Configurable worker count. Closes #1668.

docker-compose.yml

@@ -34,6 +34,7 @@ services:
       - WO_DEV
       - WO_DEV_WATCH_PLUGINS
       - WO_SECRET_KEY
+      - WEB_CONCURRENCY
     restart: unless-stopped
     oom_score_adj: 0
   broker:

start.sh

@@ -144,6 +144,18 @@ else
         conf="nginx-ssl.conf"
     fi
 
+    # Only set if `WEB_CONCURRENCY` is not defined, allows overriding.
+    # See: https://docs.gunicorn.org/en/latest/settings.html#workers
+    if [ -z "$WEB_CONCURRENCY" ]; then
+        # Default gunicorn worker count to 2 x availabe cores + 1
+        # nproc gives _available_ (rather than physicall present) CPU cores.
+        CPU_COUNT=$(nproc)
+        export WEB_CONCURRENCY=$((2*$CPU_COUNT+1))
+        echo "Setting WEB_CONCURRENCY based on $CPU_COUNT available CPU cores to start $WEB_CONCURRENCY gunicorn workers."
+    else
+        echo "Using pre-defined WEB_CONCURRENCY override to start $WEB_CONCURRENCY gunicorn workers."
+    fi
+
     congrats
 
     nginx -c $(pwd)/nginx/$conf