# dokumentasi Django 2.2.9.dev20191202104323

# Pencatatan

## A quick logging primer

Django uses Python's builtin `logging` module to perform system logging. The usage of this module is discussed in detail in Python's own documentation. However, if you've never used Python's logging framework (or even if you have), here's a quick primer.

### The cast of players

A Python logging configuration consists of four parts:

- Pencatat
- Penangan
- Filter
- Pembentuk

#### Pencatat

A logger is the entry point into the logging system. Each logger is a named bucket to which messages can be written for processing.

A logger is configured to have a log level. This log level describes the severity of the messages that the logger will handle. Python defines the following log levels:

- `DEBUG`: Sistm informasi tingkat rendah untuk tujuan mencari kesalahan
- `INFO`: Informasi Sistem Umum
- `PERINGATAN`: Informasi menggambarkan masalah kecil yang telah muncul.
- `KESALAHAN`: Informasi menggambarkan masalah yang telah muncul.
- `KRITIS`: Informasi menggambarkan masalah kritis yang muncul.

Each message that is written to the logger is a Log Record. Each log record also has a log level indicating the severity of that specific message. A log record can also contain useful metadata that describes the event that is being logged. This can include details such as a stack trace or an error code.

When a message is given to the logger, the log level of the message is compared to the log level of the logger. If the log level of the message meets or exceeds the log level of the logger itself, the message will undergo further processing. If it doesn't, the message will be ignored.

Once a logger has determined that a message needs to be processed, it is passed to a Handler.

#### Penangan

The handler is the engine that determines what happens to each message in a logger. It describes a particular logging behavior, such as writing a message to the screen, to a file, or to a network socket.

Like loggers, handlers also have a log level. If the log level of a log record doesn't meet or exceed the level of the handler, the handler will ignore the message.

A logger can have multiple handlers, and each handler can have a different log level. In this way, it is possible to provide different forms of notification depending on the importance of a message. For example, you could install one handler that forwards `ERROR` and `CRITICAL` messages to a paging service, while a second handler logs all messages (including `ERROR` and `CRITICAL` messages) to a file for later analysis.

#### Filter

Sebuah penyaring digunakan untuk menyediakan tambahan pengendali terhadap rekaman catatan dilewatkan dari pencatat ke penangan.

By default, any log message that meets log level requirements will be handled. However, by installing a filter, you can place additional criteria on the logging process. For example, you could install a filter that only allows `ERROR` messages from a particular source to be emitted.

Filters can also be used to modify the logging record prior to being emitted. For example, you could write a filter that downgrades `ERROR` log records to `WARNING` records if a particular set of criteria are met.

Filters can be installed on loggers or on handlers; multiple filters can be used in a chain to perform multiple filtering actions.

#### Pembentuk

Ultimately, a log record needs to be rendered as text. Formatters describe the exact format of that text. A formatter usually consists of a Python formatting string containing LogRecord attributes; however, you can also write custom formatters to implement specific formatting behavior.

## Menggunakan pencatatan

Once you have configured your loggers, handlers, filters and formatters, you need to place logging calls into your code. Using the logging framework is very simple. Here's an example:

    # import the logging library
    import logging

    # Get an instance of a logger
    logger = logging.getLogger(__name__)

    def my_view(request, arg1, arg):
        ...
        if bad_mojo:
            # Log an error message
            logger.error('Something went wrong!')

And that's it! Every time the `bad_mojo` condition is activated, an error log record will be written.

### Menamai pencatat

The call to `logging.getLogger()` obtains (creating, if necessary) an instance of a logger. The logger instance is identified by a name. This name is used to identify the logger for configuration purposes.

By convention, the logger name is usually `__name__`, the name of the Python module that contains the logger. This allows you to filter and handle logging calls on a per-module basis. However, if you have some other way of organizing your logging messages, you can provide any dot-separated name to identify your logger:

    # Get an instance of a specific named logger
    logger = logging.getLogger('project.interesting.stuff')

The dotted paths of logger names define a hierarchy. The `project.interesting` logger is considered to be a parent of the `project.interesting.stuff` logger; the `project` logger is a parent of the `project.interesting` logger.

Why is the hierarchy important? Well, because loggers can be set to propagate their logging calls to their parents. In this way, you can define a single set of handlers at the root of a logger tree, and capture all logging calls in the subtree of loggers. A logging handler defined in the `project` namespace will catch all logging messages issued on the `project.interesting` and `project.interesting.stuff` loggers.

This propagation can be controlled on a per-logger basis. If you don't want a particular logger to propagate to its parents, you can turn off this behavior.

### Membuat pencatatan panggilan

Contoh pencatat mengandung sebuah masukan metode untuk setiap tingkat catatan awalan:

- `logger.debug()`
- `logger.info()`
- `logger.warning()`
- `logger.error()`
- `logger.critical()`

Ada dua catatan panggilan lain tersedia:

- `logger.log()`: Manually emits a logging message with a specific log level.
- `logger.exception()`: Creates an `ERROR` level logging message wrapping the current exception stack frame.

## Mengkonfigurasi catatan

Of course, it isn't enough to just put logging calls into your code. You also need to configure the loggers, handlers, filters and formatters to ensure that logging output is output in a useful way.

Python's logging library provides several techniques to configure logging, ranging from a programmatic interface to configuration files. By default, Django uses the dictConfig format.

In order to configure logging, you use `LOGGING` to define a dictionary of logging settings. These settings describes the loggers, handlers, filters and formatters that you want in your logging setup, and the log levels and other properties that you want those components to have.

By default, the `LOGGING` setting is merged with Django's default logging configuration using the following scheme.

If the `disable_existing_loggers` key in the `LOGGING` dictConfig is set to `True` (which is the `dictConfig` default if the key is missing) then all loggers from the default configuration will be disabled. Disabled loggers are not the same as removed; the logger will still exist, but will silently discard anything logged to it, not even propagating entries to a parent logger. Thus you should be very careful using `'disable_existing_loggers': True`; it's probably not what you want. Instead, you can set `disable_existing_loggers` to `False` and redefine some or all of the default loggers; or you can set `LOGGING_CONFIG` to `None` and handle logging config yourself.

Logging is configured as part of the general Django `setup()` function. Therefore, you can be certain that loggers are always ready for use in your project code.

### Contoh

The full documentation for dictConfig format is the best source of information about logging configuration dictionaries. However, to give you a taste of what is possible, here are several examples.

First, here's a simple configuration which writes all logging from the django logger to a local file:

    LOGGING = {
        'version': 1,
        'disable_existing_loggers': False,
        'handlers': {
            'file': {
                'level': 'DEBUG',
                'class': 'logging.FileHandler',
                'filename': '/path/to/django/debug.log',
            },
        },
        'loggers': {
            'django': {
                'handlers': ['file'],
                'level': 'DEBUG',
                'propagate': True,
            },
        },
    }

If you use this example, be sure to change the `'filename'` path to a location that's writable by the user that's running the Django application.

Kedua, ini adalah sebuah contoh dari bagaimana membuat sistem pencatatan mencetak penactatan Django ke konsol. Itu mungkin berguna selama pengembangan lokal.

By default, this config only sends messages of level `INFO` or higher to the console (same as Django's default logging config, except that the default only displays log records when `DEBUG=True`). Django does not log many such messages. With this config, however, you can also set the environment variable `DJANGO_LOG_LEVEL=DEBUG` to see all of Django's debug logging which is very verbose as it includes all database queries:

    import os

    LOGGING = {
        'version': 1,
        'disable_existing_loggers': False,
        'handlers': {
            'console': {
                'class': 'logging.StreamHandler',
            },
        },
        'loggers': {
            'django': {
                'handlers': ['console'],
                'level': os.getenv('DJANGO_LOG_LEVEL', 'INFO'),
            },
        },
    }

Akhirnya, ini adalah sebuah contoh dari penyetelan pencatatan cukup rumit:

    LOGGING = {
        'version': 1,
        'disable_existing_loggers': False,
        'formatters': {
            'verbose': {
                'format': '{levelname} {asctime} {module} {process:d} {thread:d} {message}',
                'style': '{',
            },
            'simple': {
                'format': '{levelname} {message}',
                'style': '{',
            },
        },
        'filters': {
            'special': {
                '()': 'project.logging.SpecialFilter',
                'foo': 'bar',
            },
            'require_debug_true': {
                '()': 'django.utils.log.RequireDebugTrue',
            },
        },
        'handlers': {
            'console': {
                'level': 'INFO',
                'filters': ['require_debug_true'],
                'class': 'logging.StreamHandler',
                'formatter': 'simple'
            },
            'mail_admins': {
                'level': 'ERROR',
                'class': 'django.utils.log.AdminEmailHandler',
                'filters': ['special']
            }
        },
        'loggers': {
            'django': {
                'handlers': ['console'],
                'propagate': True,
            },
            'django.request': {
                'handlers': ['mail_admins'],
                'level': 'ERROR',
                'propagate': False,
            },
            'myproject.custom': {
                'handlers': ['console', 'mail_admins'],
                'level': 'INFO',
                'filters': ['special']
            }
        }
    }

Konfigurasi pencatatan ini melakukan hal-hal berikut:

- Identifies the configuration as being in 'dictConfig version 1' format. At present, this is the only dictConfig format version.

- Menentukan dua pembentuk:

  - `simple`, itu hanya mengeluarkan catatan nama tingkat (sebagai contoh `DEBUG`) dan catatan pesan.

    The `format` string is a normal Python formatting string describing the details that are to be output on each logging line. The full list of detail that can be output can be found in Formatter Objects.

  - `verbose`, that outputs the log level name, the log message, plus the time, process, thread and module that generate the log message.

- Menentukan dua penyaring:

  - `project.logging.SpecialFilter`, using the alias `special`. If this filter required additional arguments, they can be provided as additional keys in the filter configuration dictionary. In this case, the argument `foo` will be given a value of `bar` when instantiating `SpecialFilter`.
  - `django.utils.log.RequireDebugTrue`, yang melewatkan pada rekaman-rekaman ketika `DEBUG` adalah `True`.

- Menentukan dua penangan:

  - `console`, sebuah `StreamHandler`, yang mencetak pesan `INFO` apapun (atau lebih tinggi) ke `sys.stderr`. Penangan ini menggunakan bentuk keluaran `simple`.
  - `mail_admins`, sebuah `AdminEmailHandler`, yang mensurelkan pesan `ERROR` apapun (atau lebih tinggi) ke situs `ADMINS`. Penangan ini menggunakan penyaring `special`.

- Mengkonfigurasi tiga pencatat:

  - `django`, yang melewatkan semua pesan-pesan ke penangan `console`.
  - `django.request`, which passes all `ERROR` messages to the `mail_admins` handler. In addition, this logger is marked to not propagate messages. This means that log messages written to `django.request` will not be handled by the `django` logger.
  - `myproject.custom`, which passes all messages at `INFO` or higher that also pass the `special` filter to two handlers -- the `console`, and `mail_admins`. This means that all `INFO` level messages (or higher) will be printed to the console; `ERROR` and `CRITICAL` messages will also be output via email.

### Konfigurasi pencatatan penyesuaian

Jika anda tidak ingin menggunakan bentuk dictConfig Python untuk mengkonfigurasi pencatat anda, anda dapat menentukan skema konfigurasi anda sendiri.

The `LOGGING_CONFIG` setting defines the callable that will be used to configure Django's loggers. By default, it points at Python's `logging.config.dictConfig()` function. However, if you want to use a different configuration process, you can use any other callable that takes a single argument. The contents of `LOGGING` will be provided as the value of that argument when logging is configured.

### Meniadakan konfigurasi pencatatan

If you don't want to configure logging at all (or you want to manually configure logging using your own approach), you can set `LOGGING_CONFIG` to `None`. This will disable the configuration process for Django's default logging. Here's an example that disables Django's logging configuration and then manually configures logging:

settings.py

    LOGGING_CONFIG = None

    import logging.config
    logging.config.dictConfig(...)

Setting `LOGGING_CONFIG` to `None` only means that the automatic configuration process is disabled, not logging itself. If you disable the configuration process, Django will still make logging calls, falling back to whatever default logging behavior is defined.

## Tambahan pencatatan Django

Django menyediakan sejumlah perlengkapan untuk menangani persyaratan unik dari pencatatan dalam lingkungan peladen Jaringan.

### Pencatat

Django menyediakan beberapa pencatat siap-pakai.

#### `django`

The catch-all logger for messages in the `django` hierarchy. No messages are posted using this name but instead using one of the loggers below.

#### `django.request`

Log messages related to the handling of requests. 5XX responses are raised as `ERROR` messages; 4XX responses are raised as `WARNING` messages. Requests that are logged to the `django.security` logger aren't logged to `django.request`.

Pesan-pesan ke pencatat ini mempunyai konteks tambahan berikut:

- `status_code`: Kode tanggapan HTTP terkait dengan permintaan.
- `request`: Obyek permintaan yang membangkitkan pesan pencatatan.

#### `django.server`

Log messages related to the handling of requests received by the server invoked by the `runserver` command. HTTP 5XX responses are logged as `ERROR` messages, 4XX responses are logged as `WARNING` messages, and everything else is logged as `INFO`.

Pesan-pesan ke pencatat ini mempunyai konteks tambahan berikut:

- `status_code`: Kode tanggapan HTTP terkait dengan permintaan.
- `request`: Obyek permintaan yang membangkitkan pesan pencatatan.

#### `django.template`

Pesan-pesan catatan terkait pada membangun cetakan.

- Missing context variables are logged as `DEBUG` messages.

#### `django.db.backends`

Messages relating to the interaction of code with the database. For example, every application-level SQL statement executed by a request is logged at the `DEBUG` level to this logger.

Pesan-pesan ke pencatat ini mempunyai konteks tambahan berikut:

- `duration`: Waktu diambil untuk menjalankan pernyataan SQL.
- `sql`: Pernyataan SQL yang telah dijalankan.
- `params`: Parameter yang telah digunakan dalam panggilan SQL.

For performance reasons, SQL logging is only enabled when `settings.DEBUG` is set to `True`, regardless of the logging level or handlers that are installed.

This logging does not include framework-level initialization (e.g. `SET TIMEZONE`) or transaction management queries (e.g. `BEGIN`, `COMMIT`, and `ROLLBACK`). Turn on query logging in your database if you wish to view all database queries.

#### `django.security.*`

The security loggers will receive messages on any occurrence of `SuspiciousOperation` and other security-related errors. There is a sub-logger for each subtype of security error, including all `SuspiciousOperation`s. The level of the log event depends on where the exception is handled. Most occurrences are logged as a warning, while any `SuspiciousOperation` that reaches the WSGI handler will be logged as an error. For example, when an HTTP `Host` header is included in a request from a client that does not match `ALLOWED_HOSTS`, Django will return a 400 response, and an error message will be logged to the `django.security.DisallowedHost` logger.

These log events will reach the `django` logger by default, which mails error events to admins when `DEBUG=False`. Requests resulting in a 400 response due to a `SuspiciousOperation` will not be logged to the `django.request` logger, but only to the `django.security` logger.

To silence a particular type of `SuspiciousOperation`, you can override that specific logger following this example:

    'handlers': {
        'null': {
            'class': 'logging.NullHandler',
        },
    },
    'loggers': {
        'django.security.DisallowedHost': {
            'handlers': ['null'],
            'propagate': False,
        },
    },

Pencatat `django.security` lain bukan berdasarkan pada `SuspiciousOperation` adalah:

- `django.security.csrf`: Untuk CSRF failures 1.

#### `django.db.backends.schema`

Logs the SQL queries that are executed during schema changes to the database by the migrations framework. Note that it won't log the queries executed by `RunPython`. Messages to this logger have `params` and `sql` in their extra context (but unlike `django.db.backends`, not duration). The values have the same meaning as explained in django.db.backends.

### Penangan

Django menyediakan satu penangan catatan sebagai tambahan yang disediakan oleh modul pencatatan Python.

class `AdminEmailHandler`(include_html=False, email_backend=None)

  This handler sends an email to the site `ADMINS` for each log message it receives.

  If the log record contains a `request` attribute, the full details of the request will be included in the email. The email subject will include the phrase "internal IP" if the client's IP address is in the `INTERNAL_IPS` setting; if not, it will include "EXTERNAL IP".

  If the log record contains stack trace information, that stack trace will be included in the email.

  The `include_html` argument of `AdminEmailHandler` is used to control whether the traceback email includes an HTML attachment containing the full content of the debug Web page that would have been produced if `DEBUG` were `True`. To set this value in your configuration, include it in the handler definition for `django.utils.log.AdminEmailHandler`, like this:

      'handlers': {
          'mail_admins': {
              'level': 'ERROR',
              'class': 'django.utils.log.AdminEmailHandler',
              'include_html': True,
          }
      },

  Note that this HTML version of the email contains a full traceback, with names and values of local variables at each level of the stack, plus the values of your Django settings. This information is potentially very sensitive, and you may not want to send it over email. Consider using something such as Sentry to get the best of both worlds -- the rich information of full tracebacks plus the security of not sending the information over email. You may also explicitly designate certain sensitive information to be filtered out of error reports -- learn more on Filtering error reports.

  By setting the `email_backend` argument of `AdminEmailHandler`, the email backend that is being used by the handler can be overridden, like this:

      'handlers': {
          'mail_admins': {
              'level': 'ERROR',
              'class': 'django.utils.log.AdminEmailHandler',
              'email_backend': 'django.core.mail.backends.filebased.EmailBackend',
          }
      },

  Secara awalan, sebuah instance dari backend surel ditentukan dalam `EMAIL_BACKEND` akan digunakan.

  `send_mail`(subject, message, *args, **kwargs)

    Sends emails to admin users. To customize this behavior, you can subclass the `AdminEmailHandler` class and override this method.

### Filter

Django provides some log filters in addition to those provided by the Python logging module.

class `CallbackFilter`(callback)

  This filter accepts a callback function (which should accept a single argument, the record to be logged), and calls it for each record that passes through the filter. Handling of that record will not proceed if the callback returns False.

  For instance, to filter out `UnreadablePostError` (raised when a user cancels an upload) from the admin emails, you would create a filter function:

      from django.http import UnreadablePostError

      def skip_unreadable_post(record):
          if record.exc_info:
              exc_type, exc_value = record.exc_info[:2]
              if isinstance(exc_value, UnreadablePostError):
                  return False
          return True

  dan kemudian tambah itu ke konfigurasi pencatatan anda:

      'filters': {
          'skip_unreadable_posts': {
              '()': 'django.utils.log.CallbackFilter',
              'callback': skip_unreadable_post,
          }
      },
      'handlers': {
          'mail_admins': {
              'level': 'ERROR',
              'filters': ['skip_unreadable_posts'],
              'class': 'django.utils.log.AdminEmailHandler'
          }
      },

class `RequireDebugFalse`

  Penyaring ini hanya akan dilewatkan pada rekaman ketika settings.DEBUG adalah False.

  This filter is used as follows in the default `LOGGING` configuration to ensure that the `AdminEmailHandler` only sends error emails to admins when `DEBUG` is `False`:

      'filters': {
          'require_debug_false': {
              '()': 'django.utils.log.RequireDebugFalse',
          }
      },
      'handlers': {
          'mail_admins': {
              'level': 'ERROR',
              'filters': ['require_debug_false'],
              'class': 'django.utils.log.AdminEmailHandler'
          }
      },

class `RequireDebugTrue`

  This filter is similar to `RequireDebugFalse`, except that records are passed only when `DEBUG` is `True`.

## Konfigurasi pencatatan awalan Django

Secara awalan, Django mengkonfigurasi pencatatan berikut:

ketika `DEBUG` adalah `True`:

- The `django` logger sends messages in the `django` hierarchy (except `django.server`) at the `INFO` level or higher to the console.

Ketika `DEBUG` adalah `False`;

- The `django` logger sends messages in the `django` hierarchy (except `django.server`) with `ERROR` or `CRITICAL` level to `AdminEmailHandler`.

Independent of the value of `DEBUG`:

- The django.server logger sends messages at the `INFO` level or higher to the console.

All loggers except django.server propagate logging to their parents, up to the root `django` logger. The `console` and `mail_admins` handlers are attached to the root logger to provide the behavior described above.

See also Configuring logging to learn how you can complement or replace this default logging configuration defined in django/utils/log.py.