fix(upload): prevent overlapping cron runs

Dockerfile.scheduler

@@ -1,5 +1,8 @@
 FROM nginx:alpine
 
 COPY scripts/video-upload-crontab /etc/crontabs/root
+COPY scripts/process-scheduled-video-uploads.sh /usr/local/bin/process-scheduled-video-uploads
+
+RUN chmod 0755 /usr/local/bin/process-scheduled-video-uploads
 
 ENTRYPOINT ["crond", "-f", "-l", "2", "-L", "/dev/stdout"]

scripts/process-scheduled-video-uploads.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+set -eu
+
+upload_cron_lock=/tmp/erika-video-upload-cron.lock
+
+if ! mkdir "$upload_cron_lock" 2>/dev/null; then
+  echo "Previous scheduled video upload run is still active; skipping this minute."
+  exit 0
+fi
+
+trap 'rmdir "$upload_cron_lock"' EXIT INT TERM
+
+wget -q -O /dev/null \
+  --header="Authorization: Bearer ${CRON_SECRET}" \
+  http://app:3000/api/cron/video-uploads || {
+    echo "Scheduled video upload processing failed." >&2
+    exit 1
+  }

scripts/video-upload-crontab

@@ -1 +1 @@
-* * * * * wget -q -O /dev/null --header="Authorization: Bearer ${CRON_SECRET}" http://app:3000/api/cron/video-uploads || echo "Scheduled video upload processing failed." >&2
+* * * * * /usr/local/bin/process-scheduled-video-uploads