Remove support for the legacy structured logging configuration. (#12008)

Author: clokep

changelog.d/12008.removal

@@ -0,0 +1 @@
+Remove support for the legacy structured logging configuration (please see the the [upgrade notes](https://matrix-org.github.io/synapse/develop/upgrade#legacy-structured-logging-configuration-removal) if you are using `structured: true` in the Synapse configuration).

docs/structured_logging.md

@@ -81,14 +81,12 @@ remote endpoint at 10.1.2.3:9999.
 
 ## Upgrading from legacy structured logging configuration
 
-Versions of Synapse prior to v1.23.0 included a custom structured logging
-configuration which is deprecated. It used a `structured: true` flag and
-configured `drains` instead of ``handlers`` and `formatters`.
-
-Synapse currently automatically converts the old configuration to the new
-configuration, but this will be removed in a future version of Synapse. The
-following reference can be used to update your configuration. Based on the drain
-`type`, we can pick a new handler:
+Versions of Synapse prior to v1.54.0 automatically converted the legacy
+structured logging configuration, which was deprecated in v1.23.0, to the standard
+library logging configuration.
+
+The following reference can be used to update your configuration. Based on the
+drain `type`, we can pick a new handler:
 
 1. For a type of `console`, `console_json`, or `console_json_terse`: a handler
    with a class of `logging.StreamHandler` and a `stream` of `ext://sys.stdout`

docs/upgrade.md

@@ -85,6 +85,15 @@ process, for example:
     dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
     ```
 
+# Upgrading to v1.54.0
+
+## Legacy structured logging configuration removal
+
+This release removes support for the `structured: true` logging configuration
+which was deprecated in Synapse v1.23.0. If your logging configuration contains
+`structured: true` then it should be modified based on the
+[structured logging documentation](structured_logging.md).
+
 # Upgrading to v1.53.0
 
 ## Dropping support for `webclient` listeners and non-HTTP(S) `web_client_location`

synapse/config/logger.py

@@ -33,7 +33,6 @@
     globalLogBeginner,
 )
 
-from synapse.logging._structured import setup_structured_logging
 from synapse.logging.context import LoggingContextFilter
 from synapse.logging.filter import MetadataFilter
 
@@ -138,6 +137,12 @@
 removed in Synapse 1.3.0. You should instead set up a separate log configuration file.
 """
 
+STRUCTURED_ERROR = """\
+Support for the structured configuration option was removed in Synapse 1.54.0.
+You should instead use the standard logging configuration. See
+https://matrix-org.github.io/synapse/v1.54/structured_logging.html
+"""
+
 
 class LoggingConfig(Config):
     section = "logging"
@@ -292,10 +297,9 @@ def _load_logging_config(log_config_path: str) -> None:
     if not log_config:
         logging.warning("Loaded a blank logging config?")
 
-    # If the old structured logging configuration is being used, convert it to
-    # the new style configuration.
+    # If the old structured logging configuration is being used, raise an error.
     if "structured" in log_config and log_config.get("structured"):
-        log_config = setup_structured_logging(log_config)
+        raise ConfigError(STRUCTURED_ERROR)
 
     logging.config.dictConfig(log_config)