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1# Copyright 2021 The Pigweed Authors
2#
3# Licensed under the Apache License, Version 2.0 (the "License"); you may not
4# use this file except in compliance with the License. You may obtain a copy of
5# the License at
6#
7#     https://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12# License for the specific language governing permissions and limitations under
13# the License.
14"""Python logging helper fuctions."""
15
16import copy
17from datetime import datetime
18import json
19import logging
20import tempfile
21from typing import Any, Dict, Iterable, Iterator, Optional
22
23
24def all_loggers() -> Iterator[logging.Logger]:
25    """Iterates over all loggers known to Python logging."""
26    manager = logging.getLogger().manager  # type: ignore[attr-defined]
27
28    for logger_name in manager.loggerDict:  # pylint: disable=no-member
29        yield logging.getLogger(logger_name)
30
31
32def create_temp_log_file(
33    prefix: Optional[str] = None, add_time: bool = True
34) -> str:
35    """Create a unique tempfile for saving logs.
36
37    Example format: /tmp/pw_console_2021-05-04_151807_8hem6iyq
38    """
39    if not prefix:
40        prefix = str(__package__)
41
42    # Grab the current system timestamp as a string.
43    isotime = datetime.now().isoformat(sep="_", timespec="seconds")
44    # Timestamp string should not have colons in it.
45    isotime = isotime.replace(":", "")
46
47    if add_time:
48        prefix += f"_{isotime}"
49
50    log_file_name = None
51    with tempfile.NamedTemporaryFile(
52        prefix=f"{prefix}_", delete=False
53    ) as log_file:
54        log_file_name = log_file.name
55
56    return log_file_name
57
58
59def set_logging_last_resort_file_handler(
60    file_name: Optional[str] = None,
61) -> None:
62    log_file = file_name if file_name else create_temp_log_file()
63    logging.lastResort = logging.FileHandler(log_file)
64
65
66def disable_stdout_handlers(logger: logging.Logger) -> None:
67    """Remove all stdout and stdout & stderr logger handlers."""
68    for handler in copy.copy(logger.handlers):
69        # Must use type() check here since this returns True:
70        #   isinstance(logging.FileHandler, logging.StreamHandler)
71        # pylint: disable=unidiomatic-typecheck
72        if type(handler) == logging.StreamHandler:
73            logger.removeHandler(handler)
74        # pylint: enable=unidiomatic-typecheck
75
76
77def setup_python_logging(
78    last_resort_filename: Optional[str] = None,
79    loggers_with_no_propagation: Optional[Iterable[logging.Logger]] = None,
80) -> None:
81    """Disable log handlers for full screen prompt_toolkit applications."""
82    if not loggers_with_no_propagation:
83        loggers_with_no_propagation = []
84    disable_stdout_handlers(logging.getLogger())
85
86    if logging.lastResort is not None:
87        set_logging_last_resort_file_handler(last_resort_filename)
88
89    for logger in list(all_loggers()):
90        # Prevent stdout handlers from corrupting the prompt_toolkit UI.
91        disable_stdout_handlers(logger)
92        if logger in loggers_with_no_propagation:
93            continue
94        # Make sure all known loggers propagate to the root logger.
95        logger.propagate = True
96
97    # Prevent these loggers from propagating to the root logger.
98    hidden_host_loggers = [
99        "pw_console",
100        "pw_console.plugins",
101        # prompt_toolkit triggered debug log messages
102        "prompt_toolkit",
103        "prompt_toolkit.buffer",
104        "parso.python.diff",
105        "parso.cache",
106        "pw_console.serial_debug_logger",
107    ]
108    for logger_name in hidden_host_loggers:
109        logging.getLogger(logger_name).propagate = False
110
111    # Set asyncio log level to WARNING
112    logging.getLogger("asyncio").setLevel(logging.WARNING)
113
114    # Always set DEBUG level for serial debug.
115    logging.getLogger("pw_console.serial_debug_logger").setLevel(logging.DEBUG)
116
117
118def log_record_to_json(record: logging.LogRecord) -> str:
119    log_dict: Dict[str, Any] = {}
120    log_dict["message"] = record.getMessage()
121    log_dict["levelno"] = record.levelno
122    log_dict["levelname"] = record.levelname
123    log_dict["args"] = record.args
124
125    if hasattr(record, "extra_metadata_fields") and (
126        record.extra_metadata_fields  # type: ignore
127    ):
128        fields = record.extra_metadata_fields  # type: ignore
129        log_dict["fields"] = {}
130        for key, value in fields.items():
131            if key == "msg":
132                log_dict["message"] = value
133                continue
134
135            log_dict["fields"][key] = str(value)
136
137    return json.dumps(log_dict)
138
139
140class JsonLogFormatter(logging.Formatter):
141    """Json Python logging Formatter
142
143    Use this formatter to log pw_console messages to a file in json
144    format. Column values normally shown in table view will be populated in the
145    'fields' key.
146
147    Example log entry:
148
149    .. code-block:: json
150
151       {
152         "message": "System init",
153         "levelno": 20,
154         "levelname": "INF",
155         "args": [
156           "0:00",
157           "pw_system ",
158           "System init"
159         ],
160         "fields": {
161           "module": "pw_system",
162           "file": "pw_system/init.cc",
163           "timestamp": "0:00"
164         }
165       }
166
167    Example usage:
168
169    .. code-block:: python
170
171       import logging
172       import pw_console.python_logging
173
174       _DEVICE_LOG = logging.getLogger('rpc_device')
175
176       json_filehandler = logging.FileHandler('logs.json', encoding='utf-8')
177       json_filehandler.setLevel(logging.DEBUG)
178       json_filehandler.setFormatter(
179           pw_console.python_logging.JsonLogFormatter())
180       _DEVICE_LOG.addHandler(json_filehandler)
181
182    """
183
184    def __init__(self, *args, **kwargs):
185        super().__init__(*args, **kwargs)
186
187    def format(self, record: logging.LogRecord) -> str:
188        return log_record_to_json(record)
189