Allow demo worker count override

Makefile

@@ -1,7 +1,7 @@
 .PHONY: demo-ui demo-down demo-logs
 
 # Convenient entry points from the repository root. Extra settings are passed
-# through, for example: make demo-ui DEMO_WORKERS=3
+# through, for example: make demo-ui WORKERS=3
 demo-ui:
 	$(MAKE) -C coordinator demo-ui
 

coordinator/Makefile

@@ -19,6 +19,9 @@ DEMO_COORDINATOR_PORT ?= 18080
 DEMO_UI_TOKEN ?= demo-ui-secret
 DEMO_WORKER_TOKEN ?= demo-worker-token
 DEMO_WORKERS ?= 2
+# Short public knob for `make demo-ui WORKERS=3`; DEMO_WORKERS remains useful
+# for scripts and backwards-compatible documentation.
+WORKERS ?= $(DEMO_WORKERS)
 DEMO_DIR ?= .demo
 
 demo-ui:
@@ -27,7 +30,7 @@ demo-ui:
 	DEMO_COORDINATOR_PORT="$(DEMO_COORDINATOR_PORT)" \
 	DEMO_UI_TOKEN="$(DEMO_UI_TOKEN)" \
 	DEMO_WORKER_TOKEN="$(DEMO_WORKER_TOKEN)" \
-	DEMO_WORKERS="$(DEMO_WORKERS)" \
+	DEMO_WORKERS="$(WORKERS)" \
 	DEMO_DIR="$(DEMO_DIR)" \
 	./scripts/demo-ui.sh start
 

coordinator/README.md

@@ -106,7 +106,7 @@ This uses a separate Docker project and ports `18080` (coordinator) and
 `55432` (PostgreSQL), so it does not conflict with the normal stack. Open
 `http://localhost:18080/ui`, use username `operator` and password
 `demo-ui-secret`, upload a small ChEMBL TSV, and observe the workers process
-it. Change the worker count with `make demo-ui DEMO_WORKERS=3`; stop all demo
+it. Change the worker count with `make demo-ui WORKERS=3`; stop all demo
 services and workers with `make demo-down`.
 
 `up` starts three services in order: Postgres waits until `pg_isready` passes, a