[feature] Run collectstatic only when python dependencies change #246

.env

@@ -60,3 +60,5 @@ USE_OPENWISP_CELERY_FIRMWARE=True
 OPENWISP_CELERY_FIRMWARE_COMMAND_FLAGS=--concurrency=1
 # Metric collection
 METRIC_COLLECTION=True
+# collectstatic
+COLLECTSTATIC_WHEN_DEPS_CHANGE=true

docs/user/settings.rst

@@ -1164,3 +1164,12 @@ NFS Server
 - **Valid Values:** STRING.
 - **Default:**
   ``10.0.0.0/8(rw,fsid=0,insecure,no_root_squash,no_subtree_check,sync)``.
+
+``COLLECTSTATIC_WHEN_DEPS_CHANGE``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- **Description:** Runs ``collectstatic`` at container startup only if
+  Python dependencies have changed. Set to ``false`` if you're using the
+  development version of the OpenWISP python modules.
+- **Accepted Values:** ``true``, ``false``
+- **Default:** ``true``

images/common/collectstatic.py

@@ -0,0 +1,51 @@
+"""Run ``collectstatic`` only when dependencies have changed.
+
+Speeds up startup time on cloud platforms. To disable this behavior, set
+the ``COLLECTSTATIC_WHEN_DEPS_CHANGE`` environment variable to ``False``.
+"""
+
+import hashlib
+import os
+import subprocess
+import sys
+
+import django
+import redis
+from django.conf import settings
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "openwisp.settings")
+django.setup()
+
+
+def get_pip_freeze_hash():
+    try:
+        pip_freeze_output = subprocess.check_output(["pip", "freeze"]).decode()
+        return hashlib.sha256(pip_freeze_output.encode()).hexdigest()
+    except subprocess.CalledProcessError as e:
+        print(f"Error running 'pip freeze': {e}", file=sys.stderr)
+        sys.exit(1)
+
+
+def run_collectstatic():
+    try:
+        subprocess.run(
+            ["python", "manage.py", "collectstatic", "--noinput"], check=True
+        )
+    except subprocess.CalledProcessError as e:
+        print(f"Error running 'collectstatic': {e}", file=sys.stderr)
+        sys.exit(1)
+
+
+def main():
+    if os.environ.get("COLLECTSTATIC_WHEN_DEPS_CHANGE", "true").lower() == "false":
+        run_collectstatic()
+        return
+    redis_connection = redis.Redis.from_url(settings.CACHES["default"]["LOCATION"])
+    current_pip_hash = get_pip_freeze_hash()
+    cached_pip_hash = redis_connection.get("pip_freeze_hash")
+    if cached_pip_hash is None or cached_pip_hash.decode() != current_pip_hash:
+        print("Changes in Python dependencies detected, running collectstatic...")
+        run_collectstatic()
+        redis_connection.set("pip_freeze_hash", current_pip_hash)
+    else:
+        print("No changes in Python dependencies, skipping collectstatic...")

images/common/init_command.sh

@@ -14,7 +14,7 @@ if [ "$MODULE_NAME" = 'dashboard' ]; then
 	python manage.py migrate --noinput
 	test -f "$SSH_PRIVATE_KEY_PATH" || ssh-keygen -t ed25519 -f "$SSH_PRIVATE_KEY_PATH" -N ""
 	python load_init_data.py
-	python manage.py collectstatic --noinput
+	python collectstatic.py
 	start_uwsgi
 elif [ "$MODULE_NAME" = 'postfix' ]; then
 	postfix_config