feat: zero downtime deployment script unlocked

docker-update.zsh

@@ -1,8 +1,36 @@
 #!/usr/bin/env zsh
-
-echo updating docker compose with latest build image
+set -e
+echo "pulling latest build image..."
 docker compose pull
-docker compose up -d
-echo finished updating and builing. Site will be down for a few seconds
+
+# Check which service is running
+if docker compose ps blog-blue --filter "status=running" -q | grep -q .; then
+	CURRENT="blog-blue"
+	TARGET="blog-green"
+else
+	CURRENT="blog-green"
+	TARGET="blog-blue"
+fi
+
+echo "Current: $CURRENT -> deploying Target: $TARGET"
+
+# TODO dont run if 0 instances running
+# Scale current deployment to two instances, keeping the old one and adding a running env of the new one
+docker compose up -d --no-deps $TARGET
+
+echo "waiting for $TARGET to pass healthcheck..."
+# docker ps --filter 'label=com.docker.compose.service=blog' --filter 'health=starting'
+until [[ "$(docker inspect --format '{{.State.Health.Status}}' $(docker compose ps -q $TARGET) 2>/dev/null)" == "healthy" ]]; do
+	sleep 1
+done
+
+# Give traefik backend a few seconds to update
+sleep 3
+
+echo "Stopping $CURRENT..."
+docker compose stop $CURRENT
+docker compose rm -f $CURRENT
+
+echo "Zero downtime deployment to $TARGET complete."
 # TODO zero downtime deployment
 # TODO run on a cron job