complete Justfile changes

Justfile

@@ -176,19 +176,25 @@ debug *args:
   wait "$dlv_pid"
 
 # Run otel collector in a docker container to stream local (i.e. from ftl dev) signals to
-# the terminal tab where this is running. To stop the stream, run `just otel-stop` in a
-# second terminal window.
+# the terminal tab where this is running. To start FTL, opepn another terminal tab and run
+# `just otel-dev` with any args you would pass to `ftl dev`. To stop the otel stream, run
+# `just otel-stop` in a third terminal tab.
+grpcPort := `cat docker-compose.yml | grep "OTLP gRPC" | sed 's/:.*//' | sed -r 's/ +- //'`
 otel-stream:
   docker run \
-    -p 4317:4317 \
+    -p {{grpcPort}}:{{grpcPort}} \
     -p 55679:55679 \
     otel/opentelemetry-collector:0.104.0
 
+# Stop the docker container running otel.
 otelContainerID := `docker ps -f ancestor=otel/opentelemetry-collector:0.104.0 | tail -1 | cut -d " " -f1`
 otel-stop:
   docker stop "{{otelContainerID}}"
 
-# Run `ftl dev` with the given args after setting the necessary envar
+# Run `ftl dev` with the given args after setting the necessary envar.
 otel-dev *args:
-  export OTEL_EXPORTER_OTLP_ENDPOINT=localhost:4317
+  #!/bin/bash
+
+  gprcPort=$(cat docker-compose.yml | grep "OTLP gRPC" | sed 's/:.*//' | sed -r 's/ +- //')
+  export OTEL_EXPORTER_OTLP_ENDPOINT="localhost:${gprcPort}"
   ftl dev {{args}}