Log

This section configures event logging. It is optional and cannot be reloaded. If set, the root value must reside in the main configuration file.

Root Value

The root value may be a simple string containing the driver name, for example:

  • discard

    Drops logs. This is the default.

  • journal

    Sends logs directly to journald.

  • syslog

    Sends logs directly to syslog.

  • stdout

    Sends logs to standard output.

In that form, the chosen driver becomes the default log configuration for all loggers.

The root value may also be a map with the following keys:

  • default

    optional, type: log config

    Default log configuration for loggers with no explicit config.

    default: discard

  • syslog

    optional, type: syslog

    Shared syslog driver configuration.

    default: not set

  • fluentd

    optional, type: fluentd

    Shared fluentd driver configuration.

    default: not set

  • request

    optional, type: log config

    Log configuration for request loggers.

    default: not set

  • task

    optional, type: log config

    Log configuration for task loggers.

    default: not set

Log Config Value

Each detailed log configuration may be a simple driver name or a map with the following keys:

  • journal

    optional, type: map

    Use the journal log driver. The map should be empty because no extra keys are currently defined.

  • syslog

    optional, type: syslog

    Use the syslog log driver.

  • fluentd

    optional, type: fluentd

    Use the fluentd log driver.

  • async_channel_size

    optional, type: usize

    Internal async channel size.

    default: 4096

  • async_thread_number

    optional, type: usize

    Number of async threads.

    This has no effect on discard and journal log driver.

    default: 1

  • io_error_sampling_offset

    optional, type: usize, max: 16

    The logger may encounter I/O errors. This controls how often they are reported: once every 2^n occurrences.

    This has no effect on discard and journal log driver.

    default: 10

Note

The discard driver has no configuration options, so there is no corresponding map field for it.

Drivers