Attempt to reduce pop-up "flicker" (1403)

api/remote_ispyb_connector.py

@@ -11,9 +11,21 @@
     ISPyBNoResultException,
     ISPyBRetrieveFailed,
 )
+from pymysql.err import OperationalError
 
 logger: logging.Logger = logging.getLogger(__name__)
 
+# Timeout to allow the pymysql.connect() method to connect to the DB.
+# The default, if not specified, is 10 seconds.
+PYMYSQL_CONNECT_TIMEOUT_S = 3
+PYMYSQL_READ_TIMEOUT_S = 3
+PYMYSQL_WRITE_TIMEOUT_S = 10
+# MySQL DB connection attempts.
+# An attempt to cope with intermittent OperationalError exceptions
+# that are seen to occur at "busy times". See m2ms-1403.
+PYMYSQL_OE_RECONNECT_ATTEMPTS = 5
+PYMYSQL_EXCEPTION_RECONNECT_DELAY_S = 1
+
 
 class SSHConnector(Connector):
     def __init__(
@@ -53,6 +65,7 @@ def __init__(
                 'db_pass': pw,
                 'db_name': db,
             }
+            logger.debug("Creating remote connector: %s", creds)
             self.remote_connect(**creds)
             logger.debug(
                 "Started remote ssh_host=%s ssh_user=%s local_bind_port=%s",
@@ -61,6 +74,7 @@ def __init__(
                 self.server.local_bind_port,
             )
         else:
+            logger.debug("Creating connector")
             self.connect(
                 user=user,
                 pw=pw,
@@ -83,9 +97,9 @@ def remote_connect(
         db_pass,
         db_name,
     ):
-        sshtunnel.SSH_TIMEOUT = 10.0
-        sshtunnel.TUNNEL_TIMEOUT = 10.0
-        sshtunnel.DEFAULT_LOGLEVEL = logging.CRITICAL
+        sshtunnel.SSH_TIMEOUT = 5.0
+        sshtunnel.TUNNEL_TIMEOUT = 5.0
+        sshtunnel.DEFAULT_LOGLEVEL = logging.ERROR
         self.conn_inactivity = int(self.conn_inactivity)
 
         if ssh_pkey:
@@ -122,20 +136,55 @@ def remote_connect(
         self.server.start()
         logger.debug('Started SSH server')
 
-        logger.debug('Connecting to ISPyB (db_user=%s db_name=%s)...', db_user, db_name)
-        self.conn = pymysql.connect(
-            user=db_user,
-            password=db_pass,
-            host='127.0.0.1',
-            port=self.server.local_bind_port,
-            database=db_name,
-        )
+        # Try to connect to the database
+        # a number of times (because it is known to fail)
+        # before giving up...
+        connect_attempts = 0
+        self.conn = None
+        while self.conn is None and connect_attempts < PYMYSQL_OE_RECONNECT_ATTEMPTS:
+            try:
+                self.conn = pymysql.connect(
+                    user=db_user,
+                    password=db_pass,
+                    host='127.0.0.1',
+                    port=self.server.local_bind_port,
+                    database=db_name,
+                    connect_timeout=PYMYSQL_CONNECT_TIMEOUT_S,
+                    read_timeout=PYMYSQL_READ_TIMEOUT_S,
+                    write_timeout=PYMYSQL_WRITE_TIMEOUT_S,
+                )
+            except OperationalError as oe_e:
+                if connect_attempts == 0:
+                    # So we only log our connection attempts once
+                    # an error has occurred - to avoid flooding the log
+                    logger.info(
+                        'Connecting to MySQL database (db_user=%s db_name=%s)...',
+                        db_user,
+                        db_name,
+                    )
+                logger.warning('%s', repr(oe_e))
+                connect_attempts += 1
+                time.sleep(PYMYSQL_EXCEPTION_RECONNECT_DELAY_S)
+            except Exception as e:
+                if connect_attempts == 0:
+                    # So we only log our connection attempts once
+                    # an error has occurred - to avoid flooding the log
+                    logger.info(
+                        'Connecting to MySQL database (db_user=%s db_name=%s)...',
+                        db_user,
+                        db_name,
+                    )
+                logger.warning('Unexpected %s', repr(e))
+                connect_attempts += 1
+                time.sleep(PYMYSQL_EXCEPTION_RECONNECT_DELAY_S)
 
         if self.conn is not None:
-            logger.debug('Connected')
+            if connect_attempts > 0:
+                logger.info('Connected')
             self.conn.autocommit = True
         else:
-            logger.debug('Failed to connect')
+            if connect_attempts > 0:
+                logger.info('Failed to connect')
             self.server.stop()
             raise ISPyBConnectionException
         self.last_activity_ts = time.time()

api/security.py

@@ -72,19 +72,22 @@ def get_remote_conn(force_error_display=False) -> Optional[SSHConnector]:
     #          If a host is not defined other properties are useless.
     if not credentials["host"]:
         if logging.DEBUG >= logger.level or force_error_display:
-            logger.info("No ISPyB host - cannot return a connector")
+            logger.debug("No ISPyB host - cannot return a connector")
         return None
 
     # Try to get an SSH connection (aware that it might fail)
+    logger.debug("Creating remote connector with credentials: %s", credentials)
     conn: Optional[SSHConnector] = None
     try:
         conn = SSHConnector(**credentials)
     except Exception:
-        # Log the exception if DEBUG level or lower/finer?
-        # The following will not log if the level is set to INFO for example.
         if logging.DEBUG >= logger.level or force_error_display:
             logger.info("credentials=%s", credentials)
-            logger.exception("Got the following exception creating SSHConnector...")
+            logger.exception("Got the following exception creating Connector...")
+    if conn:
+        logger.debug("Got remote connector")
+    else:
+        logger.debug("Failed to get a remote connector")
 
     return conn
 
@@ -106,6 +109,7 @@ def get_conn(force_error_display=False) -> Optional[Connector]:
             logger.info("No ISPyB host - cannot return a connector")
         return None
 
+    logger.info("Creating connector with credentials: %s", credentials)
     conn: Optional[Connector] = None
     try:
         conn = Connector(**credentials)
@@ -115,6 +119,10 @@ def get_conn(force_error_display=False) -> Optional[Connector]:
         if logging.DEBUG >= logger.level or force_error_display:
             logger.info("credentials=%s", credentials)
             logger.exception("Got the following exception creating Connector...")
+    if conn:
+        logger.debug("Got connector")
+    else:
+        logger.debug("Did not get a connector")
 
     return conn
 

viewer/services.py

@@ -15,14 +15,18 @@
 
 logger = logging.getLogger(__name__)
 
-DELAY = 10
+# Service query timeout
+SERVICE_QUERY_TIMEOUT_S = 28
 # Default timeout for any request calls
+# Used for keycloak atm.
 REQUEST_TIMEOUT_S = 5
 
 _NEO4J_LOCATION: str = settings.NEO4J_QUERY
 _NEO4J_AUTH: str = settings.NEO4J_AUTH
 
 
+# TIMEOUT is no longer used.
+# A service timeout is considered a service that is degraded
 class State(str, Enum):
     NOT_CONFIGURED = "NOT_CONFIGURED"
     DEGRADED = "DEGRADED"
@@ -122,7 +126,7 @@ async def wrapper_service_query(*args, **kwargs):
             # TimeoutError is not caught
             executor = futures.ThreadPoolExecutor()
             try:
-                async with asyncio.timeout(DELAY):
+                async with asyncio.timeout(SERVICE_QUERY_TIMEOUT_S):
                     future = loop.run_in_executor(
                         executor, functools.partial(func, *args, **kwargs)
                     )
@@ -134,18 +138,20 @@ async def wrapper_service_query(*args, **kwargs):
 
             except TimeoutError:
                 # Timeout is an "expected" condition for a service that's expected
-                # to be running but may be degraded so we don't log it unless debugging.
-                logger.debug("Service query '%s' timed out", func.__name__)
-                state = State.TIMEOUT
+                # to be running but is taking too long to report its state
+                # and is also considered DEGRADED.
+                state = State.DEGRADED
             except Exception as exc:
                 # unknown error with the query
                 logger.exception(exc, exc_info=True)
                 state = State.ERROR
 
-        # name and ID are 1nd and 0th params respectively.
-        # alternative solution for this would be to return just a
+        # ID and Name are the 1st and 2nd params respectively.
+        # Alternative solution for this would be to return just a
         # state and have the service_queries() map the results to the
         # correct values
+        if state not in [State.OK, State.NOT_CONFIGURED]:
+            logger.info('"%s" is %s', args[1], state.name)
         return {"id": args[0], "name": args[1], "state": state}
 
     return wrapper_service_query