DEV: make kafka an optional runtime dependency

bluesky_queueserver/manager/start_manager.py

@@ -1,5 +1,6 @@
 import argparse
 import atexit
+import importlib
 import logging
 import os
 import re
@@ -627,6 +628,13 @@ def formatter(prog):
             "Use --zmq-info-addr instead."
         )
 
+    if settings.kafka_topic is not None or settings.kafka_server is not None:
+        if importlib.util.find_spec("bluesky-kafka") is None:
+            logger.error(
+                "Must have bluesky-kafka installed to publish documents to kafka",
+            )
+        sys.exit(1)
+
     msg_queue = Queue()
     setup_console_output_redirection(msg_queue)
 

docs/source/installation.rst

@@ -42,6 +42,10 @@ Installation Steps
 
     $ pip install bluesky-queueserver
 
+  Install from PyPI with kafka dependencies::
+
+    $ pip install bluesky-queueserver[kafka]
+
   Install from conda-forge::
 
     $ conda install bluesky-queueserver -c conda-forge

setup.py

@@ -47,7 +47,7 @@
 requirements_kafka = ["bluesky-kafka"]
 
 extras_require = {"dev": sorted(set(requirements_dev)), "kafka": requirements_kafka}
-extras_require["all"] = sort(set(sum(extras_require.values())))
+extras_require["all"] = sorted(set(sum(extras_require.values(), [])))
 
 
 setup(