Stabilize Bicep validation by restoring artifacts before parallel builds

.github/scripts/validate_bicep.py

@@ -1,6 +1,8 @@
+import concurrent.futures
 import os
+from pathlib import Path
+import re
 import subprocess
-import concurrent.futures
 
 num_workers = 5
 
@@ -30,12 +32,60 @@
 failures = []
 warnings = []
 
+extension_pattern = re.compile(r'^\s*extension\s+([A-Za-z0-9_-]+)\s*$', re.MULTILINE)
+registry_reference_pattern = re.compile(r'br:[^\s\'"]+')
+repo_root = Path(".").resolve()
+
 # Walk the directory tree and find all .bicep files
 for root, _, filenames in os.walk("."):
     for filename in filenames:
         if filename.endswith(".bicep"):
             files.append(os.path.join(root, filename))
 
+
+def find_bicep_config_path(file_path):
+    current_path = Path(file_path).resolve().parent
+
+    while True:
+        config_path = current_path / "bicepconfig.json"
+        if config_path.exists():
+            return str(config_path.relative_to(repo_root))
+
+        if current_path == repo_root:
+            return None
+
+        current_path = current_path.parent
+
+
+def requires_restore(file_path):
+    file_contents = Path(file_path).read_text(encoding="utf-8")
+    extensions = tuple(sorted(set(extension_pattern.findall(file_contents))))
+    registry_references = tuple(sorted(set(registry_reference_pattern.findall(file_contents))))
+
+    if not extensions and not registry_references:
+        return None
+
+    return (find_bicep_config_path(file_path), extensions, registry_references)
+
+
+def restore_file(f):
+    print(f"Restoring artifacts for {f}...", flush=True)
+
+    result = subprocess.run(
+        [bicep_executable, "restore", f],
+        stderr=subprocess.PIPE,
+        stdout=subprocess.DEVNULL,
+    )
+    stderr = result.stderr.decode("utf-8")
+    exitcode = result.returncode
+
+    if exitcode != 0 or "Error" in stderr:
+        failures.append(f)
+        print(stderr, flush=True)
+        return False
+
+    return True
+
 def validate_file(f):
     print(f"Validating {f}...", flush=True)
 
@@ -55,8 +105,21 @@ def validate_file(f):
         failures.append(f)
         print(stderr, flush=True)
 
+
+files_to_skip = set()
+restore_targets = {}
+
+for file_path in files:
+    restore_key = requires_restore(file_path)
+    if restore_key:
+        restore_targets.setdefault(restore_key, []).append(file_path)
+
+for restore_group in restore_targets.values():
+    if not restore_file(restore_group[0]):
+        files_to_skip.update(restore_group)
+
 with concurrent.futures.ThreadPoolExecutor(max_workers=num_workers) as executor:
-    futures = [executor.submit(validate_file, f) for f in files]
+    futures = [executor.submit(validate_file, f) for f in files if f not in files_to_skip]
 concurrent.futures.wait(futures)
 
 for f in failures: