logs: use less heavy structure for journald logging

features/unattached_commands.feature

@@ -346,7 +346,7 @@ Feature: Command behaviour when unattached
         """
         Then stdout matches regexp:
         """
-        "WARNING", "ubuntupro.apt", "fail", \d+, "Failed to fetch ESM Apt Cache item: https://esm.ubuntu.com/apps/ubuntu/dists/<release>-apps-security/InRelease", {}]
+        WARNING|ubuntupro.apt|fail|\d+|Failed to fetch ESM Apt Cache item: https://esm.ubuntu.com/apps/ubuntu/dists/<release>-apps-security/InRelease|{}
         """
         When I run `ls /var/crash/` with sudo
         Then stdout does not contain substring:

uaclient/log.py

@@ -1,9 +1,10 @@
+import abc
 import json
 import logging
 import os
 import pathlib
 from collections import OrderedDict
-from typing import Any, Dict, List, Union  # noqa: F401
+from typing import Any, Dict, List, Tuple, Union  # noqa: F401
 
 from uaclient import defaults, system, util
 from uaclient.config import UAConfig
@@ -17,9 +18,10 @@ def filter(self, record: logging.LogRecord):
         return True
 
 
-class JsonArrayFormatter(logging.Formatter):
-    """Json Array Formatter for our logging mechanism
-    Custom made for Pro logging needs
+class BaseProFormatter(logging.Formatter, metaclass=abc.ABCMeta):
+    """Formatter class that collects all the fields we care about in the
+    correct order and calls a subclass defined formatter function to turn
+    it into a string.
     """
 
     default_time_format = "%Y-%m-%dT%H:%M:%S"
@@ -31,7 +33,7 @@ class JsonArrayFormatter(logging.Formatter):
         "funcName",
         "lineno",
         "message",
-    )
+    )  # type: Tuple[str, ...]
 
     def format(self, record: logging.LogRecord) -> str:
         record.message = record.getMessage()
@@ -60,7 +62,42 @@ def format(self, record: logging.LogRecord) -> str:
             local_log_record[field] = value
 
         local_log_record["extra"] = extra_message_dict
-        return json.dumps(list(local_log_record.values()))
+        return self.subformatter(local_log_record)
+
+    @abc.abstractmethod
+    def subformatter(self, d: Dict[str, Any]) -> str:
+        pass
+
+
+class JsonArrayFormatter(BaseProFormatter):
+    def subformatter(self, d: Dict[str, Any]) -> str:
+        return json.dumps(list(d.values()))
+
+
+class JournaldFormatter(BaseProFormatter):
+    """Logging to journald in json format is considered unideal
+    This formatter includes all the same fields, separated by `|`
+    characters to maintain structure
+    """
+
+    required_fields = (
+        # no need for asctime because journald already has the time
+        "levelname",
+        "name",
+        "funcName",
+        "lineno",
+        "message",
+    )
+
+    def subformatter(self, d: Dict[str, Any]) -> str:
+        values = []
+        for v in d.values():
+            if isinstance(v, str):
+                values.append(v)
+            else:
+                # json format only for non string types
+                values.append(json.dumps(v))
+        return "|".join(values)
 
 
 def get_user_or_root_log_file_path() -> str:
@@ -104,7 +141,7 @@ def setup_journald_logging():
     logger.setLevel(logging.INFO)
     logger.addFilter(RedactionFilter())
     console_handler = logging.StreamHandler()
-    console_handler.setFormatter(JsonArrayFormatter())
+    console_handler.setFormatter(JournaldFormatter())
     console_handler.setLevel(logging.INFO)
     logger.addHandler(console_handler)