Workaround a Linux TZ issue (#40)

Author: randallfrank

src/ansys/dynamicreporting/core/utils/report_remote_server.py

@@ -1005,6 +1005,9 @@ def create_new_local_database(
 
         return False
 
+    # Check for Linux TZ issue
+    report_utils.apply_timezone_workaround()
+
     try:
         if run_local:
             # Make a random string that could be used as a secret key for the database
@@ -1348,6 +1351,9 @@ def launch_local_database_server(
     if return_info is None:
         return_info = dict()
 
+    # Check for Linux TZ issue
+    report_utils.apply_timezone_workaround()
+
     # Try to use a lock file to prevent port scanning collisions
     # We create a lockfiles in the user's home directory.  Under windows, we use LOCALAPPDATA to avoid
     # the case where a home dir may be mounted remotely, potentially causing permission issues when writing.

src/ansys/dynamicreporting/core/utils/report_utils.py

@@ -739,3 +739,35 @@ def get_links_from_html(html):
     parser = HTMLParser()
     parser.feed(html)
     return parser.links
+
+
+def apply_timezone_workaround() -> None:
+    """
+    Apply a workaround for known Linux system misconfigurations.
+
+    There is a known issue on some Linux systems where the timezone configuration is
+    incorrect. On these systems, the get_localzone_name() call will raise an exception
+    that prevents a Django instance from starting.  This effects the Nexus server as
+    well as the adr API for doing things like creating a database.
+
+    The work-around is to try to trigger the exception early and (on failure) set the TZ
+    environmental variable  to a known value and warn the user that this has been done.
+    If the user sets TZ or corrects the system misconfiguration, that will also fix the
+    issue.
+    """
+    try:
+        # Attempt to trigger the misconfiguration issue.
+        import tzlocal
+
+        _ = tzlocal.get_localzone_name()
+    except ModuleNotFoundError:
+        # tzlocal is only used by the Django code, so if it is not present,
+        return
+    except KeyError as e:
+        # Issue a warning
+        import warnings
+
+        msg = "The timezone of this session is not configured correctly, trying 'US/Eastern' : "
+        warnings.warn(msg + str(e))
+        # Try a relatively well known TZ
+        os.environ["TZ"] = "US/Eastern"