feat: add systemd journal logging configuration

README.rst

@@ -478,6 +478,15 @@ Keys to take special care are the ones needed to configure Kafka and advertised_
    * - ``use_protobuf_formatter``
      - ``false``
      - If protobuf formatter should be used on protobuf schemas in order to normalize schemas. The formatter is used on top and independent of regular normalization and schemas will be persisted in a formatted state.
+   * - ``log_handler``
+     - ``stdout``
+     - Select the log handler. Default is standard output. Alternative log handler is ``systemd``.
+   * - ``log_level``
+     - ``DEBUG``
+     - Logging level. Default level is debug.
+   * - ``log_format``
+     - ``%(name)-20s\t%(threadName)s\t%(levelname)-8s\t%(message)s``
+     - Log format
 
 
 Authentication and authorization of Karapace Schema Registry REST API

karapace.config.json

@@ -9,6 +9,7 @@
     "group_id": "schema-registry",
     "host": "127.0.0.1",
     "log_level": "DEBUG",
+    "log_handler": "stdout",
     "port": 8081,
     "server_tls_certfile": null,
     "server_tls_keyfile": null,

mypy.ini

@@ -85,3 +85,6 @@ ignore_missing_imports = True
 
 [mypy-networkx.*]
 ignore_missing_imports = True
+
+[mypy-systemd.*]
+ignore_missing_imports = True

pyproject.toml

@@ -70,6 +70,7 @@ Issues = "https://github.com/Aiven-Open/karapace/issues"
 
 [project.optional-dependencies]
 sentry-sdk = ["sentry-sdk>=1.6.0"]
+systemd-logging = ["systemd-python==235"]
 ujson = ["ujson"]
 dev = [
   # Developer QoL

src/karapace/config.py

@@ -48,6 +48,7 @@ class Config(TypedDict):
     registry_authfile: str | None
     rest_authorization: bool
     rest_base_uri: str | None
+    log_handler: str | None
     log_level: str
     log_format: str
     master_eligibility: bool
@@ -125,6 +126,7 @@ class ConfigDefaults(Config, total=False):
     "registry_authfile": None,
     "rest_authorization": False,
     "rest_base_uri": None,
+    "log_handler": "stdout",
     "log_level": "DEBUG",
     "log_format": "%(name)-20s\t%(threadName)s\t%(levelname)-8s\t%(message)s",
     "master_eligibility": True,

src/karapace/karapace_all.py

@@ -2,10 +2,12 @@
 Copyright (c) 2023 Aiven Ltd
 See LICENSE for details
 """
+from __future__ import annotations
+
 from aiohttp.web_log import AccessLogger
 from contextlib import closing
 from karapace import version as karapace_version
-from karapace.config import read_config
+from karapace.config import Config, read_config
 from karapace.instrumentation.prometheus import PrometheusInstrumentation
 from karapace.kafka_rest_apis import KafkaRest
 from karapace.rapu import RestApp
@@ -21,6 +23,37 @@ class KarapaceAll(KafkaRest, KarapaceSchemaRegistryController):
     pass
 
 
+def _configure_logging(*, config: Config) -> None:
+    log_level = config.get("log_level", "DEBUG")
+    log_format = config.get("log_format", "%(name)-20s\t%(threadName)s\t%(levelname)-8s\t%(message)s")
+
+    root_handler: logging.Handler | None = None
+    log_handler = config.get("log_handler", None)
+    if "systemd" == log_handler:
+        from systemd import journal
+
+        root_handler = journal.JournalHandler(SYSLOG_IDENTIFIER="karapace")
+    if "stdout" == log_handler or log_handler is None:
+        root_handler = logging.StreamHandler(stream=sys.stdout)
+    else:
+        logging.basicConfig(level=logging.INFO, format=log_format)
+        logging.getLogger().setLevel(log_level)
+
+    if root_handler is not None:
+        root_handler.setFormatter(logging.Formatter(log_format))
+        root_handler.setLevel(log_level)
+        root_handler.set_name(name="karapace")
+        logging.root.addHandler(root_handler)
+
+    logging.root.setLevel(log_level)
+
+    if config.get("access_logs_debug") is True:
+        config["access_log_class"] = DebugAccessLogger
+        logging.getLogger("aiohttp.access").setLevel(logging.DEBUG)
+    else:
+        config["access_log_class"] = AccessLogger
+
+
 def main() -> int:
     parser = argparse.ArgumentParser(prog="karapace", description="Karapace: Your Kafka essentials in one tool")
     parser.add_argument("--version", action="version", help="show program version", version=karapace_version.__version__)
@@ -30,13 +63,7 @@ def main() -> int:
     with closing(arg.config_file):
         config = read_config(arg.config_file)
 
-    logging.basicConfig(level=logging.INFO, format=config["log_format"])
-    logging.getLogger().setLevel(config["log_level"])
-    if config.get("access_logs_debug") is True:
-        config["access_log_class"] = DebugAccessLogger
-        logging.getLogger("aiohttp.access").setLevel(logging.DEBUG)
-    else:
-        config["access_log_class"] = AccessLogger
+    _configure_logging(config=config)
 
     app: RestApp
     if config["karapace_rest"] and config["karapace_registry"]: