Logging

The logging observer adds request-specific metadata to log lines coming out of your application.

Changed in version 1.4: Logs are now formatted as JSON objects.

Configuration

No configuration is necessary, this observer is always enabled when you call configure_observers().

If your application is run with baseplate-serve, logging can be controlled with Python’s standard logging configuration. See Logging for more information.

Outputs

The baseplate-serve command will automatically set up log formatting.

When directly used from a TTY, a simplified human-readable message format is emitted. Only the level and message are included.

In production usage, log entries are formatted as JSON objects that can be parsed automatically by log analysis systems. Log entry objects contain the following keys:

message

The message.

level

The name of the log level at which the log entry was generated, e.g. INFO, WARNING, etc.

Along with name, this can be useful for configuring logging to squelch noisy messages.

name

The name of the Logger used.

Along with level, this can be useful for configuring logging to squelch noisy messages.

traceID

The Trace ID of the request within context of which the log entry was generated. This can be used to correlate log entries from the same root request within and across services.

Only present if the log entry was generated during a request. Otherwise see thread.

pathname

The path to the Python source for the module that generated the log entry.

module

The name of the module in which the log entry was generated.

funcName

The name of the function that generated the log entry.

lineno

The line number on which the log entry was generated.

process

The OS-level Process ID of the process that generated the log entry.

processName

The name of the process that generated the log entry (as set on multiprocessing.current_process().name).

thread

The name of the thread that generated the log entry (as set on threading.current_thread().name).

This may be absent if the log entry was generated from within processing of a request, in which case traceID will be included instead.

Older logging

Before v1.4, log entries were written in a custom format:

17905:7296338476964580186:baseplate.lib.metrics:DEBUG:Blah blah
^     ^                   ^                     ^     ^
|     |                   |                     |     Log message
|     |                   |                     Log level
|     |                   Name of the logger
|     Trace ID of the request
Process ID

Direct Use

Any log messages emitted with the Python standard logging interfaces will be annotated by this observer.