
+        for _ in range(max_task):
+            t = threading.Thread(
+                target=build_clang_tidy_warnings,
+                args=(
+                    base_invocation,
+                    env,
+                    export_fixes_dir,
+                    task_queue,
+                    lock,
+                    failed_files,
+                ),
+            )
+            t.daemon = True
+            t.start()
+
+        # Fill the queue with files.
+        for name in files:
+            task_queue.put(name)
+
+        # Wait for all threads to be done.
+        task_queue.join()
+        if len(failed_files):
+            return_code = 1
+
+    except KeyboardInterrupt:
+        # This is a sad hack. Unfortunately subprocess goes
+        # bonkers with ctrl-c and we start forking merrily.
+        print("\nCtrl-C detected, goodbye.")
+        os.kill(0, 9)
+        raise
+    real_duration = datetime.datetime.now() - start
 
     # Read and parse the CLANG_TIDY_FIXES file
-    clang_tidy_warnings = load_clang_tidy_warnings()
+    print("Writing fixes to " + FIXES_FILE + " ...")
+    merge_replacement_files(export_fixes_dir, FIXES_FILE)
+    shutil.rmtree(export_fixes_dir)
+    clang_tidy_warnings = load_clang_tidy_warnings(FIXES_FILE)
 
     # Read and parse the timing data
     clang_tidy_profiling = load_and_merge_profiling()
@@ -985,7 +1070,7 @@ def create_review(
 
     # Post to the action job summary
     step_summary = ""
-    step_summary += make_timing_summary(clang_tidy_profiling, sha)
+    step_summary += make_timing_summary(clang_tidy_profiling, real_duration, sha)
     set_summary(step_summary)
 
     print("clang-tidy had the following warnings:\n", clang_tidy_warnings, flush=True)

post/clang_tidy_review/clang_tidy_review/review.py

@@ -112,6 +112,13 @@ def main():
         type=bool_argument,
         default=False,
     )
+    parser.add_argument(
+        "-j",
+        "--parallel",
+        help="Number of tidy instances to be run in parallel.",
+        type=int,
+        default=0,
+    )
     parser.add_argument(
         "--dry-run", help="Run and generate review, but don't post", action="store_true"
     )
@@ -157,6 +164,7 @@ def main():
         args.clang_tidy_checks,
         args.clang_tidy_binary,
         args.config_file,
+        args.parallel,
         include,
         exclude,
     )

tests/test_review.py

@@ -1,3 +1,5 @@
+import datetime
+
 import clang_tidy_review as ctr
 
 import difflib
@@ -235,10 +237,10 @@ def test_line_ranges():
     assert line_ranges == expected_line_ranges
 
 
-def test_load_clang_tidy_warnings(monkeypatch):
-    monkeypatch.setattr(ctr, "FIXES_FILE", str(TEST_DIR / f"src/test_{ctr.FIXES_FILE}"))
-
-    warnings = ctr.load_clang_tidy_warnings()
+def test_load_clang_tidy_warnings():
+    warnings = ctr.load_clang_tidy_warnings(
+        str(TEST_DIR / f"src/test_{ctr.FIXES_FILE}")
+    )
 
     assert sorted(list(warnings.keys())) == ["Diagnostics", "MainSourceFile"]
     assert warnings["MainSourceFile"] == "/clang_tidy_review/src/hello.cxx"
@@ -470,5 +472,5 @@ def test_timing_summary(monkeypatch):
     assert "time.clang-tidy.total.wall" in profiling["hello.cxx"].keys()
     assert "time.clang-tidy.total.user" in profiling["hello.cxx"].keys()
     assert "time.clang-tidy.total.sys" in profiling["hello.cxx"].keys()
-    summary = ctr.make_timing_summary(profiling)
-    assert len(summary.split("\n")) == 21
+    summary = ctr.make_timing_summary(profiling, datetime.timedelta(seconds=42))
+    assert len(summary.split("\n")) == 22