feat: add --profile flag to enable simpler debug profiling

Dockerfile

@@ -27,11 +27,15 @@ RUN groupadd -g 51453 synse \
 RUN apt-get update && apt-get install -y --no-install-recommends \
     tini curl \
  && rm -rf /var/lib/apt/lists/* \
+ && mkdir -p /synse \
  && mkdir -p /etc/synse \
+ && chown -R synse:synse /synse \
  && chown -R synse:synse /etc/synse
 
 COPY --from=builder /build /usr/local
 COPY ./assets/favicon.ico /etc/synse/static/favicon.ico
 
 USER synse
+WORKDIR synse
+
 ENTRYPOINT ["/usr/bin/tini", "--", "synse_server"]

synse_server/__main__.py

@@ -16,6 +16,7 @@
 
 import argparse
 import asyncio
+import cProfile
 import os
 import sys
 
@@ -44,6 +45,10 @@ def main() -> None:
         '--version', required=False, action='store_true',
         help='print the version',
     )
+    parser.add_argument(
+        '--profile', required=False, action='store_true',
+        help='profile synse server code execution,'
+    )
     args = parser.parse_args()
 
     if args.version:
@@ -54,7 +59,35 @@ def main() -> None:
         host=args.host,
         port=args.port,
     )
-    server.run()
+
+    if args.profile:
+        print("""
+        *************************
+        Running in profiling mode
+        -------------------------
+        Synse Server was run with the --profile flag. This should only be used
+        for development/debug. It should not be used in production.
+
+        After Synse Server terminates, the profiling output will be printed out
+        to console and written to file (synse-server.profile). If running in a
+        container, it is your responsibility to copy the profile data out.
+        *************************
+        """)
+        pr = cProfile.Profile()
+        pr.enable()
+
+        try:
+            server.run()
+        except Exception as e:
+            print(f'Got exception: {e}')
+        finally:
+            pr.disable()
+
+        pr.print_stats('cumulative')
+        pr.dump_stats('synse-server.profile')
+
+    else:
+        server.run()
 
 
 if __name__ == '__main__':

synse_server/server.py

@@ -5,7 +5,9 @@
 """
 
 import asyncio
+import functools
 import os
+import signal
 import sys
 
 from structlog import get_logger
@@ -118,6 +120,15 @@ def _initialize(self) -> None:
 
     def run(self) -> None:
         """Run Synse Server."""
+
+        # Register signals for graceful termination
+        for sig in ('SIGINT', 'SIGTERM'):
+            logger.info('adding signal handler to synse loop')
+            loop.synse_loop.add_signal_handler(
+                sig=getattr(signal, sig),
+                callback=functools.partial(_handle_signal, sig, loop.synse_loop),
+            )
+
         logger.info('running synse server')
 
         # If we are configured to log the header, write it to stdout instead
@@ -202,3 +213,12 @@ def reload_config(self) -> None:
         # Load and validate the configuration values.
         config.options.parse(requires_cfg=False)
         config.options.validate()
+
+
+def _handle_signal(signame, loop):
+    """Handler function for when the Synse loop receives a registered signal.
+
+    This indicates that the server should shut down gracefully.
+    """
+    logger.info('received termination signal, stopping loop', signal=signame, loop=loop)
+    loop.stop()