site-publish: honor site.yaml excludes during S3 sync

site.yaml can now declare excludes: [paths/patterns] that are passed to
`aws s3 sync` and `aws s3 cp` as --exclude flags, so the listed objects
are neither uploaded from the build dir nor deleted from the bucket.
Escape hatch for assets managed out-of-band (e.g. large PDFs uploaded
via aws-cli) that would otherwise be wiped by --delete.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/deploy.py

@@ -2,6 +2,7 @@
 
 import json
 import os
+import shlex
 import shutil
 import tempfile
 from pathlib import Path
@@ -30,7 +31,7 @@ GARAGE_ADMIN_ENDPOINT = os.environ.get(
 CACHE_CONTROL = "public, max-age=0, must-revalidate"
 
 
-def s3_sync(site_name, site_dir):
+def s3_sync(site_name, site_dir, excludes=None):
     endpoint = os.environ.get("GARAGE_S3_ENDPOINT", DEFAULT_S3_ENDPOINT)
     html_dir = site_dir / "build" / "html"
     if not html_dir.exists():
@@ -38,6 +39,12 @@ def s3_sync(site_name, site_dir):
     env("AWS_ACCESS_KEY_ID")
     env("AWS_SECRET_ACCESS_KEY")
     os.environ.setdefault("AWS_DEFAULT_REGION", "sjc001")
+    # `excludes` are patterns (site.yaml `excludes:` list) that should never
+    # be uploaded *and* should never be deleted from the bucket — escape hatch
+    # for assets managed out-of-band (e.g. large PDFs uploaded via aws-cli).
+    exclude_flags = " ".join(f"--exclude {shlex.quote(p)}" for p in (excludes or []))
+    if excludes:
+        print(f"Excluding patterns: {excludes}")
     print(f"Syncing {html_dir} → s3://{site_name} via {endpoint}")
     # `sync --delete` handles new/changed/orphaned files. `cp --recursive`
     # then re-uploads everything to refresh metadata (cache-control,
@@ -49,13 +56,15 @@ def s3_sync(site_name, site_dir):
     run(
         f"aws --endpoint-url {endpoint} s3 sync {html_dir}/ s3://{site_name}/ "
         f"--delete --only-show-errors "
-        f"--cache-control '{CACHE_CONTROL}'"
+        f"--cache-control '{CACHE_CONTROL}' "
+        f"{exclude_flags}".rstrip()
     )
     print("Re-stamping metadata on all objects...")
     run(
         f"aws --endpoint-url {endpoint} s3 cp {html_dir}/ s3://{site_name}/ "
         f"--recursive --only-show-errors "
-        f"--cache-control '{CACHE_CONTROL}'"
+        f"--cache-control '{CACHE_CONTROL}' "
+        f"{exclude_flags}".rstrip()
     )
 
 
@@ -122,7 +131,7 @@ def render_site_manifests(site_name, action_dir, app_dir, manifests_dir, cfg):
 
 
 def deploy_static(site_name, site_dir, action_dir, token, cfg):
-    s3_sync(site_name, site_dir)
+    s3_sync(site_name, site_dir, excludes=cfg.get("excludes"))
     ensure_bucket_aliases(site_name, cfg["aliases"], os.environ.get("GARAGE_ADMIN_TOKEN"))
 
     apps_dir = clone_apps(token)