perf(scripts): improve load balancing

scripts/start.sh

@@ -1,14 +1,61 @@
 #!/bin/bash
+#
+# Starter script used in docker image.
+#
+# Usages are:
+#
+# 1. ./start.sh
+#    Starts antares web server with gunicorn.
+#    Number of workers is defined by GUNICORN_WORKERS env variable,
+#    or equal to 2*cpu + 1.
+#
+# 2. ./start.sh <module>
+#    Where module is for example "watcher".
+#    Starts one of the backend services (watcher, garbage collector, ...)
+#
+# 3. ./start.sh --no-gunicorn
+#    Starts multiple workers on different ports. You are expected to
+#    configure some load balancing upstream, in that case.
+#    Number of workers is defined by ANTARES_NB_WORKERS env variable,
+#    or equal to 2*cpu + 1.
 
 set -e
 
 CUR_DIR=$(cd "$(dirname "$0")" && pwd)
 BASE_DIR=$(dirname "$CUR_DIR")
 
+min() {
+    echo $(( $1 < $2 ? $1 : $2 ))
+}
+
+workers=$(min 30 ${ANTARES_NB_WORKERS:-$((2*$(nproc) + 1))}) # default (2*nproc + 1) and max is 30
+
+# Check for --no-gunicorn or --multiple-ports argument
+use_uvicorn=false
+for arg in "$@"
+do
+    if [[ $arg == "--no-gunicorn" || $arg == "--multiple-ports" ]]; then
+        use_uvicorn=true
+        break
+    fi
+done
+
 if [ -z "$1" ] ; then
   sh $CUR_DIR/pre-start.sh
   gunicorn --config $BASE_DIR/conf/gunicorn.py --worker-class=uvicorn.workers.UvicornWorker antarest.wsgi:app
+elif [ "$use_uvicorn" = true ]; then
+  sh $CUR_DIR/pre-start.sh
+  pids=() # Initialize empty array to store background process IDs
+  for ((i=0; i<workers; i++))
+  do
+    uvicorn antarest.wsgi:app --host 0.0.0.0 --port $((5000 + $i)) --log-level info --timeout-keep-alive 600 &
+    pids+=($!) # Store background process IDs
+  done
+  for pid in ${pids[*]};
+  do
+    wait $pid # Wait for each background process to finish
+  done
 else
   export PYTHONPATH=$BASE_DIR
   python3 $BASE_DIR/antarest/main.py -c $ANTAREST_CONF --module "$1"
-fi
+fi