Default to Uvicorn workers=1, refs #999

datasette/cli.py

@@ -465,7 +465,9 @@ def serve(
         url = "http://{}:{}/".format(host, port)
     if open_browser:
         webbrowser.open(url)
-    uvicorn.run(ds.app(), host=host, port=port, log_level="info", lifespan="on")
+    uvicorn.run(
+        ds.app(), host=host, port=port, log_level="info", lifespan="on", workers=1
+    )
 
 
 async def check_databases(ds):

datasette/publish/heroku.py

@@ -73,10 +73,7 @@ def publish_subcommand(publish):
             "about_url": about_url,
         }
 
-        environment_variables = {
-            # Avoid uvicorn error: https://github.com/simonw/datasette/issues/633
-            "WEB_CONCURRENCY": "1"
-        }
+        environment_variables = {}
         if plugin_secret:
             extra_metadata["plugins"] = {}
             for plugin_name, plugin_setting, setting_value in plugin_secret: